Download Key Elements of Green Design

Building
Greenwith
Wood
MODULE 1
Key Elements
of Green Design
What is Green Design?
“Green building is the practice of increasing the
efficiency with which buildings use resources - energy,
water, and materials - while reducing building impacts
on human health and the environment during the
building’s lifecycle, through better siting, design,
construction, operation, maintenance, and removal.” 1
The ultimate goal of a green design is to achieve
sustainability and open up new opportunities to
design and build structures that use less energy,
water and materials, and minimize impacts on human
health and the environment.
Green design embodies a holistic, integrated and
multidisciplinary approach in which every decision
is evaluated against multiple criteria to find the best
solution. As the understanding of green design has
increased in sophistication over the last two decades,
the strategies adopted have evolved, and the
quantitative performance of buildings has improved.
1 Frej, Anne B., editor. Green Office Buildings: A Practical Guide to Development.
Washington, D.C.: ULI--The Urban Land Institute, 2005. Pp 4-8.
Green design incorporates environmental
considerations into every stage of a building’s life –
from the earliest planning through site development,
design, construction, operation and maintenance and,
eventually, decommissioning, reuse or disposal.
It involves countless decisions about materials,
systems and methods.
Avalon Anaheim Stadium Apartments, Anaheim CA
Architect: Withee Malcolm Architects
Photos by Michael Arden - Arden Photography
Basics of Sustainable
Development
Green design fits within the overarching objective
of global sustainable development, as defined by
the 1992 World Commission on Environment and
Development (the Brundtland commission):
“Sustainable development is development that meets
the needs of the present without compromising the
ability of future generations to meet their own needs.”
To achieve this objective, it is necessary to practice
environmental stewardship and manage renewable
resources responsibly to meet the growing needs
of the planet. Sometimes this means using less,
and often it means choosing naturally renewable
products that have a lighter footprint and come from
responsibly managed and sustainable sources.
Also fundamental to sustainable development is
the consideration and evaluation of all the potential
impacts of buildings, whether economic, social or
environmental.
Green design considers
•
Planning
•
Site development
•
Design
•
Construction
•
Maintenance
•
Decommissioning,
reuse or disposal
The Role of Green Design
Constructing and operating buildings has an immense environmental impact. Globally,
buildings are responsible for 20 percent of all water consumption, 25 to 40 percent of all
energy use, 30 to 40 percent of greenhouse gas emissions and 30 to 40 percent of solid
water generation.2
The extraction and processing of raw materials for use in buildings is also a significant
cause of environmental degradation, and these materials can be a major source of the
environmental contaminants that contribute to health problems for building occupants.
Building professionals can reduce impacts on the environment and human health in key
areas, including:
United Nations Environment Programme, Sustainable Consumption and
Production Branch. www.unep.fr/scp/bc/.
2
• Site design: Green design encourages the use of
building sites that maximize passive solar heating
and cooling, conserve natural resources such
as trees and wildlife habitat, and minimize soil
disturbance and erosion. Both location and design
can encourage the use of alternate transportation
methods such as mass transit, cycling and walking.
• Water quality, conservation and efficiency: Green
design uses on-site mechanisms such as rainwater
harvesting, water-conserving fixtures, waste water
treatment and recycling, green roofs and controlled
storm water discharge. This ensures water is used
efficiently, and reduces the burden on municipal or
other infrastructure to supply potable water, collect
and discharge storm water, and treat and dispose of
waste water.
• Energy efficiency and renewable energy: Green
design addresses building massing and orientation,
and may incorporate high levels of insulation,
capture of heating and cooling energy from
geothermal or other natural sources, renewable
energy installations (such as biomass, photovoltaics,
wind turbines or solar hot water heating systems),
energy-efficient equipment and appliances, careful
envelope design to harvest daylight, and the use
of solar shading devices, daylight and occupancy
sensors.
• Conservation of materials and resources:
Green design considers the environmental impacts
of materials and products across their entire
life cycle. It gives preference to those with low
environmental impact and embodied energy in their
extraction or manufacture; that are self finished,
non-toxic, multi-functional, durable, and easily
salvaged and recycled at the end of a building’s
service life.
• Indoor environmental quality: Green design aims
for high levels of natural ventilation and daylight
in all occupied areas of the building. It also strives
for high indoor air quality through construction
protocols aimed at eliminating airborne and surface
contaminates, and through the specification of
materials that contain no chemicals or compounds
harmful to human health.
Pocono Environmental
Education Center in Digmans
Ferry, Pennsylvania, designed by
Bohlin Cywinski Jackson, boasts
many sustainable properties
such as passive solar heating,
natural ventilation methods,
energy-efficient insulation,
day-lighting, and the use of
recycled and non-toxic materials
for construction, including gluelaminated timbers.
Left and Cover Page:
Drs Julian & Raye Richardson Apartments
San Francisco, CA
Architect: David Baker Architects
This four-story affordable housing project
provides permanent residences for lowincome, formerly homeless adults. An
infill development that remediates the site
of a collapsed freeway, the goal was to
maximize a tight location to create gracious,
environmentally sustainable homes and
community spaces. Wood was used as the
primary structural material due to its cost
effectiveness and as a symbol of nature and
renewability. It was also used throughout the
interior to add warmth, texture and variety to
private and common spaces. Designed with
long-term durability in mind, the building
rates 143 GreenPoints and surpasses
California’s strict energy standards by
15 percent.”
Life Cycle Assessment
Construction and design issues are complex, and the decisionmaking processes of green design are often hampered by a lack
of hard data on the products, processes and materials under
consideration.
Source: www.woodworks.org/
project-gallery/drs-julian-and-rayerichardson-apartments/
The best way to understand the full environmental impact of
any product is through life cycle assessment, which looks
quantitatively at all environmental impacts, not just one single
attribute, and provides an effective basis for comparing alternate
designs. Module 2 has more information about life cycle
assessment.
Understanding the full
water use
environmental impact
Life cycle assessment adds
up all the environmental
resource
use
effects of decisions and
(depletion)
processes over the life of
a product – from resource
emissions
to air
extraction to disposal
or reuse.
Green buildings
transportation
energy use
• Mitigate climate change
Life Cycle
Assessment
resource
extraction
effects
emissions
to water
solid waste
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 2
Life Cycle
Assessment
Making the Right
Environmental Choice
impartial comparison of materials and assemblies over
their entire lives. Prescriptive approaches to green
design often focus on a single characteristic, such as
recycled content, with an assumption it will yield the
greatest environmental advantage.
The choice of products used to build, renovate and
operate structures of all types has a huge impact
on the environment, consuming more of the earth’s
resources than any other human activity, and
producing millions of metric tons of greenhouse
gases, toxic emissions, water pollutants and solid
waste.
Obviously, building with the environment in mind
can reduce this negative impact. But to be effective,
decisions need to be based on a standardized,
quantified measurement system that allows an
The most widely accepted scientific method to
compare design choices and building materials
effectively is life cycle assessment (LCA). It has
existed in various forms since the early 1960s, and
the protocol for completing life cycle assessments
was standardized by the International Organization for
Standardization (ISO 14040-42) in the late 1990s.
What is Life Cycle Assessment?
Cascades Academy of Central Oregon Tumalo, OR
Architect: Hennebery Eddy Architects Inc
Photos: Josh Partee
Life cycle assessment is a performance-based
approach to assessing the impacts building choices
have on the environment. LCA can be used to
analyze impacts at every stage of its life, including:
• fossil fuel depletion
• other non-renewable resource use
• global warming potential
• water use
• acidification
• stratospheric ozone depletion
• ground level ozone (smog) creation
• eutrophication
• hazardous and non-hazardous waste
Since its inception in 1997, the Athena Sustainable
Materials Institute has focused on bringing rigorous
quantification to the pursuit of sustainability in
the built environment. Athena works with product
manufacturers, trade associations, green building
associations, and architectural and engineering
firms to help quantify environmental impacts and to
demystify and assist teams with LCA.
Designers can make informed environmental
decisions using life cycle assessment tools such
as BEES (Building for Environmental and Economic
Sustainability) and the ATHENA Impact Estimator
for Buildings or EcoCalculator. BEES evaluates the
environmental performance of individual products
whereas the ATHENA software tools deal primarily
with whole building design.
It enables an objective comparison to be made
between alternate materials and assemblies over
their lifetime, based on quantifiable indicators of
environmental impact. Life cycle assessment clarifies
the environmental trade-offs associated with choosing
one material over another and, as a result, provides an
effective basis for comparing alternate designs in
a specific geographic location.
The ATHENA Institute is also working with other
organizations to assist the integration of life cycle
assessment methodology into third-party green
building rating systems such as LEED (Leadership in
Energy and Environmental Design) and Green Globes.
Life cycle assessment considers every input and output
This diagram illustrates the general concept of life cycle
assessment, where all of the environmental inputs and outputs
emissions out
emissions out
emissions out
emissions out
Product
use or
consumption
resources
and energy in
Product
manufacture
resources
and energy in
Materials
manufacture
resources
and energy in
Raw
material
acquisition
resources
and energy in
resources
and energy in
emissions out
are measured at each stage of a product’s life.
Final
deposition;
landfill,
incineration,
recycle, or
reuse
reuse and recycle
waste out
waste out
waste out
waste out
waste out
Transportation is considered at each stage of the life cycle
Life Cycle Assessment
and Wood
Life cycle assessment studies worldwide have
consistently shown that wood products yield clear
environmental advantages over other building
materials. Wood buildings can offer lower greenhouse
gas emissions, less air pollution, lower volumes of
solid waste and less ecological resource use.
A comprehensive review of scientific literature looked
at recent research done in Europe, North America and
Australia pertaining to life cycle assessment of wood
products. It applied life cycle assessment criteria in
accordance with ISO 14044 and concluded, among
other things, that:
•
Fossil fuel consumption, the potential
contributions to the greenhouse effect and
emissions to air and water are consistently lower
for wood products compared to competing
products.
•
Wood products that have been installed and
are used in an appropriate way tend to have a
favorable environmental profile compared to
functionally equivalent products out of other
constructed materials.
Similar results were found for whole buildings in a
comparison of three hypothetical buildings of identical
size and configuration. Designed for the Atlanta
geographical area, the building was two stories in
height, had a footprint of 20,000 ft.2, a total floor area
of 40,000 ft.2, and was built on a concrete foundation
and slab. A commonly used LCA tool, the Athena
Eco-Calculator, was used to evaluate three alternative
configurations of the building – wood, concrete, and
steel. To simplify analysis, the theoretical building
was analyzed without windows, doors, or internal
partitions. Impacts associated with the steel design
as compared to the wood design were found to be
1.02 to 3.0 times greater. Comparison of the concrete
vs. wood design shows even greater differences. In
this case environmental impacts associated with the
concrete design ranged from 1.9 to 5.8 times greater
than for the wood design.
Normalized to wood value = 0.75
6
Wood Design
Steel Design
Concrete Design
5
On the cover:
The Craig Thomas Discovery
and Visitor Center,
Grand Teton National Park,
Wyoming
Architect: Bohlin Cywinski
Jackson
4
3
2
1
Green buildings
0
Fossil
Energy
Resource
Use
GWP
Acidification Eutrophication
Ozone
Depletion
Smog
potential
Source: Dovetail Partners using the Athena Eco-Calculator (2014)
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
Comparing Environmental Impact of a Wood, Steel and Concrete Home
In this graph, three hypothetical buildings (wood, steel, and concrete) of identical size and
configuration are compared. Assessment results are summarized into seven key measures
covering fossil energy consumption, weighted resource use, global warming potential, and
measures of potential for acidification, eutrophication, ozone depletion, and smog formation.
In all cases, impacts are lower for the wood design. Source: Dovetail Partners using the
Athena Eco-Calculator (2014)
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 3
Energy
Conservation
The Importance of Energy
As much as one third of the energy produced in North
America is used to heat, cool and operate buildings.
Since much of the energy consumed to build and
operate buildings comes from burning fossil fuels, this
releases a significant amount of greenhouse gases.
• Recurring embodied energy – The energy
required to maintain, upgrade or replace, and
eventually dismantle and dispose of, materials
and components throughout the service life of the
building.
Types of Energy
Three types of energy are considered through life
cycle assessment:
• Operating energy – The energy required to heat,
cool, and ventilate the building, and provide
hot water, lighting and power for services and
equipment on an ongoing basis.
• Initial embodied energy – The energy required
to extract and process raw materials, fabricate
or manufacture them into building components,
transport them to site, and install them into the
building.
Energy Consumption
in Buildings
Wood has low thermal conductivity and good
insulating properties, and light wood-frame
technology lends itself readily to the construction
of buildings with low operating energy.
A study conducted by the Consortium for Research on
Renewable Industrial Materials (CORRIM)1 compared
the environmental impact of a wood-frame house
typical for the Minneapolis/St. Paul metropolitan area
to an otherwise identical steel-frame house. CORRIM
also compared a wood-frame house typical of the
Atlanta area to an otherwise identical concrete block
house. In both cases, life cycle assessment from
raw material extraction through building construction
showed lower embodied energy and global warming
potential for the wood framed homes. Compared to
wood construction, steel and concrete embody and
consume 17 and 16 percent more energy, and emit 26
and 31 percent more greenhouse gases.
Mass timber construction techniques such as crosslaminated timber and glulam have the potential to
increase the thermal mass of a building. An increase
Wood is low in embodied energy. It’s produced
naturally and requires far less energy than other
materials to manufacture into products. Much of the
energy used to process wood in Canada, such as
the energy needed for kiln drying, also
comes from renewable biomass,
including chips and sawdust–
a self-sufficient, carbonneutral energy
source.
in thermal mass helps to moderate temperature
fluctuations within a building; increasing occupant
comfort and reducing operational energy consumption
over the life cycle. The addition of thermal mass
can be particularly effective in cooling dominated
climates, such as the southwest United States desert
areas where there are large day-night temperature
variations.
The wood industry is investing in research to increase
energy efficiency through continual improvement,
developing building systems that offer greater air
tightness, less conductivity and more thermal mass
where appropriate—including prefabricated systems
that contribute to the low energy requirements of
Passive House and Net Zero designs.
In many scenarios, the variations in operating energy
consumption between otherwise identical wood,
steel and concrete buildings are small, and they are
becoming less significant as insulation levels increase
and building envelope technology becomes more
sophisticated. However, the reverse is true with
embodied energy.
Perez-Garcia, J., Lippke, B., Briggs, D, Wilson, J., Bowyer, J., and Meil, J. 2005. The
Environmental Performance of Renewable Building Materials in the Context of Residential
Construction. Wood and Fiber Science, Vol. 37, pp. 3-17.
1
Green design reduces both
operating and embodied
energy. A typical concrete
house has nearly as much
energy embodied in the
materials as it takes to run
55%
Operating
45%
Embodied
the house for 20 years.
The Evolving Relationship between
Operating and Embodied Energy
In the U.S., up until the beginning of the 21st century,
the environmental impacts of buildings were seldom
considered in conception and design. Operating
energy was typically considered only to the extent
required by code. At that time energy consumption
associated with US buildings was high compared
to most other developed countries. Since that time,
interest in high-performance buildings has come into
the mainstream, driven primarily by the emergence
of a number of green building programs. One result
is that many of the commercial buildings constructed
today are much more energy efficient than only
several decades ago, with use of operating energy
in the best performing buildings 50% or less of
average1,2. Attention is now also being given to
embodied energy, in part because the energy required
to create a building becomes increasingly important
as operating energy efficiency increases2. Studies
referenced within the U.S. LCI Database Project3
consistently show that buildings built primarily with
wood have a lower embodied energy than those built
primarily of brick, concrete or steel. Extensive use
of wood in construction of the new David and Lucile
Packard Foundation headquarters building resulted
in an estimated 25 percent reduction in embodied
energy compared to concrete and steel alternatives4.
General Services Administration. 2011. Green Building Performance – A PostOccupancy Evaluation of 22 GSA Buildings. U.S. Government, GSA Public Buildings
Service. (http://www.gsa.gov/graphics/pbs/Green_Building_Performance.pdf)
1
Fish, D. 2012. (by)Metrics (by) Design: Building for Endurance. University of
Washington, College of Architecture, MS Thesis. (https://digital.lib.washington.edu/
xmlui/handle/1773/22681)
2
National Renewable Energy Laboratory. 2014. US LCI Database. U.S. Department of
Energy, Office of Energy Efficiency and Renewable Energy. (http://www.nrel.gov/lci/ )
3
Urban Land Institute. 2013. The David and Lucile Packard Foundation Building: Best
Practice Case Study. ULI San Francisco District Council Sustainability Committee.
4
(http://sf.uli.org/wp-content/uploads/sites/47/2013/05/ULI-CaseStudy-PackardBuildingFINAL.pdf)
Embodied Plus Operating
Energy Over 60 Years
Wood buildings of all sizes and types can be easily
designed to meet or surpass energy standards in any
climate.
Energy performance depends more on insulation, air
sealing and other factors than the choice of structural
material. Most new homes are insulated well, so they
tend to have essentially comparable energy performance.
However, embodied energy is very much affected by
structural material so it is important to look at both
operating and embodied energy when evaluating
structural materials in terms of energy consumption.
Total Kilojoules
90,000,000
60,000,000
30,000,000
Heating
energy
Cooling
energy
0
Wood House
Steel House
A Wood Building
is Easier to Insulate
While a good thermal assembly can be created with any
structural material, wood is a better natural insulator than
steel and concrete.
Due to its cellular structure and lots of tiny air pockets, wood is
400 times better than steel and 10 times better than concrete in
resisting the flow of heat. As a result, more insulation is needed
for steel and concrete to achieve the same thermal performance
as with wood framing.
This graph shows the energy performance in two buildings near
Chicago. The 2002 study prepared by the National Association
of Home Builders Research Center Inc.6 compared long-term
energy use in two nearly identical side-by-side homes, one
framed with conventional dimensional lumber and the second
framed with cold-formed steel. It found the steel-framed house
used 3.9 percent more natural gas in the winter and 10.7 percent
more electricity in the summer.
On the cover:
Project: The Crossroads,
Good Manufacturing Practices Facility,
Madison, Wi
Photo: C&N Photography, Inc.
Engineer: Ewingcole, Philadelphia, Pa
Green buildings
The steel building has significantly more insulation than the
wood building yet it still did not perform as well. It also has more
embodied energy, which is not reflected in the graph.
• Mitigate climate change
The data was measured for one year and also simulated with
software in order to normalize and validate results. Both houses
have fiberglass insulation between the studs.
• Reduce waste
6
NAHB Research Centre Inc, 2002: ‘Steel versus Wood: Long Term Thermal Performance Comparison.
• Use less energy and water
• Use fewer materials
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 4
Resource
Conservation
Seattle District headquarters for the U.S. Army Corps of Engineers is a LEED Gold project which
was partially funded through the U.S. GSA’s Design Excellence Program. All of the wood used in
the project was salvaged from a 1940s-era warehouse that previously occupied the site—a total of
200,000 board feet of heavy timber and 100,000 board feet of 2x6 tongue and groove roof decking.
Federal Center South – Building 1202 Seattle, WA
Architect: ZGF Architects LLP Photos: Benjamin Benschneider
Using Resources Wisely
Responsible resource management is essential if we
are to reach the goal of true sustainable development.
Sometimes this will mean using less, but it will always
mean choosing products with the lightest carbon
footprint possible.
When it comes to building construction and
renovation, this means identifying materials,
manufacturing processes and design strategies that:
• minimize the use of non-renewable resources
• minimize waste during the extraction and manufacturing process
• minimize the use of fossil fuel energy during extraction and manufacturing
• use products that are flexible, adaptable and durable
• enable the reuse of materials and products from dismantled buildings
• recycle materials only when no longer fit for their original purpose.
A Closer Look at
1000%
Recycled Content
Wood
Steel
800%
Hypothetical Steel
This bar chart compares
life cycle assessment
environmental profile of two
standard structural postand-beam systems, and one
hypothetical steel structure
with 100 percent recycled
920
884
600%
545
506
400%
333
270
200%
0
Source: FPInnovations, calculated using the
ATHENA Impact Estimator for Buildings.
224
161
100
content.
251
Embodied
Energy
100
100
Waste
58
Air
Pollution
100
149
Water
Pollution
100
Greenhouse
Gas
Emissions
229
182
100
74
Resource
Use
100
Water
Use
Benefits of Wood
Selecting wood building products offers the following
advantages related to resource conservation:
1.Wood is 100 percent renewable. When grown and
harvested according to internationally recognized
sustainable forest management practices, it is
the only major construction material that can be
regenerated for the benefit of future generations.
2.The portion of harvested wood volume entering
primary processing mills in North America that is
converted to marketable products, or converted
to useful energy, is near 100%. In other words,
the wood waste at these mills is near 0 percent;
therefore, in terms of wood use, these are zerowaste facilities. Secondary processing plants are
similarly diligent in utilization of raw materials1.
3.Wood has the least embodied energy of all
major building materials2. In other words, the
energy consumed to grow, harvest, transport
and manufacture wood products is less than for
other products. Not only does wood require less
energy to manufacture into products, half of that
is generated from wood waste such as chips
and sawdust. Burning wood waste for energy is
considered carbon neutral because it only releases
the carbon sequestered in the wood during the
growing cycle.
4.Wood is versatile and adaptable. A building’s
structural design and spatial subdivision determines
its ability to be flexible in use, and adaptable so
it can meet new requirements. Separating these
functions makes it easier to reconfigure the
space. Wood lends itself to this design approach,
especially through the use of post-and-beam
structures (in solid sawn lumber or engineered
wood) and non-load-bearing partitions made up of
smaller members (either solid laminated or in stud
frame construction).
5.Wood lends itself to dismantling, a fact borne out
by the continued predominance of wood and wood
products in the architectural salvage market. It can
generally be reclaimed without diminishing its value
or usefulness for future applications. This contrasts
with materials like concrete, which is usually
crushed for future use as aggregate or ballast, or
brick, which can be easily damaged when cleaned
for reuse, and which can rarely be reassembled with
the original precision.
6.There is growing interest in wood recycling
during deconstruction. Many wood products
and materials can be reclaimed and reused for
the same or similar purpose with only minor
modifications. Lumber can be remilled and made
into other products, such as flooring, cladding,
window and door frames, or millwork and trim.
Some communities have enacted ordinances to
require materials from construction and demolition
be recovered. For example, San Diego County,
California requires that 90 percent of insert
materials and 70 percent of all other materials
(including wood cabinets, doors, windows, pallets,
and unpainted wood) be recovered from C&D
projects.3
Bowyer, J., Bratkovich, S., and Fernholz, K. 2012. Utilization of Harvested Wood
by the North American Forest Products Industry. Dovetail Partners. 8 October 2012.
Available at: www.dovetailinc.org
1
Werner, Frank and Richter, Klaus, Scientific Journals April 2007: Wooden Building
Products in Comparative LCA: A Literature Review.
2
Howe, J., Bratkovich, S., Bowyer, J., Frank, M., and Fernholz, K. 2013. The Current
State of Wood Reuse and Recycling in North America and Recommendations for
Improvements. Appendix E: Case Studies. Dovetail Partners. May 2013. Available
at: www.dovetailinc.org
3
On the cover:
Tillamook Forest Center, Oregon
Architect: The Miller/Hull
Partnership, LLP
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Jungers Culinary Center, Bend, OR
Architect: Yost Grube Hall Architecture
Photo courtesy of RealCedar.com
Building
Greenwith
Wood
MODULE 5
Durability and
Adaptability
The Service Life of Buildings
In North America, we have historically chosen not to exploit the potential longevity of buildings, instead
assigning a higher priority to other factors. As a consequence, with the exception of the few that are
designated ‘post-disaster’ structures most buildings have a service life of less than 50 years.
Most structures are demolished because of external forces such as zoning changes and rising
land values – often the building fabric itself may still be in good condition. When one
considers the embodied energy in these structures and the implications of material
disposal, it is clear that these premature losses have a considerable negative
environmental impact.
New buildings can be designed for flexibility and adaptability, and the
full service life can be extracted from building materials if they are
reclaimed and reused as much as possible.
In this way, architects
can assume the role
of curators, not
just creators,
of the built
environment.
Durability of Materials
and Structures
Designers can get maximum performance and service
life out of every building material as long as they
understand the necessary steps. Improperly detailed
masonry and concrete may spall or crack, steel may
rust, and wood may deteriorate. In each case, this
compromises the integrity of a building and reduces
its life expectancy.
Used properly, all of these materials are inherently
durable and can endure for decades or even
centuries. The most ancient wood buildings still in
existence include eighth century Japanese temples,
11th century Norwegian stave churches, and the many
medieval post-and-beam structures of England and
Europe. These buildings endure partly because of
their cultural significance, and partly because they
were built and maintained properly.
For example, long posts supporting the multi-tiered
roofs of stave churches were air dried for up to two
years to prevent shrinkage and distortion after they
were installed. Wood foundation beams were laid on
a gravel-filled trench to protect the structure from
long-term contact with water. Vertical planked walls
were protected from the weather by large overhanging
eaves, and shingle roofs were steeply pitched to shed
rain and snow.
Although we need a more sophisticated
understanding of building physics to ensure the
integrity and longevity of materials and structures,
the same basic principles still apply.
The Cathedral of Christ The Light in Oakland,
California, (on the cover) is an extraordinary timber
cathedral designed to last 300 years using a unique
structural system. Designed by Skidmore, Owings &
Merrill LLP (SOM), the soaring 36,000-square-foot,
1,500-seat structure replaces another cathedral
Continued on next page....
Post-disaster Design
While all buildings are at risk of experiencing damage
during natural disasters, wood has a number of
characteristics that make it conducive to meeting
the challenges of seismic- and wind-resistive design.
Light weight. Wood-frame buildings tend to be
lightweight, reducing seismic forces, which are
proportional to weight.
Ductile connections. Multiple nailed connections
in framing members, shear walls and diaphragms of
wood-frame construction exhibit ductile behavior
(the ability to yield and displace without sudden
brittle fracture).
Redundant load paths. Wood-frame buildings tend
to be comprised of repetitive framing attached with
numerous fasteners and connectors, which provide
multiple and often redundant load paths for resistance
to seismic and wind forces. Building codes also
Stella
Marina del Rey, CA
Architect: DesignARC
Photo: Lawrence Anderson
The luxury Stella development in California includes four
and five stories of wood-frame construction over a shared
concrete podium. It was designed to meet requirements
for Seismic Design Category D.
prescribe minimum fastening requirements for the
interconnection of repetitive wood framing members;
this is unique to wood-frame construction and
beneficial to a building’s performance.
The Barn at Fallingwater, designed by Bohlin
Cywinski Jackson, is a renovated
19th-century barn with a 1940s dairy barn
addition. This adaptive reuse project is
immediately adjacent to Frank Lloyd Wright’s
Fallingwater and is the first phase of a conference
complex for Western Pennsylvania Conservancy.
The Barn’s interior is rich with recycled and
salvaged materials that celebrate the region’s
agrarian heritage. More than 80 percent of the
construction debris was recycled.
.....Continued from previous page
destroyed during a 1989 earthquake. Architecturally
stunning, the new building features a space-frame
structure comprised of a glulam and steel-rod
skeleton veiled with a glass skin. Given the close
proximity of fault lines and non-conformance of the
design to a standard California Building Code lateral
system, the City of Oakland hired a peer review
committee to review SOM’s design for toughness
and ductility. Through the use of advanced seismic
engineering, including base isolation, the structure has
been designed to withstand a 1,000-year earthquake.
Engineers were able to achieve the appropriate
structural strength and toughness by carefully defining
ductility requirements for the structure, using threedimensional computer models that simulate the
entire structure’s nonlinear behavior, testing of critical
components relied on for seismic base isolation and
superstructure ductility, and verifying their installation.
The Fulton County Stadium in Atlanta, Georgia,
was imploded in 1997 – just 32 years after
it was built and shortly after it had been
refurbished to host the baseball events for
the 1996 Olympics. It is a clear example of
premature demolition because the building
could not meet changing needs.
Left image:
Islandwood Environmental
Interpretive Center,
Bainbridge Island, Washington
Mithun Architects +
Designers + Planners
The Center was designed so
materials can be reclaimed
at the end of the structure’s
service life.
Flexibility and Adaptability
Designing for flexibility and adaptability is also critical to secure
the greatest value for the net energy embodied in building
materials. Wood structures are typically easy to adapt to new
uses because the material is so light and easy to work with.
The inherent structural redundancy in light-weight wood-frame
structures provides many opportunities for adaptation, while
post-and-beam structures provide complete flexibility in the
reconfiguration of non-load bearing partitions.
Wood also lends itself to dismantling. The Islandwood
Environmental Interpretive Center on Bainbridge Island in
Washington state has a post-and-beam frame so partitions can
be non-load-bearing, with fully demountable bolted connections
to permit reclamation of the complete structure at the end of
its service life. In contrast to other materials, reclaimed wood
can often be reused for its original purpose (e.g., as structural
members), with little or no loss of value.
On the cover:
Cathedral Of Christ The Light
Oakland, CA
Architect: Skidmore, Owings & Merrill LLP
Award Category: Landmark Wood Design
Photos: Timothy Hursley & Cesar Rubio
Architecturally stunning, the Cathedral of Christ The
Light features a space-frame structure comprised of
a glulam and steel-rod skeleton veiled with a glass
skin. Twenty-six, 110-foot glulam Douglas-fir ribs
curve to the roof to form the framework for the
sanctuary superstructure. A total of 724 closely
spaced glulam “louver” members interconnect and
provide lateral bracing for inner rib members. Green
ceramic fritted glass panels jacket the Cathedral’s
outer shell to insulate the building, reduce glare, and
change the quality of light throughout the day and
seasons.
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 6
Health and
Well-being
Building Impacts
on Human Health
Green building objectives are broader than just environmental effects,
and have come to embrace human health issues as well, including
performance. In the developed world where people spend much of their
time inside buildings, the design of the indoor environment is of critical
importance to human health.
Within the context of green design, measures frequently explored
for a better indoor environment include:
• monitoring of carbon dioxide levels
• ventilation effectiveness
• management of dust and
contaminants during construction
• control of indoor chemical
and pollutant sources
• personal control of
environmental systems
• provision of daylight and views.
Yountville Town Center
Yountville, CA
Siegel & Strain Architects
Designing for Human
Well-being
sense of well-being when indoors. This can be
achieved through access to daylight or views, or by
providing a visual or tactile connection with natural
materials such as wood and stone.
Health and well-being embraces both physical health,
and the psychological aspects of human performance.
For many years, research has shown the human
health benefits of forests. The benefits of time
spent in forests include reduced stress, lower blood
pressure, and improved mood. Medical research
shows exposure to forests can boost our immune
system and may even correlate to lower cancer rates.
The benefits of forests are strongly recognized in
some cultures. In Japan, the term “forest bathing”
refers to time spent in the forest atmosphere and
is encouraged by public policy. New research is
beginning to show that the visible use of wood in
buildings provides human health benefits as well.
Over time, physical issues have been dealt with
incrementally through legislation that has banned
the use of toxic or otherwise dangerous substances
in buildings. In addition, new standards have been
introduced to ensure adequate ventilation, reduce
condensation and inhibit the growth of molds and
mildew.
Designers are also interested in potential
psychological and related physiological benefits of
environmental design factors. For example, intuition
tells us that a connection to nature improves our
Fell, David. 2013. Wood and Human Health. FPInnovations.
https://fpinnovations.ca/MediaCentre/Brochures/Wood_Human_Health_final-single.pdf .
A recent study at the university of British Columbia
and FPInnovations1 identified a link between the use
1
Continued on next page....
.....Continued from previous page
of wood and human health. The study compared
the stress levels of participants in different office
environments with and without wood finishings.
The results found that “Stress, as measured by
sympathetic nervous system (SNS) activation, was
lower in the wood room in all periods of the study.”
Studies have shown that SNS activation increases
blood pressure and heart rate while inhibiting
digestion, recovery, and repair functions in the
body. People that spend a lot of time in a state
of SNS activation can show physiologically and
psychologically impacts. The use of visual wood
surface can reduce SNS activation and promote
health in building occupants.
Wood and Interior
Air Quality
Dust and Particulates
Solid wood products, particularly flooring, are often
specified in environments where the occupants are
known to have allergies to dust or other particulates.
Wood itself is considered to be hypo-allergenic; its
smooth surfaces are easy to clean and prevent the
buildup of particles that are common in soft finishes
like carpet.
Off-gassing
Interior wood panel products, such as particleboard,
medium density fibreboard (MDF), and hardboard,
The Herrington Recovery Center in Milwaukee,
Wisconsin, is one example of designing with wood
and natural environments to support the mission of
the facility. Rooms maximize views of the outdoors
and interior uses of wood include woodwork, ceilings,
soffits, and other elements.
The growing knowledge of the health benefits
of building with visual wood surfaces is being
incorporated into healthcare environmental to
support patient recovery, school environments
to support student learning, and offices to support
employee health.
were once identified as having a negative impact
on indoor air quality because of their use of
urea-formaldehyde (UF) glues. The concern was
that, if panels were left unsealed, volatile organic
compounds would be released into the air.
In 2004, the Composite Panel Association (CPA)
(www.pbmdf.com) introduced an Environmentally
Preferable Product (EPP) Certification Program to
lower formaldehyde emissions from wood-based
panels intended for interior use. EPP-designated
products have since been third-party certified
as complying with the environmental criteria
referenced in the U.S. Environmental Protection
Agency’s Guidelines for Environmentally Preferable
Purchasing.2 Compliance requires rigorous quarterly
audits at the manufacturing site and independent
third-party product emission testing.
The Composite Panel Association’s EPP Certification
Program is the first EPP certification program
accredited by the American National Standards
Institute (ANSI).
Some manufacturers also produce formaldehydefree panel products, made with an urethane-type
(MDI) resin. Once cured, MDI-based wood panel
products are very stable, without measurable offgassing.
Humidity Control
The use of wood products can also improve indoor
air quality by moderating humidity. Acting like a
sponge, the wood absorbs or releases moisture in
order to maintain equilibrium with the adjacent air.
This has the effect of raising humidity when the air
is dry, and lowering it when the air is moist – the
humidity equivalent of the thermal flywheel effect.
Wood panels certified to CPA’s EPP Certification Program must demonstrate that
they are made from 100% recycled or recovered fibre and meet emissions of maximum
0.2 parts per million of formaldehyde.
2
Left Image:
U.S. Land Port of Entry Warroad, MN
Julie Snow Architects, Inc. Minneapolis, MN
On the cover:
Sema 4,
Leucadia, CA
Brian Church Architecture, CA
Photo courtesy of RealCedar.com
Sources:
Barton, J., Pretty, J. (2010). What is the Best Dose of Nature and Green Exercise for Improving
Mental Health? A Multi-Study Analysis. Environmental Science and Technology. 44: 3947-3955.
http://www.ncbi.nlm.nih.gov./pubmed/20337470.
Fell, David. (2013). Wood and Human Health. FPInnovations.
https://fpinnovations.ca/MediaCentre/Brochures/Wood_Human_Health_final-single.pdf .
http://woodworks.org/wp-content/uploads/2014-SoCal-WSF-Fell-Healthy-Buildings-The-Case-forVisual-Wood.pdf
Gies, E. (2006). The Health Benefits of Parks. The Trust for Public Land. http://www.tpl.org/
publications/books-reports/park-benefits/the-health-benefits-of-parks.html.
Lee, J., Park, B.-J., Tsunetsugu, Y., Ohra, T., Kagawa, T., Miyazaki, Y. (2011). Effect of forest bathing
on physiological and psychological responses in young Japanese male subjects. Public Health. 125(2):
93-100. http://www.sciencedirect.com/science/article/pii/S0033350610003203.
Li, Q. (2010). Effect of forest bathing trips on human immune function. Environmental Health and
Preventative Medicine. 15(1): 9-17. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793341/.
Li, Q., Kobayashi, M., Kawada, T. (2008). Relationships Between Percentage of Forest Coverage and
Standardized Mortality Ratios (SMR) of Cancers in all Prefectures in Japan. The Open Public Health
Journal. 1: 1-7. http://www.benthamscience.com/open/tophj/articles/V001/1TOPHJ.pdf.
Wood in Healthcare: A Natural Choice for Enhancing Human Well-Being. (2012). Naturally: Wood
http://www.naturallywood.com/sites/default/files/Wood-in-Healthcare.pdf
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 7
Social & Economic
Sustainability
Sustainable Development
Green building supports a built environment that is socially,
environmentally and economically responsible. These are
the three pillars of sustainable development.
While it is important to promote environmental sustainability,
there is also a need to consider social and economic issues.
Buildings must be designed with people in mind – this will
lead to thriving and vibrant communities.
SUSTAINABLE
Environment
Economic
Social
Cascades Academy of Central Oregon Campus
Architect: Hennebery Eddy Architects, Inc.
Photographer: Josh Partee
Meeting Social Needs
Social sustainability relies on a collaborative approach
to building and community development, one that
involves all stakeholders, reinforces social networks,
and allows people of every age and ability to reside
and participate in their community throughout their
life. Sustainable communities make it easier for
people to travel by foot, bicycle and mass transit, and
they bring together residential, commercial and retail
development.
The objective of green design is to create
communities where people will want to live
and work now and in the future. Where appropriate,
there should be preference given to renewable and
recyclable materials that are regionally harvested or
manufactured, and can be installed and maintained by
local labour.
Once again, life cycle assessment has a key role
to play in identifying the most appropriate product
choices. There may be times when local materials
are not the most environmentally sound choice; and
it may be better to import products that have lower
extraction, processing and disposal impacts.
Meeting Economic Needs
U.S. forestry regulations,
best management practices,
monitoring and training programs
assure that products are
harvested responsibly.
A green design may cost more but often
saves operating costs throughout the life of
the building – through more efficient lighting
and better windows, smaller and less costly
HVAC, better use of materials, and reduced
demolition costs. A green building is also
likely to maintain a higher value.
A 2009 report by the U.S. General Services
Administration studied 12 sustainably
designed buildings and found they not only
cost less to operate and have excellent
energy performance, but that occupants are
more satisfied with the overall building than
those in typical commercial buildings.1
While it is often hard to quantify, studies
show that environmental air quality
improvements can actually improve
performance and productivity, and may
reduce the time lost to illness. In Nevada,
a post office was renovated at a cost of
$300,000 to lower the ceiling and install
energy-efficient lighting. It was estimated
that energy savings would pay back the
total cost in about 13 years – and that
productivity gains through improved
employee efficiency and reduced errors
would return the full cost in less than a year.
Assessing Green Building Performance. A Post Occupancy Evaluation of 12 GSA Buildings. Pacific Northwest National Laboratory (2008)
www.gsa.gov/graphics/pbs/GSA_Assessing_Green_Full_Report.pdf
1
Responsible Forest
Products
Builders can use their buying power to
improve forest management by choosing
wood products they know are from legal,
sustainable sources. This demonstrates their
corporate social responsibility and shows
customers they care about the environment.
Illegal logging is an urgent global problem that
leads to the loss of wildlife habitat and public
revenues. Lower prices for illegal forest products
distort global markets and discourage sustainable
forest management.
Private and public procurement policies are
increasingly requesting proof that
forest products are derived from
known and legal sources.
Through its comprehensive governance structures, North America is a world leader
in forest products that are harvested legally and sustainably. Forest certification
systems used in North America also contribute to assuring buyers as evidence of
these values.
On the cover:
Cascades Academy of Central Oregon Campus
Architect: Hennebery Eddy Architects, Inc.
Photographer: Josh Partee
Photographer: Michael Bednar
Community
Economic Benefits
Green buildings
In the United States, forest products provide economic
opportunities for people in communities across the
country. About one million workers are employed in
the forest products sector. Forest products account for
approximately six percent of the total U.S. manufacturing
GDP and is among the top ten manufacturing sector
employers in 48 states. Forest products in the U.S.
generate over $200 billion a year in sales and about
$54 billion in annual payroll.
• Use less energy and water
Source: USDA Forest Service. Accessed 4/15/14. http://www.fs.fed.us/research/forest-products/
• Mitigate climate change
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 8
Transportation
Effects
Looking at the
Complete Picture
Photographer: Michael Bednar, Bednar Photo
While a building’s operation over time has
the greatest environmental impact, there
is also energy consumed in extracting,
manufacturing and transporting the materials
and components used for the building
construction, installing them, and their
ongoing maintenance. In combination, these
energy inputs are referred to as embodied
energy.
Calculating the amount of embodied
energy is a complex issue. Not all green
building rating systems measure embodied
energy, but some offer credits if life cycle
assessments are carried out to determine
the impact building material choices have on
embodied and operating energy.
There may be times when sourcing local
products yields the most environmental
benefit. But the decision should not be
based on one factor alone, such as
transportation impacts. Other aspects of
embodied energy – and issues such as
pollution or environmental degradation –
may be of far greater significance in product
selection than transportation energy. Life
cycle assessment takes away much of the
guesswork by calculating outcomes based
on quantifiable indicators.
Life cycle assessment accounts for the effects of transportation mode
and not just distance. A product traveling a long distance using a
highly efficient transportation method can actually have a smaller
transportation footprint than a closer product traveling inefficiently.
Photographer: Moresby Creative
Deciding When to Buy Locally
It is natural to expect that locally sourced products
would be more environmentally responsible than
those shipped a great distance. But this is usually
based on the assumption that transportation energy
contributes a lot to the overall energy equation – and
life cycle assessment can prove that this is usually
not the case.
While buying local may help the local economy,
it is not necessarily the best environmental choice.
In many cases, transportation energy is a very small
component of overall energy consumption.
For example, the figure below illustrates those
activities that contribute to the energy embodied in
a completed structure. A recent study conducted by
the EPA1 found that in a single family wood-framed
residential home in the United States, transportation
energy accounts for about 8 percent of the total
embodied energy in the building prior to occupancy
(i.e. up to the completion of assembly). Energy used
to extract raw materials, convert them to useful
products, and construct the building accounts for
the remainder.
When operational energy (that used for heating and
cooling and all other uses during occupancy) is also
included in life cycle calculations, embodied energy
through completion of building assembly accounts
for about 8 percent of total energy. When building
maintenance through the life of a structure is also
considered (replacement of shingles, painting, etc.)
total embodied energy can account for 20-22 percent
of total life cycle energy. Life cycle assessment
ensures that all aspects of energy use are considered,
enabling materials selection decisions based on
sound knowledge.
Haynes. 2013. Embodied Energy Calculations within Life Cycle Analysis of Residential
Buildings. (http://etool.net.au/wp-content/uploads/2012/10/Embodied-Energy-PaperRichard-Haynes.pdf)
USEPA. 2013. Analysis of the Life Cycle Impacts and Potential for Avoided Impacts
Associated with Single Family Homes. EPA 530-R-13-004.
(http://www.epa.gov/waste/conserve/imr/cdm/pdfs/sfhomes.pdf)
1
Primary Resource Extraction
Transport Unfinished Product
Manufacturing Energy
Primary
Energy
Delivered
Energy
Transport Final Product
Assembly
Maintenance (Recurring)
Demolition / Recycling
Embodied
Energy
Green design requires
careful choices. Life cycle
assessment can help
determine whether a product
coming from a sustainably
managed forest versus a
rapidly renewable product
that is high in processing
emissions and transportation
emissions is the better choice.
The best green choice is…?
On the cover:
Pocono Environmental Education Center,
Dingman’s Ferry, Pennsylvania
Architect: Bohlin Cywinski Jackson
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
MODULE 9
Climate Change
Climate Change: Causes and Consequences
The Fourth Assessment Report, released by the
Intergovernmental Panel on Climate Change in
2007, states: “Warming of the climate system is
unequivocal, as is now evident from observations
of increases in global average air and ocean
temperatures, widespread melting of snow
and ice and rising global average sea level.”
systems that determine climate, but some of the
trends are already clear:
The consequences of climate change are difficult to
predict because of the complexity of environmental
•
Using Wood Can Help
Tackle Climate Change
the same time, provide products that meet society’s
needs for timber, fiber and energy. A stable market for
forest products encourages landowners to manage
forests sustainably rather than converting them to
other uses such as agriculture or urban development.
•
•
To mitigate climate change, it is necessary to reduce
greenhouse gas emissions and store more carbon.
A well-managed forest can do both.
As trees grow, they absorb carbon dioxide and store
it. When they decompose or burn, much of the stored
carbon is released back into the atmosphere, mainly
as carbon dioxide, and some of the carbon remains
in the forest debris and soils.
Securing the Future, a 2005 United Kingdom
government strategy for sustainable development
stated: “Forestry practices can make a significant
contribution by reducing greenhouse gas emissions
through increasing the amount of carbon removed
from the atmosphere by the national forest estate,
The Carbon Bank: Wood and Forest Timeline
800
Carbon (metric tons/hectare)
Wood products continue to store
much of the carbon absorbed during
the tree’s growing cycle, while the
regenerating forest once again begins
the cycle of absorption. Manufacturing
wood into products also requires far
less energy than other materials, and
most of that comes from residual
biomass (such as bark and sawdust).
Changes in natural habitats will result in the loss
of plant and animal species.
Species that carry tropical diseases, such as
mosquitoes (malaria), will spread and settle into
new areas.
Sea levels will continue to rise, with catastrophic
results for those living in coastal or river delta
areas or low-lying land.
700
600
500
400
300
Carbon in the forest
Carbon in wood products
Avoided carbon emissions
(by substituting wood for concrete)
l un
thetica
Hypo
d
manage
forest
200
100
Michael Malinowski of AIA Applied
0
Architecture, Inc. in Sacramento
2040
2080
2100
2140
2020
2120
2060
2160
2000
California is an advocate for wood
Years
in mixed use and podium design.
The Carbon Bank: Wood and Forest Timeline1 This graph shows the movement of carbon from
His background includes extensive
one pool to another. As we create more and more long-lived wood products, the balance in our
experience in architectural design,
account goes up and up.
historic adaptive reuse, value
engineering, permit streamlining, and
by burning wood for fuel, and by using wood as a
getting to yes in the approval process.
substitute for energy-intensive materials such as
“Wood construction can help maximize value to the
concrete and steel.”
community, the environment and the development
Sources:
team,” says Malinowski.
Adapted from graphs in “Forests, Carbon and Climate Change: A Synthesis of Science
Findings,” 2006, Oregon Forest Resource Institute.
In a 2007 report, the Intergovernmental Panel on
Climate Change Working Group III pointed out that
forests remove carbon from the atmosphere and, at
Using a Wood Podium in Mixed-Use Design: An Architectural Case Study http://
woodworks.org/wp-content/uploads/2014-Mar-TX-WS-Malinowski-Wood-PodiumMixed-Use-Design.pdf
Michael Malinowski, Applied Architecture, Inc. http://woodworks.org/wp-content/
uploads/2014-Mar-TX-WS-Malinowski-Wood-Podium-Mixed-Use-Design.pdf
Deforestation in developing
countries is a leading
contributor to CO2 emissions.
Managing Forests to
Mitigate Climate Change
Trends in US Forestland Area 1630-2012
1200
1000
800
Million Acres
When a tree is cut down, 40 to 60 percent
of the carbon stays in the forest, and the
rest is removed in the logs, which are
converted into forest products.1 Some
carbon is released when the forest soil is
disturbed during harvesting, and the roots,
branches and leaves left behind release
carbon as they decompose.
wildfires. “Recent megafires in California and the West
have destroyed lives and property, degraded water
quality, damaged wildlife habitat, and cost taxpayers
hundreds of millions of dollars,” said David Edelson,
600
400
The amount of carbon dioxide released
through harvesting is small compared
200
to what is typically experienced through
forest fires and other natural disturbances
0
such as insect infestations and disease.
The United States has over 750 million
acres of forestland. Forests cover about
one-third of the nation, and the total forest area in the
United States has been stable for about 100 years.2
Wildfires can be a significant threat to forests and the
people the live near them. Recent research has found
that proactive forest harvesting and management
techniques can reduce the risk of high-severity
Does harvesting in Canada’s forests contribute to climate change? Canadian
Forest Service, 2007, www.sfmcanada.org/images/Publications/EN/CFS_
DoesHarvestingContributeToClimateChange_EN.pdf
1
1630
1907
1920
1938
1953
1970
1630
1977
1987
1992
1997
2009
2012
Source: USDA - Forest Service, 2013
Sierra Nevada Project Director with The Nature
Conservancy. “This study shows that, by investing
now in Sierra forests, we can reduce risks, safeguard
water quality, and recoup up to three times our initial
investment while increasing the health and resilience
of our forests.”3
2
National Report on Sustainable Forests - 2010, USDA Forest Service
Source of quote: Sierra Star. New study could save on future fires. April 10, 2014.
Accessed 4/15/14. http://www.sierrastar.com/2014/04/10/67208/new-study-could-saveon-future.html
3
Greenhouse Gases,
Carbon, and Forests
The Greenhouse Effect
The glass panels of a greenhouse let in light and keep
heat from escaping, providing warmth for the plants
growing in them. A similar process occurs when the
sun’s energy reaches the Earth – some is absorbed by
the Earth’s surface, some radiates back into space,
and some is trapped in the Earth’s atmosphere, which
keeps the planet warm enough for life to flourish. This
is called the greenhouse effect.
The carbon cycle affects the amount of energy
trapped in the atmosphere. Plants absorb carbon
dioxide and emit oxygen during photosynthesis;
oceans also absorb carbon dioxide. Humans and
other animals inhale oxygen and exhale carbon
dioxide. Carbon dioxide is emitted when substances
decompose or burn.
Scientists agree this natural balance has been upset.
The biggest human cause is the amount of carbon
dioxide being released into the atmosphere through
the burning of non-renewable fossil fuels, such as oil,
natural gas or coal. Carbon dioxide accounts for more
than 75 percent of total greenhouse gas emissions.
Close to eight billion tonnes of carbon dioxide are
emitted every year – most of this through fossil fuel
combustion and deforestation in tropical regions.
Some is absorbed by water bodies, some is absorbed
by forests – and some is emitted into the atmosphere.
If too much carbon is emitted, it causes the
atmosphere to trap more heat, warming the planet.
Rising temperatures may, in turn, produce changes in
weather, sea levels, and land use patterns, commonly
referred to as climate change.
Forests and the Carbon Cycle
Quantifying the substantial role of forests as carbon
stores, as sources of carbon emissions and as carbon
sinks, has become one of the keys to understanding
and modifying the global carbon cycle.
In its Global Forest Resources Assessment 20104,
the United Nations Food and Agriculture Organization
(FAO) found that world’s forests store more carbon
than the entire atmosphere. Forests store more than
650 billion tonnes of carbon, with 44 percent in the
biomass, 11 percent in dead wood and litter, and 45
percent in the soil. In 2014, the FAO reported that
net greenhouse gas emissions from land use change
and deforestation decreased by 10 percent between
2001 and 2011 due to decreased deforestation and
increased sequestration in many countries.
Global Forest Resources Assessment 2010 (FRA 2010). Food and Agriculture
Organization of the United Nations. http://www.fao.org/forestry/fra/fra2010/en/
4
FAO. 2014. FAO Data Show Rising Agriculture Emissions, Declining Net Land-use
Change Emissions. April 11, 2014. http://climate-l.iisd.org/news/fao-data-show-risingagriculture-emissions-declining-net-land-use-change-emissions/240227/
Carbon sequestered in a typical 2,400-square-foot North American home is the
equivalent of offsetting the greenhouse gas emissions produced by driving a
passenger car over five years (about 12,500 litres of gasoline).
Solid Wood and Climate
Change
Using wood products that store carbon instead
of building materials that require large amounts of
fossil fuel energy to manufacture can help to reduce
greenhouse gases in the atmosphere. Trees grow
naturally, and the little waste generated during
processing is often used to meet the energy needs of
the mill. At the end of their first life, forest products
can be easily reused, recycled or used as a carbonneutral source of energy.
A typical 2,400-square-foot woodframe house contains 29 metric tons
of carbon, which is the equivalent
of offsetting the greenhouse gas
emissions produced by driving a
passenger car for five years (about
12,500 litres of gasoline). No other
material offers this kind of carbon
credit.
Around the world, government and
business leaders are developing
policies and procurement processes
that encourage the use of more forest
products from well-managed forests.
As part of its promotion of a carbonneutral public service, the Government
of New Zealand is requiring that
wood or wood-based products be considered as
the main structural materials for new governmentfunded buildings up to four floors. In the U.S., federal
initiatives have been announced to support innovative,
sustainable wood building materials with a goal to
protect the environment and create jobs.
Greenhouse gas emissions due to manufacturing
30,000
31% more greenhouse
gas emissions
20,000
10,000
0
Wood frame house
Concrete block house
Life cycle assessment is the appropriate tool for examining the carbon footprint of building
materials because it considers the greenhouse gas emissions associated with their production,
transportation, construction, use and eventual disposal.
•
In this graph, the embodied effects are shown for two typical, identical homes, one made
with wood and one with concrete. (Embodied effects are the environmental impacts
associated with manufacturing, transporting and constructing the houses – heating and
cooling the houses are not included);
•
It shows that the concrete-block house resulted in 31 percent more greenhouse gas
emissions than the wood-frame house.
On the cover:
The Craig Thomas Discovery and Visitor Center,
Grand Teton National Park, Wyoming
Architect: Bohlin Cywinski Jackson
The United States has over 750 million acres of forestland. More
than ninety percent of forests in the United States are naturally
reforested. Additionally, more than 1.5 million acres of forest is
replanted in the U.S. annually.
Source: FRA 2010 – Country Report, United States, Available at:
http://www.fao.org/forestry/fra/fra2010/en/
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
M O D U L E 10
Forest Practices
in the United States
Forest Practices in the United States
Forestry as a profession in North America is about 100
years old. Over the past century, the field has evolved
from practices that were focused on maximizing
timber values to approaches that are deeply rooted
in ecology, science, and principles of sustainability.
Modern day foresters complete rigorous college
programs and participate in continuing education,
certification, and licensing programs to establish and
maintain professional credentials, much the same
process as other professions such as engineering and
architecture.
Forest management in the United States operates
under layers of federal, state, and local regulations
and guidelines that foresters and harvesting
professionals must follow to protect water quality,
wildlife habitat, soil, and other resources. Laws
addressing safety and workers’ rights also govern
forestry activities. Government agencies monitor
forest management activities for compliance with
regulations.
The United States and Canada together have about
15.5 percent of the world’s total forest cover and
North America has about the same amount of forested
land now as it did 100 years ago1.
State of the World’s Forests Report, 1997 through 2009
1
A Snapshot of America’s Forests
According to the National Report on Sustainable
Forests – 2010,2 the U.S. has approximately 751
million acres of forest area, which is about one third
of the country’s total land area. “This stability is in
spite of a nearly three-fold increase in population over
the same period and is in marked contrast with many
countries where wide-scale deforestation remains a
pressing concern.”
Forty-three percent of U.S. forests are owned by
entities such as national, state and local governments;
the rest are owned by private landowners, including
more than 22 million family forest owners. The fact
that net forest growth has outpaced the amount
of wood harvested for decades supports the idea
that landowners who depend economically on the
resource have a strong incentive for their sustainable
management. This aligns with global forest data,
which indicates that forest products and industrial
roundwood demands provide the revenue and policy
incentives to support sustainable forest management.3
However, with urban development and other uses
increasingly vying for land, an issue going forward
will be making sure that landowners continue to have
reasons to keep forested lands forested.
About 30 percent of the forest area of the United
States is classified as production forest where the
production of forest products is a primary function.
About 25 percent of the forest area is designed for
the protection of soil and water and the conservation
of biodiversity, including more than 100 million acres
of reserved and roadless areas. The remaining 45
percent of the forest is used for multiple uses and is
often referred to as “working forests”.4 These lands
are cared for by public and private interests that
balance needs for income with objectives for wildlife,
water quality, recreation and aesthetics. Many of the
nation’s family forestlands reside in this category.
2
National Report on Sustainable Forests – 2010, USDA Forest Service
Ince, Peter J., Global sustainable timber supply and demand: Sustainable development in
the forest products industry, Chapter 2, Porto, Portugal : Universidade Fernando Pessoa,
2010, http://www.fpl.fs.fed.us/documnts/pdf2010/ fpl_2010_ince001.pdf
3
4
Classification based upon FAO, FRA 2010 – Country Report, United States of America
Defining Forest Sustainability
Forest sustainability was first described in the book
Sylvicultura oeconomica by German author Hans
Carl von Carlowitz, published in 1713—and, while our
understanding of what constitutes sustainability has
evolved significantly in 300 years, it has long been a
cornerstone of forest management. Von Carlowitz’s
work planted the seed for what we now know as
sustainable development, defined in the landmark
1987 report of the World Commission on Environment
and Development (the ‘Brundtland Report’) as
“development that meets the needs of the present
without compromising the ability of future generations
to meet their own needs.”
The United Nations Food and Agriculture Organization
(UNFAO ) defines sustainable forest management as
“the stewardship and use of forests and forest lands
in a way, and at a rate, that maintains their biological
diversity, productivity, regeneration capacity, vitality
and their potential to fulfill, now and in the future,
relevant ecological economic and social functions,
at local, national and global levels, and that does not
cause damage on other ecosystems.”
In the U.S. and Canada, forest sustainability is
measured against criteria and indicators that represent
the full range of forest values, including biodiversity,
ecosystem condition and productivity, soil and
water, global ecological cycles, economic and social
benefits, and social responsibility. Sustainability
criteria and indicators form the basis of individual
country regulations as well as third-party sustainable
forest certification programs
Managing Diverse Forests
Forest management is often described as a blending
of art and science. Foresters must follow all laws
and regulations, and apply forestry science. This
includes all best management practices, and applying
the results of ongoing research. Foresters must also
nurture the art of recognizing the unique features of a
specific forest and site, and develop the management
design that will meet diverse environmental,
economic and social interests, including the needs
and objectives of the owner. The blending of art
and science that occurs in forest management is
similar to what occurs in a building project. Like the
multi-disciplinary team that designs and constructs
buildings, sustainable forest management involves
a team that includes foresters, engineers, biologists,
hydrologists, surveyors and loggers that plan and care
for the forest. In both
cases, members of the team must address the
technical requirements and obligations of their
profession while taking into consideration the tastes
and desires of the project partners and owners.
In the case of forestry, this includes caring for the
forest while meeting the needs of landowners,
the environment, and their community.
The use of responsible forest management
in the United States has resulted in more than
75 consecutive years of net forest growth that
exceeds annual forest removals. This track record
of annually growing more wood than is harvested has
continued despite increasing demands and growing
populations. It is a testament to leadership in forestry
practices and sustainability.
Growing New Forests
Today’s forestry involves many different management
tools and techniques. A common approach is the
use of ecosystem-based management, which is
an integrated, science-based approach to the
management of natural resources. This approach
aims to sustain the health, resilience and diversity of
ecosystems while allowing for sustainable use of the
goods and services they provide.
Through the use of diverse silviculture practices,
foresters tend to the forest, ensuring regeneration,
growth and forest health, and providing benefits that
support a full range of forest values. For example,
forest management practices are often selected to
mimic natural disturbances and the cycles of nature
that are associated with a specific region, forest
type or species. Natural disturbances, including
windstorms, hurricanes, ice storms, forest fires and
insect or disease outbreaks, are a fact of life in the
forest. To mimic these events, foresters may vary the
size of the openings created by forest management,
the intensity of management, the retention of
wildlife reserve areas, and the frequency with which
management occurs.
A silviculture system covers all management activities
related to growing forests – from early planning
through harvesting, replanting and tending the new
forest. Forest managers consider a wide variety of
factors when choosing a silviculture system, including
tree species, their age, condition, soils, ecology, and
considering other values such as wildlife habitat,
water quality and scenery.
Conserving Forest Values
Biological diversity, or biodiversity, refers to the
variety of species and ecosystems on earth and their
ecological systems. An important indicator of forest
sustainability, it enables organisms and ecosystems
to respond to and adapt to environmental change.
Conserving biodiversity is an essential part of forest
sustainability and involves strategies at different
scales. At the landscape level, networks of parks and
protected areas conserve a range of biologically and
ecologically diverse ecosystems. Tens of millions
of acres of forests are protected within wilderness
areas and parks and through regional and local
programs. Forests are also protected by established
conservation easements developed through the work
of local land trusts.5
5
Federal Sustainability Report 2010
The diverse forests of the United States are managed
with one or a blend of a few primary silviculture
systems:
• The clearcut system leaves some healthy trees
within the cut and a perimeter of undisturbed
forest to regenerate the tract, protect soil and
water resources, and eliminate non-native tree
species competition.
• The shelterwood system harvests trees in
stages over a short period of time so the new
forest grows under the shelter of the existing
trees.
• The selection system removes timber as single
trees or in small groups at relatively short
intervals, repeated indefinitely. This is done
carefully to protect the quality and value of the
forest area.
Clearcutting is used when the young trees of a
species need an abundance of sunlight to germinate
and to compete successfully with grasses and other
plants. It is usually used to grow tree species that
historically found open sunlight by following large
natural disturbances such as windstorms or wildfire. It
provides the direct sunlight needed to effectively grow
some native species, while helping to create a mix of
forest ages across the landscape, including the young
forests preferred by certain wildlife.
Up until the early 20th century, settlers coming to
the United States cleared an average of 2.1 acres
of forest per person to survive and grow food.6
The establishment of industrial agriculture and other
changes in land use have mitigated the need for forest
clearing since that time, and forest acreage in the
United States has been stable for over a century.
The U.S. reported an annual increase in forest area
of 0.12 percent in the 1990s and 0.05 percent from
2000 to 2005.7
Outside of North America, however, the conversion
of forestlands to non-forest uses continues at a
significant rate, predominantly in developing tropical
countries. Deforestation is the permanent conversion
of forest land to non-forest uses, and globally it
accounts for 17 percent of the world’s greenhouse
gas emissions. More than two-thirds of global forest
loss is still attributed to clearing for agriculture.
American Forests: A History of Resiliency and Recovery by Douglas W. McCleary. 1997.
Forest History Society, Issues Papers Series, Durham, NC 58 pp.
6
The State of America’s Forests, M. Alvarez, 2007, Society of American Foresters; State of
the World’s Forests Report, 2007
7
Third-party Forest
Certification
While forestry is practiced in keeping with regulations
and guidelines that consider environmental, economic
and social values for that particular country, voluntary
forest certification allows forest companies to
demonstrate the effectiveness of their practices
by having them independently assessed against
sustainability standards.
Wood is the only building material that has third-party
certification programs in place to demonstrate that
products being sold have come from a sustainably
managed resource. North America has more certified
forests than any other jurisdiction.
As of August 2013, more than 500 million acres of
forest in the U.S. and Canada were certified under
one of the four internationally recognized programs
used in North America: the Forest Stewardship
Council (FSC), Sustainable Forestry Initiative (SFI),
Canadian Standards Association’s Sustainable Forest
Management Standards (CSA), and American Tree
Farm System (ATFS). This represents more than half
of the world’s certified forests.
According to the National Association of State
Foresters, “credible forest certification programs
include the following fundamental elements:
independent governance, multi-stakeholder standard,
independent certification, complaints/appeals
process, open participation and transparency. [...]
While in different manners, the ATFS, FSC, and
SFI systems include the fundamental elements of
credibility and make positive contributions to forest
sustainability.”8 Similarly, the World Business Council
on Sustainable Development released a statement
supporting an inclusive approach that recognizes
these programs as well as CSA (and others).
The FSC, SFI, CSA and ATFS programs all depend
on third-party audits where independent auditors
measure the planning, procedures, systems and
performance of on-the-ground forest operations
against the predetermined standard. The audits,
performed by experienced, independent foresters,
biologists, socio-economists or other professionals,
are conducted by certification bodies accredited to
award certificates under each of the programs. A
certificate is issued if a forest operation is found to be
in conformance with the specified forest certification
standard.9
Forest Certification as it Contributes to Sustainable Forestry, National Association of
State Foresters, 2013, NASF- 2013-2, www.stateforesters.org
8
http://www.naturallywood.com/sites/default/files/Third-Party-Certification.pdf; http://
www.sfiprogram.org/sfistandard/american-tree-farm-system/
9
SFI-01569
photographer: Candace Kenyon
Sources:
FAO. 2010. Country Report: United States. http://www.fao.org/
forestry/fra/fra2010/en/
Society of American Foresters. 2007. The State of America’s
Forests. http://www.safnet.org/publications/americanforests/
StateOfAmericasForests.pdf
Green buildings
Future of America’s Forests and Rangelands – Forest Service
2010 Resources Planning Act Assessment. USDA – Forest
Service. Gen. Tech. Rep. WO-87. August 2012. Available online
at: http://www.treesearch.fs.fed.us/pubs/41976/ To download
the pdf: http://www.fs.fed.us/research/publications/gtr/gtr_
wo87.pdf
• Use less energy and water
WoodWorks. 2011. Sustainable Forestry in North America:
A Primer for Design and Building Professionals.
• Mitigate climate change
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
M O D U L E 11
Green
Building Tools
Finding the Right Tools
While the increased interest in sustainable building design has encouraged research into
building products and performance, it continues to be a challenge to measure the overall
impact of buildings on the environment over the course of their service lives – and advice is
often contradictory.
Product directories, rating systems and other tools are available to support design
and construction decisions. However, these must be evaluated carefully to ensure
they meet the specific needs of each application, and to identify any limitations.
For example, some green building rating systems may be too narrowly
focused, ignoring the importance of far-reaching strategic decisions, while
rewarding less important ones disproportionately.
Green building tools include:
• product labelling by third-party certifiers such as independent forest certification programs
• rating systems that evaluate products/designs such
as LEED (Leadership in Energy and Environmental
Design), Green Globes and the National Association
of Home Builders (NAHB) National Green Building
Standard
• practice guidelines such as green home
building guidelines
• software such as the ATHENA Institute’s
EcoCalculator
• procurement policies such as the
U.S. Environmental Protection
Agency’s environmentally
preferable purchasing
• Environmental Product
Declarations (EPDs)
• green building codes such
as CalGreen and the model
code International green
Construction Code (IgCC).
Green design requires smart
tools to decipher all the
conflicting information, lack
of clarity on definitions,
and a constantly changing
landscape as the field
evolves and expands.
green
product
ratings
integrated
design
process
computer
modelling
& design
green building
rating systems
case studies
Green Design
Tools
technical
research
life cycle
assessment
software
peer
consultation/
review
Product Labelling and Certification
As demand grows for products and designs that
represent a sound environment choice, more
companies are labeling their products as “green.”
TerraChoice Environmental Marketing (UL
Environment) has produced a report called the Seven
Sins of Greenwashing (www.sinsofgreenwashing.org)
that offers criteria to help consumers judge whether
a product or program is environmentally beneficial.
It includes a list of some of North America’s most
credible eco-labels – including third-party forest
certification labels, cleaning products and organic
certification.
Green Building Rating
and Assessment
Environmental rating systems can help building
industry professionals evaluate and differentiate
their product or design. The standards set by rating
systems generally exceed those required by building
codes.
The best systems measure performance rather than
prescribe solutions, and are based on life cycle
assessment. They offer a credible, consistent basis
for comparison, evaluate relevant technical aspects of
sustainable design, and should not be too complex or
expensive to implement or confusing to communicate.
Most developed countries have adopted one or
more green building rating systems, beginning with
the United Kingdom, which introduced the BREEAM
(Building Research Establishment Environmental
Assessment Method) in 1990. In North America, green
rating systems include LEED, Green Globes and the
NAHB National Green Building Standard. A choice
in rating systems helps to strengthen green design,
with processes to meet the diversity of building
needs, sizes and budgets. It also encourages market
competition, ensuring continuous improvement.
The LEED green building rating system, developed by
the U.S. Green Building
Council, addresses
specific building-related
environmental impacts
using a whole building
environmental performance
approach. In addition
to LEED-NC (for new
construction and major
renovations), there are versions for existing buildings,
commercial interiors, core and shell, homes, and
TerraChoice President and CEO Scott McDougall
says a 2009 survey of 2,219 consumer products
showed that 98 percent of companies committed at
least one Sin of Greenwashing, and some marketers
are creating fake labels or false suggestions of thirdparty endorsement. “Despite the number of legitimate
eco-labels out there, consumers will still have to
remain vigilant in their green purchasing decisions,”
he says.
Wood is one of the few building products backed by
well-established third-party certification programs,
and North America has more certified lands than any
other region of the world.
neighbourhood development. In 2013, the US Green
Building Council (USGBC) released the latest version
of the LEED green building rating system (LEED v4).
(For information in the United States: www.usgbc.org/
LEED/. For information in Canada: www.cagbc.org)
Green Globes, is a web-based environmental
assessment and certification system that bills itself
as offering an effective,
practical and affordable
way to assess and improve
the sustainability of new
and existing buildings.
In the U.S., it is offered
exclusively by the Green
Building Initiative (GBI)
who initiated the first ANSI standard for commercial
green building. In Canada, the federal government
uses the Green Globes suite of tools and it is the basis
for the Building Owners and Managers Association
of Canada’s (BOMA) “Go Green Plus” program. (For
information in the United States: www.thegbi.org. For
information in Canada: www.greenglobes.com)
The NAHB National Green Building Standard
is the first green building rating system to be
approved by the ANSI.
Building on the Model
Green Home Building
Guidelines developed
by the NAHB Research
Centre, it provides a
common benchmark for
recognizing and rewarding
green residential design,
development, and construction practices in the United
States. Known as ANSI/ICC 700-2008, the National
Green Building Standard is a joint effort between
the International Code Council and NAHB. (More
information is available at www.nahbgreen.org)
Environmental Data Sources:
Life Cycle Assessment
Software
Life cycle assessment software allows a designer to
capture and account for the breadth of environmental
and economic considerations in one application.
The Building for Environmental and Economic
Sustainability (BEES) software program was
created by the U.S. National Institute of Standards
and Technology. BEES has 10 impact categories:
acid rain, ecological toxicity, eutrophication, global
warming, human toxicity, indoor air quality, ozone
depletion, resource depletion, smog and solid waste.
(For more information: www.wbdg.org/tools/bees.php)
The ATHENA Institute is a non-profit organization
that provides life cycle assessment services and tools
to support green building. Its Impact Estimator for
Buildings is a full-capability tool that allows designers
to evaluate the environmental impact of each decision
as they go through the process of putting a building
together conceptually. Its EcoCalculator is a simplified
tool, where hundreds of common building assemblies
have been pre-calculated, requiring minimal input
from the designer. (For more information: http://www.
athenasmi.org/tools/impactEstimator/)
government agencies of several European countries.
Now, the EPD concept is moving rapidly into the
mainstream. The American Wood Council (AWC)
and Canadian Wood Council (CWC) have released
EPDs for North American wood products, including
softwood lumber, plywood, oriented strand board,
and glue-laminated lumber.
Procurement Policies
Globally, governments are introducing policies to
increase the use of wood in an attempt to reduce
greenhouse gas emissions and support their
sustainability programs. Examples include:
•
Changes in national building regulations in many
European countries to encourage multi-story
wood buildings – in the United Kingdom, a ninestory apartment building that includes eight
stories of wood over one-story of concrete is
considered the first modern tall timber residential
building. The world’s tallest wood building is
currently the 10-story Forte Building completed in
2012 in Melbourne, Australia. Additional projects
have been proposed, including a potential 34story building in Stockholm, Sweden and
a 20-story tower in Vancouver, Canada.
A 30-story wood building has been approved
for construction in Sweden.
•
In Canada, the governments of British Columbia
and Quebec have policies that encourage the use
of wood in public buildings.
Environmental Product Declarations
An Environmental Product Declaration, or EPD, is a
standardized report of environmental impacts linked
to a product or service. An EPD is based on life cycle
assessment, which provides a basis for comparing
environmental performance and substantiating
marketing claims. Until recently, EPD development
was limited to organizations associated with the ISO
14000 series of standards within the International
Organization for Standardization (ISO) and the
A mixed-use project, Avalon Anaheim Stadium includes 251 luxury
apartment units and 13,000 square feet of retail and restaurant
space over a 210,000-square-foot podium deck with two levels of
subterranean parking. It is located in the heart of Anaheim’s Platinum
Triangle district. “Podium” buildings, which include multiple stories
of wood over an elevated concrete “podium deck,” have become
especially prevalent. With ever increasing land costs and the rising
cost of steel and concrete, developers are turning to wood designs
that offer greater density and a higher percentage of rentable square
footage than traditional garden-style apartments while also being
cost effective—both in terms of material and labor. Wood’s other
benefits, such as speed of construction, design flexibility, and reduced
environmental impact, add to the value proposition.
Avalon Anaheim Stadium Apartments, Anaheim CA
Architect: Withee Malcolm Architects
Photos by Michael Arden - Arden Photography
Organizations and
Networks
The U.S. Green Building Council (USGBC) and the
Canadian Green Building Council are non-profit
organizations that aim to transform the way buildings
and communities are designed, built and operated,
enabling an environmentally and socially responsible,
healthy, and prosperous environment that improves
the quality of life. USGBC has developed the LEED
rating system. For more information:
www.usgbc.org (United States)
www.cagbc.org (Canada)
www.worldgbc.org (international)
The National Association of Home Builders (NAHB)
is a trade association for the housing and building
industry in the United States. NAHB is a federation
of more than 800 state and local associations.
Its affiliates include the HIRL: Home Innovation
Research Laboratory.
For more information: www.nahb.org
The Green Building Initiative is a not-for-profit
education and marketing initiative dedicated to
accelerating the adoption of building practices that
result in energy-efficient, healthier and environmentally
sustainable buildings by promoting credible and
practical green building approaches for residential
and commercial construction. For more information:
www.thegbi.org
The American Institute of Architects (AIA) serves
as the voice of the architecture profession and the
resource for their members in service to society.
They carry out advocacy, information, and community
outreach. Each year the AIA sponsors hundreds of
continuing education experiences to help architects
maintain their licensure, provides web-based
resources, conducts market research and provides
analysis of the economic factors that affect the
business of architecture. For more information:
www.aia.org
James and Anne Robinson Nature Center, Columbia, MD
Architect: GWWO, Inc / Architects
Photo: Robert Creamer Photography
The 23,000-square-foot James and Anne Robinson Nature Center reflects years of creative and innovative efforts of educators, community leaders,
designers, wildlife experts, historians, and resource conservationists. Designed by GWWO Architects, the building demonstrates the latest in
sustainable design ideas, craftsmanship, and materials, including geothermal heating, green roofing, and even recycled wood from the Robinsons’
own barn. The Center has been recognized by Associated General Contractors as the “Best Sustainability Project of the Year in New Construction”
and was recently awarded Platinum LEED (Leadership in Energy Design) Certification, the highest rating from the U.S. Green Building Council.
Other Resources
Energy Star
(www.energystar.gov) is an international standard for energyefficient consumer products. First created as a U.S. government
program in 1992, it operates in Canada, Europe, Japan and
Australia. Energy Star rates energy-related value for products
in more than 35 categories, including HVAC systems, lighting
fixtures, office equipment, roofing products, windows, doors
and skylights.
The U.S. Environmental Protection Agency’s
Environmentally Preferable Purchasing
(www.epa.gov/opptintr/epp) rates building materials and
products based on pollution prevention, life cycle analysis,
comparison of environmental impacts, environmental
performance, and environment/price performance ratio. Product
categories include: paints, plumbing, HVAC, lighting, gypsum
board, carpets, concrete, coatings, sealants, flooring, doors,
and windows.
On the cover:
Campus Services Building,
Western Washington University, Bellingham
Zervas Group Architects
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Building
Greenwith
Wood
M O D U L E 12
Links to Information
Sources
Building
Greenwith
Wood
M O D U L E 13
Forest Carbon
Forests - Natural Carbon, Natural Energy
and Carbon Storage
Forests play a critical role in filtering and renewing
our air. Trees absorb carbon dioxide (CO2) and water
(H2O), and release oxygen (O2). The carbon absorbed
is stored until the trees die and decay or are burned in
a wildfire, at which point the carbon is released back
into the atmosphere. Some of the carbon absorbed
by trees is stored for a long period of time within the
forest.
Less known is the fact that trees use carbon (C) to
produce wood, and that products made from wood
continue to store carbon for as long as they exist. In
fact, one-half the weight of wood is carbon.
There is growing awareness among building designers
that using wood can reduce a building’s carbon
footprint, provided it comes from a sustainably
managed forest. At the core of wood’s carbon benefit
is the fact that as trees grow they absorb CO2 from
the atmosphere and incorporate the carbon into their
wood, leaves or needles, roots and surrounding soil.
Over time, one of three things happens:
• When the trees get older, they start to decay and
slowly release the stored carbon.
• The forest succumbs to wildfire, insects or disease
and releases the carbon quickly.
• The trees are harvested and manufactured into
products, which continue to store much of the
carbon. In the case of wood buildings, the carbon
is kept out of the atmosphere for the lifetime of the
structure—or longer if the wood is reclaimed at the
end of the building’s service life and either re-used
or remanufactured into other products.
The unique benefits of wood result from how it is
made – within forests using solar energy. Solar energy
drives the process of photosynthesis and wood
formation. Transformation of wood into useful building
materials takes relatively little additional energy.
Carbon Cycle: Sustainable Forest
Management and Wood Products
*Estimated by the
Wood Carbon
Calculator for
Buildings
(WoodWorks US
-http://woodworks.
org), based on
research by Sathre,
R. and J. O’Connor,
2010. A Synthesis
of Research on
Wood Products and
Greenhouse Gas
Impacts,
FPInnovations.
Note: C02 on this
chart refers to C02
equivalent. Figures
calculated May
2016.
**US Environmental
Protection Agency
Equivalencies
Calculator.
Unless the forest area is converted to another use, such as urban development, agriculture or mining, the cycle begins again as
the forest regenerates and young seedlings once again begin absorbing CO2. The market for wood encourages landowners to
keep land under forest, helping to avoid large-scale losses of carbon to the atmosphere via land use change.
“IPPC (Intergovernmental Panel on Climate Change) has stated that ‘In the
long term, a sustainable forest management strategy aimed at maintaining or
increasing forest carbon stocks, while producing an annual sustained yield
of timber, fibre or energy from the forest, will generate the largest sustained
mitigation benefit.’ The analysis contained in the present report gives strong
support to IPCC’s assertion that sustainable management of production forests
represents an important mitigation option over the long term.”2
Impact of the global forest industry on atmospheric greenhouse gases, 2010, UNFAO. http://www.fao.org/docrep/012/i1580e/
i1580e00.htm
2
Photo courtesy of Plum Creek
Forests - Natural Ecosystems, Wildlife Habitat,
Renewable Products and Carbon Storage
Unlike mines and farms, forests are diverse
ecosystems. As a result they provide many amenities.
Forests provide a wide variety of habitats for wildlife
species – from mammals and birds to reptiles and
amphibians – and influence marine and fish habitats.
They filter water for communities and local businesses.
They offer areas for recreation, relaxation and
enjoyment of nature – places for quality time with
friends and families. And, they provide food, fiber and
building products that support our quality of life.
Wood is also renewable. As long as forests are
managed sustainably, trees can be grown, harvested,
replenished, and then harvested again and again in an
ongoing cycle of harvest, renewal, and growth.
A great deal of research has been undertaken to
determine how forests can be managed to maximize
their carbon benefits. According to a new report from
the Society of American Foresters1, numerous studies
of forest carbon relationships show that a policy of
active and responsible forest management is more
effective in capturing and storing atmospheric carbon
than a policy of hands-off management that precludes
periodic harvests and use of wood products.
While acknowledging that it is not appropriate to
manage every forested acre with a sole focus on
carbon mitigation, the report’s authors conclude
(among other things), that:
• Wood products used in place of more energyintensive materials, such as metals, concrete and
plastic reduce carbon emissions, store carbon,
and can provide additional biomass that can be
substituted for fossil fuels to produce energy.
• Sustainably managed forests can provide greater
carbon mitigation benefits than unmanaged forests,
while delivering a wide range of environmental
and social benefits including timber and biomass
resources, jobs and economic opportunities, clean
water, wildlife habitat, and recreation.
As with all aspects of forestry, choosing not to manage
also has consequences, and this also impacts forest
lands carbon. Young, healthy forests are carbon sinks
because they’re actively absorbing carbon dioxide as
they grow. As forests mature, they generally become
carbon cycle-neutral because primary productivity
declines. Many continue to store substantial amounts
of carbon indefinitely— old growth forests in the U.S.
and Canada represent significant carbon sinks—but
the probability of massive carbon loss also increases.
Where forests are killed by large-scale natural
disturbances (such as wildfires and insect or disease
infestations), they emit their stored carbon without
providing the benefits available through product and
energy substitution.
According to the Food and Agriculture Organization
of the United Nations, “Several aspects of the forest
industry’s activities are not adequately captured
by looking at only the emissions and sequestration
accomplished in the value chain. For example, the use
of wood-based building materials avoids emissions
of 483 million tonnes of CO2 equivalent a year, via
substitution effects. In addition, by displacing fossil
fuels, the burning of used products at the end of the
life cycle avoids the emission of more than 25 million
tonnes of CO2 equivalent per year, which could be
increased to 135 million tonnes per year by diverting
material from landfills.
“Wood products are manufactured from renewable
raw material; they are reusable and biodegradable,
and they continue to store carbon throughout their
lifetime. These characteristics make wood an excellent
alternative to many of the materials that are now widely
used in construction and consumer goods, which
leave a much larger ‘carbon footprint’ and include
concrete, steel, aluminum and plastic. Increasing
production and consumption of wood products will
therefore be part of a sustainable future.”2
Managing Forests because Carbon Matters: Integrating Energy, Products, and Land
Management Policy, Journal of Forestry, 2011, American Society of Foresters.
www.safnet.org/documents/JOFSupplement.pdf
1
2
State of the World’s Forests – 2012 United Nations Food and Agriculture Organization
More than ninety percent of forests in the United States are
naturally reforested. Additionally, more than 1.5 million acres
of forest is replanted in the U.S. annually.
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
Managing Forest Carbon
• Reduce waste
• Are healthy for people
The United States has over 750 million acres of forestland. Forests
cover about one-third of the nation, and the total forest area in the
United States has been stable for about 100 years.3
and the planet
When a tree is cut down, 40 to 60 percent of the carbon stays in
the forest, and the rest is removed in the logs, which are converted
into forest products.4 Some carbon is released when the forest soil
is disturbed during harvesting, and the roots, branches and leaves
left behind release carbon as they decompose.
The amount of carbon dioxide released through harvesting is small
compared to what is typically experienced through forest fires and
other natural disturbances, such as insect infestations and disease.
Trends in US Forestland Area 1630-2012
1200
1000
On the cover:
Oregon Coos Bay
Photo courtesy of Plum Creek
Million Acres
800
600
400
200
0
1630
1907
1920
1938
1953
1970
1630
1977
1987
1992
1997
2009
2012
Source: USDA - Forest Service, 2013
3
National Report on Sustainable Forests - 2010, USDA Forest Service
Does harvesting in Canada’s forests contribute to climate change? Canadian Forest Service, 2007,
www.sfmcanada.org/images/Publications/EN/CFS_DoesHarvestingContributeToClimateChange_EN.pdf
4
© 2015
Key Websites
American Forest Foundation
www.forestfoundation.org
American Forest & Paper Association
www.afandpa.org
American Wood Council
www.awc.org
National Alliance of Forest Owners
www.nafoalliance.org
USDA Forest Service – Research and
Development
http://www.fs.fed.us/research/
AFF works nationwide and in partnership with local,
state, and national groups to address ecological and
economic challenges that require the engagement of
family forest owners.
The American Forest & Paper Association (AF&PA)
serves to advance a sustainable U.S. pulp, paper,
packaging, and wood products manufacturing industry
through fact-based public policy and marketplace
advocacy. AF&PA member companies make products
essential for everyday life from renewable and
recyclable resources and are committed to continuous
improvement through the industry’s sustainability
initiative - Better Practices, Better Planet 2020.
The American Wood Council (AWC) is the voice of North
American traditional and engineered wood products,
representing over 75 percent of the industry. AWC’s
engineers, technologists, scientists, and building code
experts develop state-of-the-art engineering data,
technology, and standards on structural wood products
for use by design professionals, building officials, and
wood products manufacturers to assure the safe and
efficient design and use of wood structural components.
AWC also provides technical, legal, and economic
information on wood design, green building, and
manufacturing environmental regulations advocating
for balanced government policies that sustain the wood
products industry.
NAFO is an organization of private forest owners
committed to advancing national policies that promote
the economic and environmental benefits of privatelyowned forests. NAFO membership encompasses more
than 80 million acres of private forestland in 47 states.
Working forests in the U.S. support 2.4 million jobs.
The research and development (R&D) arm of the
Forest Service, a component of the U.S. Department
of Agriculture, works at the forefront of science to
improve the health and use of our Nation’s forests
and grasslands. Research has been part of the Forest
Service mission since the agency’s inception in 1905.
Key Websites
U.S. Global Change Research Program
http://www.globalchange.gov
U.S. WoodWorks
www.woodworks.org
reThink Wood
www.rethinkwood.com
The U.S. Global Change Research Program (USGCRP)
is a Federal program that coordinates and integrates
global change research across 13 government agencies
to ensure that it most effectively and efficiently serves
the Nation and the world. USGCRP was mandated
by Congress in the Global Change Research Act of
1990, and has since made the world’s largest scientific
investment in the areas of climate science and global
change research.
WoodWorks is an initiative of the Wood Products
Council, which is a cooperative venture of major North
American wood associations, research organizations
and government agencies. Established to provide
architectural and engineering support related to
nonresidential and multi-family wood buildings in
the U.S., WoodWorks offers a wide range of free
resources—including one-on-one project support,
online training, web-based tools (e.g., cost and other
calculators, CAD/REVIT details, span tables), and
educational events such as Wood Solutions Fairs and
technical workshops.
Formed in 2011, the reThink Wood initiative aims
to project a unified front and present a common
message as it relates to wood performance, cost and
sustainability, making it easier for the industry to speak
with a cohesive voice and educate about the advantages
of using wood in building.
reThink Wood is not an organization; it has no staff.
Representatives from funders and partner associations
such as the Binational Softwood Lumber Council,
Forestry Innovation Investment and the Softwood
Lumber Board work with key delivery agents such as
WoodWorks, American Wood Council and the Canadian
Wood Council.
Green Building Rating Systems
BREEAM (United Kingdom)
www.breeam.org
Green Globes
United States (Green Building
Initiative)
www.thegbi.org
LEED
(Leadership in Energy and
Environmental Design)
www.usgbc.org/LEED
U.S. Green Building Council
National Association of Home
Builders
NAHB National Green Building
Program
ANSI ICC 700-2008 National Green
Building Standard™
www.nahbgreen.org
www.nahbgreen.org/Certification/ngbs.
aspx/
Third-party Forest Certification
Programs Used in the United States
American Tree Farm System
www.treefarmsystem.org
Programme for the Endorsement
of Forest Certification
www.pefc.org
Forest Stewardship Council
www.us.fsc.org
www.ic.fsc.org
Sustainable Forestry Initiative
www.sfiprogram.org
On the cover:
Marselle Condominium
Seattle, WA
PB Architects
Matt Todd Photography
Green buildings
• Mitigate climate change
• Use less energy and water
• Use fewer materials
• Reduce waste
• Are healthier for people
and the planet
Wood Specification:
Life Cycle Assessment
Terminology
Typical environmental impacts of
interest:
Material usage: amount of material
used, expressed in terms of mass
and/or volume.
Embodied energy: amount of
energy associated with extracting,
processing, manufacturing,
transporting, and assembly
of building materials.
Global Warming Potential (GWP):
a measure of how much
a given mass of greenhouse gas is
estimated to contribute to global
warming. It is a relative scale which
compares the gas in question to the
same mass of carbon dioxide (the
GWP of which is by convention equal
to 1). A GWP is calculated over
a specific time interval which must
be stated whenever a GWP is quoted.
Air pollution: sulphur dioxide, nitrous
oxides, methane, particulates, and
volatile organic compounds.
Solid waste generation: solid waste
generated during manufacturing
and construction.
Water consumption: quantity of
water use associated with a material
process.
Water pollution: the effluent
deposited into water bodies.
The best way to determine the full environmental impacts of a building
product or design is through life cycle assessment (LCA). LCA analyzes the total
environmental impacts of all materials and energy flows, either as input or
output, over the life of a product from raw material to end-of-life disposal or
to rebirth as a new product. For buildings and building products this includes
resource extraction, manufacturing, on-site construction, occupancy, and
eventual demolition and disposal or reuse. LCA-based Environmental Product
Declarations (EPDs) also provide information about environmental impacts
during the manufacture and life of a product. All of the major green building
rating systems and model codes in North America recognize and encourage use
of LCA and/or EPDs in building design and materials selection.
Why Life Cycle Assessment Adds Value
• Sustainable design is complex and integrated.
One way to understand the complex interaction of
factors involved in new construction, renovation,
and retrofits is through life cycle assessment. LCA
provides information about ongoing environmental
impacts of building operation as well as upstream
environmental burdens of the building materials and
products.
• Life cycle assessment provides measurable outputs
that can help clients make meaningful decisions that
not only affect their real estate portfolio but also
inform their climate change mitigation strategies and
their corporate marketing and recruitment efforts.
• Commercial building clients are looking more closely
at the environmental impacts of their operations
and investments. Spurred by regulation and market
forces, many corporations are committing to
reporting their quality assurance and environmental
initiatives and to tracking their improvements.
• Application of LCA to building design and use of LCA
and/or EPDs in materials selection can gain credits in
pursuit of green building certification.
An Environmental Product Declaration (EPD)
is a standardized report of environmental
impacts linked to a product or service.
More explicitly, an EPD is a standardized,
third-party verified, and LCA-based label
that communicates the environmental
performance of a product and that is
applicable worldwide.
An EPD includes information about both
product attributes and production impacts
and provides consistent and comparable
information to industrial customers and
end-use consumers regarding environmental
impacts. The nature of EPDs also allows
summation of environmental impacts along
a product’s supply chain – a powerful
feature that greatly enhances the utility of
LCA-based information
• The life cycle assessment process is defined under ISO 14040/14044 (Environmental Management—
Life Cycle Assessment—Principles and Framework / Environmental Management—Life Cycle
Assessment—Requirements and Guidelines) which is part of the internationally recognized series of
standards that address environmental management and is familiar to most businesses.
Incorporating life cycle assessment positions a business as an industry leader and provides it with a
competitive advantage, particularly in markets where LCA is recognized. Taking a proactive position also
reduces costs associated with future regulatory compliance.
Resource
Extraction
Manufacturing
On-site
Construction
Occupancy /
Maintenance
Life Cycle of Building Products
GREEN BUILDING RATING SYSTEM GUIDES
Demolition
Recycling /
Reuse / Disposal
Wood Specification: Life Cycle Assessment
Wood: A Carbon-neutral
Building Material
• Manufacturing of wood products requires
less total energy, and in particular less
non-renewable (fossil) energy, than the
manufacturing of most alternative materials.
• The drying process accounts for most of the
energy used in the manufacture of wood
products. Wood processing residues (such as
sawdust) are commonly used to fuel the drying,
avoiding depletion of fossil fuels.
• When sustainable forestry is practiced, trees,
and the carbon they contain, are replenished
as they are harvested. Carbon is obtained from
atmospheric CO2 via photosynthesis, becoming
part of wood as a tree grows in height and
diameter.
for as long as they are in use. The capacity
of trees to absorb and store carbon can be
factored against the carbon emissions incurred
during drying, processing, and transporting
wood products. The result is a very low carbon
building material.
• Timber-based building products continue to store
carbon absorbed during the tree’s growing cycle
How to Include Life Cycle Assessment in Design
Early green building rating initiatives in North
America were all built upon lists of specific prescribed
measures for reducing energy consumption and
various environmental impacts. Such measures
remain in place today within many green building
rating systems. Arranged within categories such
as Energy, Water, Indoor Air Quality, Materials
and Resources, and Site, prescriptive lists of
recommended or required measures for addressing
specific concerns outline the path toward
environmentally better buildings. Each measure
typically addresses a single concern or attribute such
as recycled, recycled content, rapidly renewable, and
local. Recommendations for improving environmental
performance of buildings and construction practices
have long varied among the various rating initiatives.
Within this context, recommendations for use of
wood and wood products varied as well.
Most of the 42 green building programs in use in
North America today continue to rely on prescriptive
provisions. However, a shift away from prescriptive
measures and toward performance and systematic
assessment has begun that is reflected in Green
Globes, LEED and several other rating systems, as
well as in CalGreen, and in the IgCC and ASHRAE
189.1 model codes.
Credit can be achieved (and invaluable information
about building design can be gained) through use
of life cycle assessment of at least two alternative
designs or of successive iterations in the design
process. Use of EPDs to inform building product
choices also provides essential information while
also gaining credits within leading green building
programs.
The move away from a prescriptive basis and toward
a performance basis involves emphasis on reliance
on systematic, life cycle assessment-based tools and
sources of information. It is a major step forward,
and a change that allows simultaneous, systematic,
science-based consideration of multiple attributes
rather than adherence to intuition-based single
attributes.
Applicable worldwide, EPDs are a standardized (ISO
14025) tool for communicating the environmental
performance of a product or system. Europe, Asia and
Australia have been the most advanced economies to
use environmental product declarations.
Next Steps: Where Proficiency in
Life Cycle Assessment can Lead
Life cycle assessment (LCA) is sometimes described as mysterious and extremely complicated.
Yet, what is involved is simply a thorough accounting of resource consumption, including energy,
and emissions and wastes associated with production and use of a product. For a “product” as
complex as a building this means tracking and adding up inputs and outputs for all assemblies
and subassemblies – every framing member, panel, fastener, finish material, coating, and so on.
Further, to ensure that results and data developed by different LCA practitioners and in different
countries are comparable (i.e. that results allow apples to apples comparisons) LCA practitioners
must strictly adhere to a set of international guidelines as set forth by the International Organization
for Standardization (ISO). Tracking products and co-products through a supply chain and properly
allocating resource use, emissions and wastes to various outputs can indeed be a complicated
and expensive procedure for those who conduct assessments. However, for users of LCA tools,
information has never been easier to access. User-friendly, low-cost (in most cases free) LCA tools
allow building designers to rapidly obtain life cycle impact information for an extensive range of
generic building assemblies, or with a bit more work and modest investment to develop full building
life cycle analyses on their own. LCA-based data is now also available in the form of easy-tounderstand, standard format environmental product declarations (EPDs) for a wide range
of products.
GREEN BUILDING RATING SYSTEM GUIDES
Life Cycle Assessment Tools
LCA software offers building professionals powerful
tools for comparing products and calculating the
lifetime impacts of building products or assemblies.
Data gathered via LCA are of particular interest to
long-term building investors who are concerned
about the overall impacts of their buildings and
about protecting the value of their assets.
A summary of tools is available on the website of
the United States Environmental Protection Agency
(http://www.epa.gov/nrmrl/lcaccess/resources.html).
The most popular are listed below.
For General Building Professionals
EPDs and Forest Certification
The wood industry has been a leader in the development of Environmental Product Declarations (EPDs). An
EPD is a standardized, third-party verified label that communicates the environmental performance of a
product, is based on lCA, and is applicable worldwide.
An EPD includes information about both product attributes and production impacts and provides consistent
and comparable information to industrial customers and end-use consumers regarding environmental impacts.
The nature of EPDs also allows summation of environmental impacts along a product’s supply chain—a
powerful feature that greatly enhances the utility of LCA-based information.
In the case of wood products, sustainable forest management certification complements the information in
an EPD, providing a more complete picture by encompassing parameters not covered in an LCA—such as
biodiversity conservation, soil and water quality, and the protection of wildlife habitat.
EPDs for wood products are available from the American Wood Council (www.awc.org) and Canadian Wood
Council (www.cwc.org) at http://www.awc.org/greenbuilding/epd.php .
•
ATHENA EcoCalculator for Assemblies
and Impact Estimator for Buildings
(www.athenasmi.org/our-softwaredata/overview/): free inventory data tool for
comparing assemblies or whole buildings, based
primarily on the widely acclaimed US Life Cycle
Inventory Database and published Canadian data.
•BEES (http://www.nist.gov/el/economics/
BEESSoftware.cfm): easy-to-use, US-based,
free tool for product-to-product comparisons;
based on proprietary, unpublished data.
•ENVEST (http://envestv2.bre.co.uk/):
UK-based, life cycle assessment-based building
design tool. It addresses only the whole
building, and provides results in highly
summarized “ecopoints.”
•Forest Industry Carbon Assessment
Tool (FICAT) (http://www.ficatmodel.org/
landing/index.html): available for download
free of charge, calculates carbon footprints of the
effects of forest-based manufacturing activities
on carbon and greenhouse gases along the value
chain.
Impact Category Indicators Table from the Softwood Lumber EPD:
The life cycle impact assessment (LCIA) results are calculated for impact category indicators such as global
warming potential and smog potential. These results provide general, but quantifiable, indications of potential
environmental impacts. The various indicators and means of characterizing the impacts are summarized in this
table.
For Life Cycle Assessment Practitioners
Impact Assessment Categories
•GaBi (www.gabi-software.com): a tool from
Germany, comprised of primarily European data.
Impact Category Indicators
•SimaPro (http://www.pre.nl/simapro):
a tool from the Netherlands; includes a
comprehensive suite of databases for building
materials applicable to the United States, Japan,
and various European countries.
Characterization Model
Global
Warming
Potential
Calculates global warming potential of all greenhouse gasses
that are recognized by the Intergovernmental Panel on
Climate Change. The characterization model scales substances
that include methane and nitrous oxide to the common unit
of kg CO2 equivalents.
Ozone
Depletion
Potential
Calculates potential impact of all substances that contribute to
stratospheric ozone depletion. The characterization model
scales substances that include chlorofluorocarbon,
hydrochlorofluorocarbon, chlorine, and bromine to the common
unit of kg CFC-11 equivalents.
Acidification
Potential
Calculates potential impacts of all substances that contribute to
terrestrial acidification potential. The characterization model
scales substances that include sulfur oxides, nitrogen oxides,
and ammonia to the common unit of H+moles equivalents.
Smog
Potential
Calculates potential impacts of all substances that contribute to
photochemical smog potential. The characterization model scales
substances that include nitrogen oxides and volatile organic com
pounds to the common unit of kg O3 equivalents.
Eutrophication
Potential
Calculates potential impacts of all substances that contribute to
eutrophication potential. The characterization model scales substances that include nitrates and phosphates to the common unit
of kg N equivalents.
Wood Specification: Life Cycle Assessment
What to Ask Suppliers
Rule of Thumb
Encourage product manufacturers to perform life cycle
assessments on their products and make the results
available. Ask product reps for LCA data and LCAbased EPDs for wood and all other products on the
bill of materials. If lacking, encourage sourcing from
manufacturers that do provide such information. Ask or
consider key questions about the data that are provided
in order to assess the reliability and applicability to
design decisions.
Examples of such questions include:
• What are the sources of the data? How much is
based on primary information obtained directly from
the operations, as opposed to databases of industryaverage data? Of the industry average data, is it
regionally specific (U.S. as opposed to Europe) and fully
transparent to users or peer reviewers?
• What assumptions are included about the
functional unit and the service life of the product(s)
in question? Do these correspond to the project at
hand?
• What is included in any life cycle assessment or life
cycle cost calculation? Sometimes, certain materials
or components are excluded, e.g., the resin in a
composite wood product.
• What is assumed about the products’ maintenance
requirements and/or impacts on building operations?
• Do the impact categories included in the results
capture the important information, or might the
results be skewed by leaving out key categories?
Resources
Normalized to wood value = 0.75
4.0
Lawrence Berkeley National Laboratory,
Design Building
High-PerformanceWood
Commercial
Steel Design
3.5
is
Systems
(http://buildings.lbl.gov):
developing a set ofConcrete
life cycleDesign
cost tools
3.0
for
improving commercial building
performance.
2.5
Whole
Building Design Guide—Life Cycle
Tools (www.wbdg.org/tools/tools_cat.
developed by the National
php?c=3):
2.0
Institute of Building Sciences in the United
States, provides a variety of life cycle cost
1.5
and assessment tools.
European
Commission, Life Cycle
1.0
Thinking (http://lct.jrc.ec.europa.eu/):
improvements to goods and services in
the form of lower environmental impacts
and reduced use of resources across all life
cycle stages. The site includes a handbook
and information about the European
Platform on Life Cycle Assessment and the
European Reference Life Cycle Database
(ELCD core database v2 with 300+
processes).
United Nations Environment Program,
Life Cycle Initiative (http://lcinitiative.
unep.fr/): aims to bring science-based life
cycle approaches into practice worldwide.
home of the International Reference Life
0.5 Data System which seeks to identify
Cycle
0.0
Air Pollution
Solid Waste
Resource Use
Energy
GWP
Water Pollution
Embodied effects relative to the wood design across all measures
Normalized to wood value = 0.75
6
Wood Design
Steel Design
Concrete Design
5
Material
Embodied
energy, ranked
by density
MJ/m3
Straw bale
31
Cellulose insulation
112
Mineral wool insulation
139
Aggregate
150
Soil-cement
819
Fiberglass insulation
970
Lumber
1,380
Stone, local
2,030
Concrete, block
2,350
Concrete, precast
2,780
Concrete (30 MPa)
3,180
Polystyrene insulation
3,770
Particleboard
4,400
Shingles, asphalt
4,930
Brick
5170
Plywood
5,720
Gypsum insulation
5,890
Aluminium, recycled
21,870
Steel, recycled
37,210
Glass
37,550
Carpet, synthetic
84,900
PVC
93,620
Paint
117,500
Linoleum
150,930
Steel
251,200
Zinc
371,280
Aluminium
515,700
Brass
519,560
Copper
631,164
Source: The Canadian Architect
Note: this table does not differentiate the impacts and efficiencies
of source energy generation used in extraction, transportation
or manufacture. For example, the Swiss Minergie rating system
(www.minergie.com) weights energy carrier and sources as follows:
Biomass (wood, biogas) 0,5 Waste heat (sewage, industry, etc.) 0,6
Fossil fuels 1,0 and Electricity 2,0.
4
Note: Cubic metres may not be an appropriate unit for comparison
between materials (not a functional unit).
3
Comparing Environmental Impact of a Wood, Steel and
Concrete Home
2
1
0
Fossil
Energy
Resource
Use
GWP
Acidification Eutrophication
Ozone
Depletion
Source: Dovetail Partners using the Athena Eco-Calculator (2014)
GREEN BUILDING RATING SYSTEM GUIDES
Smog
potential
In this graph, three hypothetical buildings (wood, steel, and
concrete) of identical size and configuration are compared.
Assessment results are summarized into seven key measures
covering fossil energy consumption, weighted resource use,
global warming potential, and measures of potential for
acidification, eutrophication, ozone depletion, and smog
formation.
In all cases, impacts are lower for the wood design. Source:
Dovetail Partners using the Athena Eco-Calculator (2014)
© 2014 |
Wood Specification:
Locally Produced Materials
Locally produced materials are often sought because they match a local design
aesthetic and can be more durable in the local climate. However, choosing local
materials also supports local economies and reduces the environmental impacts
of transportation.
For purposes of gaining credits in green building rating systems, documentation as outlined below is
important only if working within older versions of LEED (2009) or other programs where local materials
were considered to be those where all materials and components originated from within a 500 mile
radius. Documentation is now needed only for those materials sourced from within a 100 mile radius if
seeking credits under LEED v4.
Terminology
Extraction:
the removal of natural materials
from the earth for the purposes
of human use.
Harvested:
refers to all or part of a plant that
has been collected and removed
from the location of its growth.
Site of final manufacture:
the location where final assembly
of components into the building
product takes place.
Why Locally Produced Wood Adds Value
•Locally sourced materials may be more cost-effective because of reduced transportation costs, although
these savings may be offset by the higher costs associated with complying with more demanding social
and environmental legislation.
•In some jurisdictions, governments have recognized the value of wood and have put in place programs
and incentives to encourage the incorporation of wood into building design.
•The support of local manufacturers and labour forces retains capital in the community, thus contributing
to a more stable tax base and a healthier local economy as well as showcasing the resources and skills
of the region.
•Green building rating systems award credits where a prescribed percentage of locally produced
materials are used in a building’s design.
Manufacturing process:
activities associated with the
production of materials, goods, or
products.
Processing:
operations involved in the
manufacture or treatment
of a product or material.
How to Include Locally Produced Wood in Design
•Getting to know the region is central to the
practice of design. Develop relationships with
local contractors and developers to determine
where materials are from and what regional
options are available. Being familiar with local
policies that promote local materials is essential.
•Establish and maintain a library of regional
materials and manufacturers for ready access
during the design phase.
•It is important to set goals early in the design
process for the use of locally produced wood
and other materials. Assess the availability
of regional materials and determine the best
available products to minimize the project’s
GREEN BUILDING RATING SYSTEM GUIDES
environmental impacts. This may require
careful research to determine what local
products are available.
•The use of life cycle assessment tools may prove
helpful in the decision-making process because
local materials may have a significantly lower
carbon footprint than imported alternatives.
•Set appropriate local materials targets based
on the project’s budget and ensure related
requirements are captured in the construction
documents along with approved alternatives.
Wood Specification: Locally Produced Materials
What to Ask Suppliers
• Regarding the materials used to make the
product, where were they extracted, harvested,
or processed?
• Where was the final product manufactured?
• How far are these locations from the project site?
• How were the materials transported to the project
site? Were they delivered by rail, water, or truck?
• Documentation, such as a letter from the
manufacturer, or environmental information
sheets, demonstrating the proportion of local
materials in the total assembly of the product
(based on weight) must be acquired from the
manufacturer or the supplier.
Photo: Moresby Creative
Procedure
• When working with green building rating
systems, it is important to establish and track
information about the manufacturers and the
product costs. It is also important to document
the distance between the project site and the
manufacturers’ locations, and the distances
between the manufacturers’ locations and the
extraction, processing, and manufacturing sites.
Record the mode of travel for each raw material
in each product too.
• Material technical data must be acquired from
suppliers, usually in the form of environmental
information sheets and technical spec sheets.
• Where appropriate, maintain a list of material
costs, excluding labor and equipment.
• If working wih LEED 2009 or other rating
systems patterned after LEED, for assemblies
or products made with components originating
from within a 500-mile (800-km) radius of the
project site. If working within LEED v4, keep
data only for products sourced within a 100
mile radius.
• The percentage of locally produced materials
is calculated by dividing the cost of locally
produced materials by the total cost of
materials. Total material costs are obtained
either by multiplying total construction costs by
0.45 or by calculating the actual material costs,
if known.
• If only a fraction of a product or material is
extracted, harvested, recovered, processed, and
manufactured locally, then only that percentage
(by weight) must contribute to the regional
value. Furniture may be included in calculating
the percentage of locally produced materials.
• Life cycle assessment tools can provide
comprehensive information about the impacts
of using local products. Most life cycle
assessment tools provide regionally specific
data.
GREEN BUILDING RATING SYSTEM GUIDES
percentage of local materials =
total cost of local materials ($)
total material cost ($)
× 100
Pre-design:
calculate baseline budget
Design: estimate the total
cost of materials for site work
and construction sections.
or
Design: use the default budget
if seeking to avoid breaking out
material and labour costs.
Design: on a map, draw a 500-mile
(800-km) radius around the project
site, and identify major extraction and
manufacturing sites.
Contract Documentation: starting
with big-ticket materials, specify
products from regional sources.
Construction: track regional materials
on a spreadsheet. This process can
be included in a larger analysis of all
materials applicable to resource credits
because the regional materials may
contribute to other credits as well.
Calculate percentages for points,
and reassess as needed.
Throughout: revisit the project’s
budget calculations throughout design
and construction to ensure the project
is on track to achieve its goals.
© 2014 |
Wood Specification:
Recycled Materials
Recycled content products are made from materials that would otherwise
have been discarded either during the manufacturing process (pre-consumer)
or at the end of service life (post-consumer). Specifying recycled content products
plays an essential part in reducing the amount of waste that goes to landfills,
the energy consumption and greenhouse gas emissions associated with new
product manufacture, and the impacts of ecosystem degradation associated
with resource extraction.
Terminology
Recycled content:
the proportion, by mass, of
recycled material in a product
or packaging. Only pre-consumer
and post-consumer material is
considered as recycled content,
as defined under ISO 14021
Environmental Labels and
Declarations—Self-Declared
Environmental Claims
(Type II Environmental Labelling).
Pre-consumer recycled material:
material diverted from the waste
stream during a manufacturing
process. Materials generated
in a process and capable of
being reclaimed within the same
process (such as rework, regrind
or scrap) are excluded.
Post-consumer recycled material:
material generated by households
or by commercial, industrial, or
institutional facilities in their
role as end users of a product
that will no longer be used for its
intended purpose.
Assembly recycled content:
the recycled proportion of
a material that is calculated
by dividing the weight of the
recycled content by the overall
weight of the assembly.
Resources
Construction Specifications Institute,
GreenFormat (www.greenformat.com):
database of products containing
recycled content.
Scientific Certification Systems
(www.scscertified.com/gbc/
recycledmaterials.php): products made
from pre-consumer or post-consumer
material can qualify for recycled
content certification.
GREEN BUILDING RATING SYSTEM GUIDES
The use of wood products with recycled content is relatively straightforward.
Products such as:
•particleboard
• oriented strand board
• parallel strand lumber
are cost effective, familiar to the trades, and can contribute a high proportion of
recycled content to the overall calculations. Furniture is generally not included in
calculating the percentage of recycled content.
Why Recycled Materials Add Value
•Building products that include some or all recycled content reduce the need for virgin materials in new
construction. Using recycled materials reduces the need to landfill these materials. It also reduces the
environmental impacts associated with extracting and processing virgin materials.
•Buying recycled-content building products helps to ensure that materials collected in recycling
programs will be used again in the manufacture of new products. Benefits of maximizing the
recycled content in materials include the ability to:
›› D
emonstrate performance against corporate responsibility and sustainability policies
without incurring a cost premium
›› Reduce materials cost; e.g., where locally reprocessed demolition materials are cheaper
than virgin materials
›› Provide a competitive edge through differentiation
›› Make reclamation and recycling more economic
›› Satisfy the values held by clients and their employees
›› Complement other aspects of sustainable design
•Green building rating systems award credits where a prescribed percentage of materials
containing recycled content is used in a building’s design.
How to Include Products Containing Recycled Content in Design
•Many products with higher levels of recycled
content are available from mainstream
manufacturers—who subject the products
to the usual tests—in high volumes, and at
costs that are competitive with equivalent
products containing less recycled material.
•It is important to set goals early in the
design process and to document them in the
specification documents as part of the project’s
overall green building goals. Set appropriate
recycled content targets based on the project’s
budget and ensure related requirements are
captured in the construction documents along
with approved alternatives.
•Increasing the recycled content of building
materials need not impact design nor restrict
the choice of products. Simply select products
containing higher levels of recycled material in
place of products containing lower amounts.
•The use of life cycle assessment tools may prove
helpful in the decision-making process because
some materials with recycled content may
require more frequent care and maintenance.
•Coordinate recycled material procurement with
a construction waste management plan in order
to make use of on-site salvaged deconstruction
and demolition waste.
Wood Specification: Recycled Materials
What to Ask Suppliers
•Material technical data must be acquired from
suppliers, usually in the form of environmental
information sheets and technical spec sheets
that clearly spell out the proportion of recycled
content in the total assembly of the product
(based on weight). Recycled content percentages
should be provided for post-consumer
and pre-consumer content.
•Make sure that the supplier provides the
manufacturer’s contact information so that
additional information can be obtained
if required.
•14021 Environmental Labels and
Declarations—Self-Declared Environmental
Claims (Type II Environmental Labelling) is the
international standard used to verify recycled
content in products.
Photographer: Peter Powles
Procedure
Where possible, take ownership of core tasks, including:
•Estimate, at key stages in the project, the
potential baseline and good practice levels of
recycled content for the project as a whole.
•Identify opportunities that might deliver “quick
wins” in terms of offering higher recycled content,
and determine how the project can meet the
client’s requirement.
•Negotiate and agree how the contractor will
meet a request for good practice; e.g., agree on
the actual levels of recycled content to be used,
through discussions with contractors and project
cost consultants.
•Prepare specifications that stipulate the
requirements to be met by the contractor
and trades.
•Advise the client about the documentation
process and the need to check that the product
complies with the project requirements.
•Establish and track information about the
manufacturer, product cost (excluding labour
and equipment), and proportion of pre-consumer
and post-recycled content in the raw materials
of each product.
GREEN BUILDING RATING SYSTEM GUIDES
recycled content value ($) =
(% post-consumer recycled content ($) × materials cost) +
(% pre-consumer recycled content ($) × materials cost)*
* = some rating systems may apply a factor for pre-consumer recycled content
Pre-design: calculate baseline budget
Design: estimate total material costs
for site work and construction sections.
or
Design: use the default budget
method of 45% of materials.
Design: start with big-ticket items: identify materials
and products with recycled content, integrate into design,
and specify early.
Construction: track recycled content of materials in a
spreadsheet with other materials; calculating percentages for
points, and reassess as needed.
Throughout: revisit the project’s budget calculations
throughout design and construction to ensure the project is
on track to achieve its goals.
© 2014 |
Wood Specification:
Terminology
Refurbished materials:
products that could have been
disposed of as solid waste;
refurbishing includes renovating,
repairing, restoring, or generally
improving the appearance,
performance, quality, functionality,
or value of a product.
Remanufactured materials:
items that are made into other
products; e.g., framing off-cuts
that are chipped and used as
landscape mulch.
Salvaged Materials
Salvaging and reusing wood and wood-based products reduces demand for virgin
materials and reduces waste, thereby lessening impacts associated with the
extraction and processing of virgin resources.
A considerable portion of the wood used in construction (such as formwork,
bracing, and temporary structures) and the wood in demolished buildings can
be salvaged and reused. Reuse strategies divert material from the construction
waste stream, thus reducing the need for landfill space and mitigating
environmental impacts associated with water and air contamination.
Salvaged materials or reused
materials:
those recovered from existing
buildings or construction sites and
reused; e.g., structural beams and
posts, flooring, doors, and cabinetry.
Resources
Old to New Design Guide, Salvaged
Building Materials in New Construction
(www.lifecyclebuilding.org) detailed
reviews of the use of salvaged materials
in real-life case studies in British
Columbia.
Green Building Resource Guide
(www.greenguide.com/about.html)
and Salvaged Building Materials
Exchange (www.greenguide.com/
exchange/): a database of >600 green
building materials and products selected
for their usefulness to the design and
building professions, and a searchable
online database of green building
products.
Building Materials Reuse Association
(www.bmra.org): represents companies
and organizations involved in the
acquisition and/or redistribution
of used building materials.
Used Building Materials Exchange
(www.build.recycle.net): free online
marketplace for buying and selling
recyclables and salvaged materials.
GREEN BUILDING RATING SYSTEM GUIDES
Why Salvaged Materials Add Value
Greater Texas Foundation, Bryan Texas
Photo courtesy of Page
•Salvaged materials such as structural members and flooring add significant character to design.
Frequently, salvaged wood products are sourced from old-growth timbers; these offer close grain finish
and are extremely hard wearing.
•Some salvaged materials are more costly than new materials because of their “one of a kind”
quality and because of the high cost of labour involved in the recovery and refurbishing processes.
•Reused materials refer to items that were “fixed” components on-site before construction began.
To comply with most rating systems, these items must no longer be able to serve their original
functions and must then be installed for a different use or in a different location.
•Demolished wood is considered salvaged wood. However most rating systems treat wood that
continues to serve its original function (e.g., walls, ceilings, flooring) in a renovation project
under a different category.
How to Include Salvaged and Reused Wood in Design
•The incorporation of salvaged materials as
a design strategy affects cost estimates, the
demolition phase (if salvaging from the project
site), and the ultimate design development
of the project.
and building areas to be salvaged can be
creatively and efficiently worked into the
design, and opportunities to bring in salvaged
materials from off-site can be incorporated
into the project.
•Coordination among the owner, design team,
and contractor should begin early in the
pre-design phase and continue through design
development. Then knowledge of the site
•Rating systems award credits for a prescribed
percentage (by cost) of both on-site and off-site
salvaged or reused materials.
Wood Specification: Salvaged Materials
Procedure
•For rating system documentation purposes,
maintain a list of reused and salvaged materials
and corresponding costs.
•The percentage of salvaged and reused wood
employed on a project is based on the cost of
salvaged/reused materials divided by the total
cost of materials. The cost will be the actual
cost paid or, if the material came from on-site,
the replacement value. The replacement value
can be determined by pricing a comparable
material in the local market (excluding labour
and shipping). When the actual cost paid for
the reused or salvage material (from either
on-site or off-site) is below the cost of a
comparable new item, use the higher value
in the calculations.
•Furniture may be included if it is used
consistently in the calculations of both
salvaged materials and total materials used
on a project.
percentage salvaged/reused materials =
cost of reused materials ($)
total material cost ($)
× 100
Pre-design: assess opportunities for reusing
materials and the extent of site demolition
involved and set goals accordingly.
Design: incorporate salvaged or reused materials
into the design. Working with salvaged structural
lumber requires the involvement of an experienced
engineer. More than usual structural redundancy
may need to be built into the design.
Contract documentation: identify resources
and outline measures for the use of salvaged
materials. Assemble a spreadsheet to track the
proportion of salvaged materials in the project
(as a function of materials cost, excluding labour).
Tender: work with the contractor to locate
sources for these materials and document and
track their cost and quantity during construction.
This recordkeeping will aid the project team in
the credit submission process.
Wood Salvaged from Warehouse
Seattle District headquarters for the U.S. Army Corps of Engineers is a LEED Gold project which was partially
funded through the U.S. GSA’s Design Excellence Program. All of the wood used in the project was salvaged
from a 1940s-era warehouse that previously occupied the site—a total of 200,000 board feet of heavy
timber and 100,000 board feet of 2x6 tongue and groove roof decking.
Federal Center South – Building 1202 Seattle, WA Architect: ZGF Architects LLP
Photo: Benjamin Benschneider
What to Ask Suppliers
•Ensure that all costs are declared at the outset. Some salvaged materials are offered at prices that
appear to be cost effective, but some costs may be hidden, such as the need for reprocessing.
•When dealing with salvaged wood products, clarify the presence of any toxic substances such as lead
or asbestos, and ensure all costs and responsibilities for decontamination are taken into account.
•Confirm that documentation is available for the product’s provenance and history.
Construction: advise the builder and trades
of the scope and requirements of the salvaged
products; alert them to specific responsibilities.
Track materials and products that have been
reclaimed, salvaged, or reused.
GREEN BUILDING RATING SYSTEM GUIDES
© 2014 |
Wood Specification:
Acoustics
For centuries, wood has been the material of choice for architects and designers
intent upon delivering the highest quality of acoustic performance. From a violin
to an entire concert hall, wood plays a role in delivering memorable acoustical
experiences. Wood produces sound by direct striking and it amplifies or absorbs
sound waves that originate from other bodies. For these reasons, wood is an
ideal material for musical instruments and other acoustic applications, including
architectural ones.
Why Acoustic Performance Adds Value
•Architects and designers have a responsibility to design functional and safe environments. It is very
difficult, if not impossible, to meet these goals without considering acoustics. Moreover, it is extremely
challenging to deal retroactively with poor acoustic environments. Doing so can severely impact
a building’s value.
•Privacy is a major issue for building occupants. Designers must provide for adequate levels of sound
insulation. Acoustical problems arise when sound transmits through the structure or when reverberation
occurs via hard reflective surfaces. Sometimes fire safety design features can have deleterious effects
on sound transmission because of the requirements for hard, non-combustible materials, wall and
floor penetrations, etc.
Terminology
Sound Transmission Class: determined in accordance with
American Society for Testing and
Materials’ ASTM E 413 Standard
Classification for Rating
Sound Insulation.
•Post-occupancy evaluations of buildings have revealed that poor acoustic performance is a common
problem in buildings with large areas of hard, acoustically reflective surfaces. Such surfaces are
frequently found in green buildings where the use of absorbent surfaces is often minimized due
to indoor air quality concerns.
•Wood is not as acoustically lively as other surfaces and can offer acoustically absorptive qualities.
Generally, a wood-finished building is not as noisy as a complete steel or concrete structure.
•Most green building rating systems do not recognize the importance of acoustic performance.
Impact Insulation Class:
calculated according to
American Society for Testing and
Materials’ ASTM E 989 Standard
Classification for Determination
of Impact Insulation Class.
Post-occupancy evaluation: involves systematic evaluation
of opinion about buildings in
use, from the perspective of the
people who use them. It assesses
how well buildings match users’
needs, and it identifies ways to
improve building design and
performance, and fitness
for purpose.
Resources
www.acoustics.com :
provides a comprehensive range
of resources including a database
of products, design guides, and
best practices.
GREEN BUILDING RATING SYSTEM GUIDES
Richmond Olympic Oval Roof
How to Include Acoustic Performance in Design
•Acoustics are integral to the functioning of
almost every type of indoor environment, from
open offices to worship centers. Some building
environments can even become dangerously
loud and therefore unsafe for the occupants.
In order to effectively address these issues,
building acoustics should be considered in
the design phase.
•Optimal acoustic design must consider a wide
range of factors, such as building location
and orientation, planning and location of
sound-sensitive functions, adequate insulation
of partitions, insulation or spatial separation
of noisy mechanical equipment, and measures
to enhance audibility.
•To determine the effects of a material’s surface
on the acoustics, the acoustic absorption and
scattering properties of the material’s surface
are measured. Any unabsorbed sound energy is
reflected back into the space. Not only does the
amount of sound energy reflected by a surface
affect the sound field, but where the energy is
reflected to is also a major factor. The extent to
which sound energy is scattered over a defined
area, relative to absorption, is of importance
to acousticians.
Wood Specification: Acoustics
What to Ask Suppliers
•Acquire Sound Transmission Class and Impact
Insulation Class ratings for key components and
assemblies, and for any potential interior finishes
used as acoustical controls.
•Learn about any synergistic environmental
benefits, such as indoor air quality performance
and whether the product is certified by
a third-party forest certification system.
Procedure
•Consider ambient noise issues during
schematic design: site the building, and the
zone spaces within the building, to provide
occupants with protection from undesirable
outside noise.
•Specify in the contract documents an
appropriate Sound Transmission Class
rating of perimeter walls in terms of
response to external noise levels.
•Provide noise attenuation of the structural
systems and implement measures to
insulate primary spaces from impact noise.
•Mitigate acoustical problems associated
with mechanical equipment, and mitigate
noise and vibration associated with
plumbing systems.
•Specify acoustical controls to meet the
acoustical privacy requirements.
•Specify measures to meet speech
intelligibility requirements for the various
spaces and activities.
•If in doubt about any acoustical issue,
retain the services of a qualified acoustics
expert.
Standards and Best Practices for
Acoustic Design in Buildings
Building codes used in the United States generally
require sound isolation for multiple occupancy
dwelling units. A Sound Transmission Class (STC)
of not less than 50 is commonly specified. However,
it is recognized that sounds may still be audible,
though speech not understood, on the other side
of a wall insulated to STC 50. For this reason, an STC
of 60 is recommended in sensitive areas. Canadian
research has identified the following sound-insulation
objectives for multi-family buildings.
• Inter-unit walls and floors: Sound Transmission
Class 55 or higher
University of Washington
In 2012, the University of Washington in Seattle added nearly 1,700 student housing beds by constructing
three residential halls and two apartment buildings, all of which include five stories of wood-frame
construction over two stories of concrete. Designed by Mahlum Architects and winner of a recent
WoodWorks Wood Design Award, the 668,800-square-foot project is the first of four phases planned
to add much-needed student housing to the urban campus.
“Acoustics are important for any multifamily housing project, but especially for student housing,” says
Anne Schopf, FAIA, a design partner with Mahlum. “Mitigation measures must be weighed against
budget, which is why we brought in experts from Seattle-based SSA Acoustics for the design of this
project.”
Because they knew single stud walls would not provide adequate performance, SSA recommended
staggered stud walls between residential units. Since there is no rigid connection between the gypsum
board on each side (except at the plate), a staggered stud wall performs better than a single stud wall.
Double stud walls perform better than a staggered stud design because plates are separated by an air
space, so they used double stud walls between residential units and common spaces (e.g., lounges,
staircases, and elevators) and service areas.
In the floor/ceiling assembly, they paid careful attention to the installation of resilient channels, which
are often one of the main causes of failed floor/ceiling assemblies from an acoustical standpoint. In fact,
there is a difference of 8 to 10 IIC and STC points between assemblies with resilient channels versus
those without.
Channel installation has fairly straightforward requirements; for example, screws for the gypsum board
should never touch the framing behind the resilient channel.
“We used enhanced acoustical walls between rooms in the same unit,” says Mohamed Ait Allaoua,
managing partner of SSA Acoustics. “Although not a typical approach in multifamily buildings, this
is important in student housing projects where people within a relatively small space have different
needs—if one student wants to watch TV in the living room, for example, while another is studying in
the bedroom.”
• Inter-unit “hard” floors: Impact Insulation
Class 55 or higher
• Inter-unit carpeted floors: Impact Insulation
Class 65 or higher
S ources:International Building Code (Model Code), Chapter 12.
Burrows, J. and Craig, B. 2005. Sound Control in Multi-Family
Wood-Frame Buildings. (http://www.soundivide.com/uploads/
content_file/multi-family_sound-control-en-277.pdf)
GREEN BUILDING RATING SYSTEM GUIDES
© 2014 |
Wood Specification:
Passive Design
and Framing Techniques
Terminology
Passivhaus standard:
The most rigorous European
standard, Passivhaus, regulates
input energy to a maximum 0.55
MBTU/ft2/y (15 kWh/m2/y) for
heating/cooling/ventilation.
A building that qualifies for this
standard has to meet clearly
defined criteria, which include
(for a building constructed at a
latitude of 40 to 60˚ in northern
Europe):
•A total energy demand for space
heating and cooling of less than
0.55 MBTU/ft2/y (15 kWh/m2/y)
•A total primary energy use for all
appliances, domestic hot water,
and space heating and cooling
of less than 4.4 MBTU/ft2/y
(120 kWh/m2/y).
Passive design building:
Passive design buildings share
core features with Passivhaus in
that they rely on four common
strategies:
Passive design is an approach to building design that uses the building
architecture to leverage natural energy sources, minimize energy consumption,
and improve thermal comfort. Passive buildings rely heavily on high-performing
building envelope assemblies and passive solar energy.
Wood is an attractive material for passive design because of how it combines
thermal mass with a number of performance merits, including water resistance,
structural integrity, and finish quality.
Why Passive Design Adds Value
•The ultimate goal of passive design is to fully eliminate requirements for active mechanical systems
(and associated fossil fuel-based energy consumption) and to optimize occupant comfort.
• Passive design and optimal building envelope performance can:
›› Help reduce or even eliminate utility bills
›› Improve the quality of the interior environment
›› R educe greenhouse gas emissions associated with heating, cooling, mechanical ventilation,
and lighting
›› Reduce the need for mechanical systems and their associated costs
›› Make alternative energy systems viable
How to Include Wood as Part of Passive Strategies in Design
Optimum value engineering (OVE) uses advanced
principles to optimize the use of wood for framing by:
•Passivhaus pre-fabricated wall assembly with
effective insulation reaching as high as R32
•A high level of utilization of solar
and internal gain
•Expanding the spacing between exterior and
interior wall studs to as much as 24 inches
(61 cm) on-center
•Helped by cross-laminated technology and
quality
•An excellent level of air tightness
•Energy efficient framing
•Good indoor air quality
Structural insulated panels and pre-fabricated
wood panels:
•High-performing wood-frame, aluminum-clad,
triple-glazed windows
•A high level of insulation, with
minimal thermal bridges
•Most structural insulated panels consist
of an insulating foam core sandwiched
between oriented strand board. Structural
insulated panels are gaining market share in the
residential and light commercial building market
because they are quick to assemble and provide
excellent energy performance
Resources
Passive House Institute US
www.passivehouse.us
Passive House Institute
www.passiv.de
Does research and development on
efficient energy use and the design
and construction of passive houses.
•Wall panels reduce thermal bridging/migration,
control air leakage, and keep heating and
cooling costs to a minimum compared
to a conventionally framed wall
Airtight construction—build tight then ventilate right:
•The following areas of the building envelope
should be sealed, caulked, gasketed, or
weather-stripped to minimize air leakage:
›› Joints around fenestration and door frames
›› J unctions between walls and foundations,
between walls at building corners, between
walls and structural floors or roofs, between
walls and roof or wall panels
›› All other openings in the building envelope
›› P assive design framing and carbon-neutral
wall assembly
GREEN BUILDING RATING SYSTEM GUIDES
• Insulation, including wood-fibre insulation
Wood Specification: Passive Design and Framing Techniques
What to Ask Suppliers
•Ask if key wood product suppliers are able to
participate in the integrated design process in
order to discuss innovative methods of employing
wood in the project.
•Request information about the framing techniques
available for the proposed project.
Procedure
Step-by-step approach to incorporating
passive strategies in building design:
Pre-design: perform bioclimatic and solar
site analyses
Pre-design: organize an integrated design
process with key project team members in
order to review passive design strategies
that include (but are not limited to):
• Passive solar power
• Orientation of building
• T hermal performance and effective
insulation of the building envelope
• Location and size of windows
• On-site renewable energy generation
• HVAC system size requirements
Design: conduct an energy simulation
model with the help of a certified energy
advisor to analyze the various design and
construction strategies and to verify that
the project will meet the proposed energy
use targets.
Kiln Apartments
Kiln Apartments, Portland, OR
GBD Architects
Photo credit: Eckert & Eckert Photography
Kiln Apartments is an 18,000 square foot building, located in a pedestrian- and bicycle-friendly
neighborhood in North Portland featuring 19 for-lease apartments and ground floor retail. Inspired
by pleasant childhood memories in the Pacific Northwest, the apartments are designed to evoke the
comfortable qualities of a well-crafted, single-family home with an eclectic mix of personal touches.
Kiln Apartments was a research and design effort to develop the most energy efficient market-rate
apartment building possible. It is pursuing an aggressive, energy efficiency program called “Passive
House.” Originated in Germany in the 1990s as Passivhaus, there are approximately 20,000 buildings
constructed to meet this standard (almost exclusively in Europe). Energy performance goals for the
project are ambitious; Kiln Apartments is seeking to become one of the largest Passive House certified
buildings in the United States. As a point of reference, certification for this building will require energy
performance that is approximately 65-75 per cent better than Portland’s already industry leading code
requirements.
Design strategies include:
A highly insulated envelope;high-performance, triple-pane wood windows; space heating through
wall-mounted, hot water radiant heaters served from solar thermal roof panels; continuous (24 hours a
day) ventilation through a centralized heat recovery ventilator; and deeply inset, south-facing windows
protected from unwanted solar heat gain by sunshades. Kiln Apartments construction was completed in
June 2014.
source: www.gbdarchitects.com/portfolio-item/kiln-apartments/
What is Integrated Design and
Why is it Important for Passive Design?
An integrated design is a design in which all major components of the building are considered and
designed as a totality, i.e., as an interdependent system. Integrated design means optimizing the entire
system, not just parts, with complete analysis of potential synergies and trade-offs; for example, higher
building envelope performance can lead to reductions in mechanical equipment size and long-term
operating costs.
Cross-laminated timber (CLT)
Photo credit FPInnovations
GREEN BUILDING RATING SYSTEM GUIDES
© 2014 |
Wood Specification:
Certified Wood
Terminology
Chain of custody:
a procedure for tracking a product
from the point of harvest or
extraction to its end use, including
all successive stages of processing,
transformation, manufacturing,
and distribution.
Sustainable forestry:
management that maintains and
enhances the long-term health of
forest ecosystems for the benefit
of all living things while providing
environmental, economic, social,
and cultural opportunities for
present and future generations.
Resources
Forest certification verifies the sustainability of forest management. Third-party
chain-of-custody certification traces wood material from point of harvest to its
end use, including all stages of processing, transformation, manufacturing, and
distribution; it may also include on-product labelling. More than 50 independent
forest certification programs exist worldwide, reflecting the diversity of forest
types, ecosystems, and owernership.
The two largest umbrella certification programs are the Forest Stewardship
Council (FSC) and the Programme for the Endorsement of Forest Certification
(PEFC). PEFC endorses the Canadian Standards Association (CSA), the Sustainable
Forestry Initiative (SFI) and the American Tree Farm System (ATFS), three standards
functional in North America in addition to FSC. While the various programs differ,
most promote sustainable forest management through principles, criteria, and
objectives.
Why Certified Wood Adds Value
•Wood is an excellent environmental choice for any new construction or renovation project. It grows
naturally. It is renewable and recyclable. Wood from well-managed forests is sustainable over the
long term. Forest certification shows customers that the wood comes from well-managed forests.
•By providing a credible means to assure customers that wood products come from legal and responsible
sources, third-party forest certification can provide an incentive for sustainable forest management and
continual improvement of forest practices.
www.dovetailinc.org/files/
DovetailCertReport0310b.pdf
a summary report examining
and comparing the various forest
certification programs operating in
North America.
www.sfiprogram.org
provides information about the
Sustainable Forestry Initiative
(SFI) forest and wood certification
program.
www.us.fsc.org
provides information about the
Forest Stewardship Council (FSC)
forest and wood certification
program.
www.forestfoundation.org/
american-tree-farm-system
provides information about the
American Tree Farm System (ATFS)
forest certification system.
www.csasfmforests.ca
provides information about the
Canadian Standards Association
(CSA) forest and wood certification
program.
GREEN BUILDING RATING SYSTEM GUIDES
How to Include Certified Wood in Design
• Green rating systems offer optional credits
for including third-party certified wood-based
materials among the building components;
the contribution of certified wood to total
cost of installed materials determines
the points awarded. Most rating systems
include wood used in structural framing and
in general dimensional framing, flooring,
subflooring, wood doors, and finishes.
• There are four primary forest certification
programs operating in North American
today: SFI, FSC, CSA, and ATFS. All but FSC
are endorsed by PEFC, a European-based
organization that evaluates and provides
mutual recognition of forest certification
standards worldwide. Certification
in all cases requires third-party verification
against a published, transparent standard.
Different rating systems allow for different
certification programs, with some more
inclusive than others.
• The feasibility of using certified wood should
be determined at the outset of the design
process. Establish a project goal for certified
wood products that is consistent with the
desired rating system. Identify components
of the design that can use certified wood,
and research the availability of wood
products from certified sources that can
support design goals.
Wood Specification: Certified Wood
Percy Norman
Aquatic Centre
Procedure
•Determine which certification system the
wood will be sourced through.
During the 2010 Olympic and Paralympic Winter
Games, the new Percy Norman Aquatic Centre
in Vancouver, British Columbia was a venue for
curling events and a marshalling area for athletes.
In keeping with the Vancouver Board of Parks’
ongoing commitment to sustainability, this facility
was built to meet Leadership in Energy and
Environmental Design (LEED®) Gold criteria.
•Specify the requirement for certified wood
in the contract documents.
•Track certified wood purchases and
retain any associated chain-of-custody
documentation.
•Collect copies of vendor invoices for each
certified wood product.
The Aquatic Centre features a solid wood roof
supported on Douglas-fir glulam beams that
span up to 130 ft (43 m) across the main pool
area. At the east end of the building, the beams
are supported on outwardly inclined Douglas-fir
glulam columns of similar cross-section, with steel
structure V supports picking up the other end
of the beams. It features glulam beams made
from certified wood.
•Maintain a list that identifies the percentage
of certified wood in each purchase.
•Develop a spreadsheet for calculating
the amount of new wood, pre-consumer
recycled wood, and certified wood needed
for the project. For each wood product,
specify the percentage of certified wood
to be used, based on cost.
percentage of certified wood =
certified wood material value ($)
total new wood material value ($)
x 100
P
re-design: check to see which certified wood
products are readily and locally available and
work these into the design.
P
re-design: check which forest certification
is acceptable. This will depend upon the green
building rating system the project is following
(many have adopted an inclusive approach).
Design: focus on big-ticket items that can
contribute to multiple credits.
-orWhere dealing with large volume of a certain
type of wood product (e.g., framing lumber),
price regionally available certified wood
to determine whether a rating system credit
can be achieved.
-orWeigh the value of using certified wood
against the use of local wood that has
other environmental merits. Do a life cycle
assessment to determine the best option.
Design: create a baseline budget and assess
the goals.
Contract Documentation: tabulate and
calculate the required percentage of certified
wood in a spreadsheet. Reassess as needed.
Construction: advise the builder and trades of
the scope and requirements of the certified wood
products. Track materials and products that are
required to be from certified sources and obtain
certificates as necessary.
GREEN BUILDING RATING SYSTEM GUIDES
What to Ask Suppliers
• Identify vendors, suppliers, and manufacturers
and coordinate with them early to ensure a supply
of the “brand” of certified wood that is acceptable
to the particular green building rating system.
Programme for the Endorsement of Forest
Certification (PEFC) (www.pefc.org)
• P EFC is the world’s largest certification umbrella
organization. As an international nongovernment organization, it supports sustainable
forest management through assessment and
endorsement of national forest certification
schemes.
• A sk for copies of all relevant chain-of-custody
certificates and confirm they are in good order
for all relevant products prior to purchasing them.
• The market currently does not hold competitive
materials to wood (concrete, steel, glass, plastics)
to the same level of accountability for chain-ofcustody certification. Ask suppliers of non-wood
products about the level of stewardship and
standards that apply to these other materials.
forest management certification:
• The standards of the Canadian Standards
Association (CSA), the Sustainable Forestry
Initiative (SFI) and the American Tree Farm
System (ATFS) are endorsed by PEFC.
SFI-01569
Sustainable Forestry Initiative (SFI)
(www.sfiprogram.org)
Canadian Standards Association’s (CSA)
Sustainable Forest Management Standards
(www.csasfmforests.ca)
• SFI is a non-profit organization that promotes
responsible forest management in the USA
and Canada.
• CSA is an independent, not-for-profit organization
accredited to develop standards in Canada.
• It offers a product label and a chain-of-custody
certification standard.
• C
AN/CSA-Z809 and CAN/CSA-Z804 are
both National Standards of Canada based
on internationally recognized criteria that are
adapted to local conditions through a transparent
public participation process.
• For a land manager or manufacturer to be SFIcertified and use the SFI label on products, it
must pass an independent third party audit that
verifies compliance with SFI’s high standards.
• CSA offers a PEFC product label and
a chain-of-custody certification standard.
American Tree Farm System
(www.forestfoundation.org/american-tree-farmsystem)
Forest Stewardship Council (FSC)
• ATFS is the largest and oldest sustainable family woodland system in America, internationally recognized, meeting strict third-
party certification standards.
(https://us.fsc.org)
• F SC is an international non-governmental
organization that promotes responsible
management of forests.
• It endorses regional standards based on its
international principles and criteria adapted
to local conditions.
• ATFS is a program of the American Forest Foundation.
• It offers a product label and a chain-of-custody
certification standard.
© 2014 |
Wood Specification:
Construction
Waste Management
Terminology
Source-separated collection:
requires individual, clearly labelled
bins for sorting each recyclable
material on site.
Commingled collection:
allows mixed recyclables to be
collected on site and sorted at the
depot. While convenient for small
projects, diversion rates tend to
be lower than source-separated
recycling.
Construction waste
management plan:
The objectives of construction waste management are to divert construction and
demolition debris from landfills and give it a higher value purpose. Recyclable
and recovered wood-based materials can be directed to various manufacturing
processes, while reusable materials are diverted to the appropriate use.
Why Construction Waste Management Adds Value
•Reducing, reusing, and recycling clean wood waste reduces demand for virgin resources, minimizes
the environmental impacts associated with resource extraction, processing, and transportation, and
alleviates pressure on limited landfill space.
•The recycling of wood waste is straightforward and affordable. Most urban centres provide recycling
services for clean (non-treated) wood waste. Wood chip products are typically sold as hog fuel and
also sold for animal bedding, composting, and mulching.
•Reducing waste can reduce costs associated with transporting and disposing of waste. Changes in the
economics of recycling—i.e., the advent of market competition for both raw and recycled materials, increased
disposal costs, more stringent waste disposal regulations, and decreasing landfill capacity—have made the
development of a waste management plan an important consideration in the design process.
a document specific to a building
project which outlines measures
and procedures that divert
construction waste materials from
landfill and incineration facilities.
Tipping fees:
charged by a landfill for disposal of
waste; typically quoted per tonne.
Resources
Whole Building Design Guide
www.wbdg.org/resources/cwmgmt.
php
US EPA Construction &
Demolition Materials
Reducing and recycling C&D
materials conserves landfill space,
reduces the environmental impact
of producing new materials, creates
jobs, and can reduce overall building
project expenses through avoided
purchase/disposal costs. Changing
how we think about these materials
will create a more sustainable
future.
http://www.epa.gov/epawaste/
conserve/imr/cdm/
Building Materials Reuse Association
(www.bmra.org): resources to facilitate
building deconstruction and salvage of
building materials in North America.
GREEN BUILDING RATING SYSTEM GUIDES
How to Include Construction Waste Management in Design
•Waste minimization informs the entire design
and construction process. The creation of a
waste management plan during the design
phase embeds the goals of the project from
the outset. For example, demolished wood on
the site can either be repurposed in the new
design or recycled, depending on its quality.
•Waste minimization starts with strategies
established during the preliminary design phase
that are aimed at not creating waste in the
first place. Efficient design, the use of shopfabricated components, modular construction,
and ordering materials cut to size will ensure
waste is minimized and may save money in
transportation costs.
•Wood lends itself to dismantling, but designing
for disassembly requires upfront thinking.
Structural wood members in particular can
typically be reclaimed and reused for the same
or similar purposes with only minor waste.
•Ensure that products are installed in a way
that will not generate waste in the future.
For example, nailing rather than gluing the
wood flooring offers easier removal later.
•Reuse materials where possible by developing
a down-scale plan. A down-scale plan
identifies the products to be reused and
describes their subsequent destination
for them, including contact information
for service providers and details of the
logistics.
•Consider how off-cuts can be used, such
as for shims or as chips for landscape mulch.
•Generally, construction waste includes recycled
and/or salvaged non-hazardous construction and
demolition debris. Treated wood is not recyclable.
To minimize the need to deal with treated wood
waste, ensure the design includes adequate
weather protection for exposed wood features,
and plan for easy ongoing maintenance.
Wood Specification: Construction Waste Management
What to Ask Suppliers
•From preliminary design onward, it is important
to liaise with suppliers regarding waste
management solutions. Having a solid
understanding of manufacturing processes,
how materials are delivered, and the waste they
generate during installation is necessary prior
to finalizing the project specification documents.
•Work with manufacturers to minimize unnecessary
packaging and make arrangements for pallets
to be picked up after use.
•Ask suppliers for information about a product’s
recyclability and end-of-life impacts.
•Ask if suppliers have a take-back program
to minimize the generation of waste in the future.
Construction Waste, the Numbers
Procedure
“Municipal Solid Waste (MSW) and Construction and Demolition (C&D) Wood Waste Generation
and Recovery in the United States” by Dovetail Partners Inc.
•Document the diversion of construction waste
by tracking all construction waste by type,
the quantities of each type diverted, and the
total percentage of waste diverted from
landfill disposal.
The softwood and hardwood forests of the United States provide wood products that are used in
many applications including: lumber and other building materials; furniture; pallets and other forms of
containers and crating; posts and poles; and a wide-range of consumer goods. This wide array of products
generates waste wood when these products are disposed at the end of their useful lives. This waste wood
is typically included in the categories of Municipal Solid Waste (MSW) and Construction & Demolition
(C&D) wood, with the total amount generated in 2010 estimated at 70.62 million short tons; this amount
is difficult to track and may be understated.
•Some green building rating systems provide
conversion factors to estimate the weight
of construction waste if exact material
weights are not available.
•Calculate construction waste, by weight
or by volume, but be consistent throughout.
percentage of diverted construction waste =
amount diverted through recycling and salvage
Since wood is a significant portion of both MSW and C&D waste streams, and since wood can
be reused for a host of products (e.g., energy, fiber, or chemical-based), its recovery presents a
significant opportunity. Also, since most MSW and C&D waste streams are located near population
centers, the opportunity for creating useful consumer products is high (pool of natural resources near
markets).
Sources: Dovetail Partners, Inc. ”Municipal Solid Waste (MSW) and Construction and Demolition (C&D) Wood Waste Generation and
Recovery in the United States”, September 22, 2014, http://www.dovetailinc.org/report_pdfs/2014/dovetailwoodrecovery0914.pdf
total waste generated by the construction project
Getting to Zero Waste
Design: make design adjustments early, based on
Achieving zero construction waste depends
on designing products and industrial processes
so their components can be dismantled, repaired,
and/or recycled. The goal is to promote prefabrication, “right-sizing” of components, and the
closing of the loop of the product life cycle. Zero
waste means linking communities, businesses, and
industries so the waste of one becomes another’s
feedstock. It means preventing pollution at its
source. It means new local jobs in communities
across the country. The role of wood as a product
and as a feedstock for other processes is integral in
the quest to reach zero waste.
input from the contractor and other consultants,
to minimize waste generation during construction.
Consider standard product sizes, and application
and installation processes and the waste they
may generate.
Design: research the range of available waste
management options and identify large-volume
recyclables early in the design process.
Contract Documentation: determine which
materials will be source separated on site and which
(if any) will be collected in commingled bins.
Tender: ensure the general contractor understands
waste diversion tracking and documentation and
orients subcontractors to trade-specific responsibilities.
Construction: on a spreadsheet, tabulate diverted
Reusability and Recyclability of Wood Waste Depends
on the Quality and End Purpose of the Wood
•Demolished wood components are often not reusable or recyclable unless they are taken apart.
Check if the local recycling centres can handle nail removal.
construction waste, record the contact information of the
receiving facilities, and calculate diversion percentages.
•The use of wood waste as an alternate daily cover for landfills is not an acceptable means of waste
diversion under green rating systems.
Monitor: coordinate with the contractor at frequent
•While the use of used wood for firewood for wood-burning stoves and fireplaces is not a generally
acceptable means of waste diversion, burning clean wood waste to generate industrial process heat
and/or electricity is considered appropriate diversion methodology.
intervals during construction to ensure the project is on
track to achieve the waste management goals.
GREEN BUILDING RATING SYSTEM GUIDES
© 2014 |
Wood Specification:
Durability
Terminology
Building Durability Plan (BDP):
provides a framework within
which durability targets are
set and establishes criteria
for durability performance
of a building.
Design service life:
the period of time during which
a product is expected by its
designers to work within
its specified parameters.
Commissioning:
accomplishes higher energy
efficiency, environmental health,
and occupant safety; improves
indoor air quality by making
sure the building components
are working correctly and the
plans are implemented with
the greatest efficiency using
standard protocols and peer
review processes.
Durability is defined as the ability of a building or any of its components to perform the
required functions in a service environment over a period of time without unforeseen cost for
maintenance or repair.
Using durable materials, as well as appropriate building applications and design, minimizes
materials use. It also minimizes construction waste that would result from inappropriate material
selection or premature failure of the building and its constituent components and assemblies.
Using durable materials, while sometimes involving greater up-front costs, can result in
significant savings in terms of reduced-cost maintenance and repairs later in a building’s life.
Why a Durable High-performance Wood Building Envelope Adds Value
•Durable envelope design delivers the benefits of lower operation costs and a healthier building. Good design will
ensure that wood materials last and weather well in various climates and physical contexts. Strategies may include
minimizing contact of moisture with untreated wood, allowing for ventilation to both sides of untreated wood and
designing structures to shed water.
•Planning for maintenance, deconstruction, and adaptability can extend the life of building components and of the
building as a whole. Designing with wood allows for the use of easily demountable components and connections,
and for the use of fasteners that ease deconstruction, facilitate maintenance, and increase the potential future reuse
of building materials and components. In addition, the incorporation of easily accessible systems (such as removable
panels, etc.) reduces the need for extensive renovations or even replacement in the future.
•In general, as durability performance increases, so do the environmental merits of the project as a whole. A durable
assembly can dramatically reduce energy consumption because the elements providing thermal performance are
protected and maintain their functionality over the life of the building. Utilizing energy modeling software that
incorporates building envelope performance criteria such as insulative value and air tightness will help designers
to better understand the impacts of material choices—particularly the use of wood, in accomplishing an
energy-efficient, durable envelope.
•Indoor air quality can also be improved by using durable materials that have zero or low emissions and that prevent
moisture accumulation and mold or mildew growth.
•Durable materials and components that follow carefully considered design details can potentially remain useful in the
materials cycle for longer periods of time, thus reducing the need for new materials and the environmental costs of
resource extraction, production processes, and waste disposal.
Resources
Guideline on Durability in Buildings
CSA S478-95 (R2007) (available for
purchase from www.shopcsa.ca):
referenced by LEED, this guideline
provides a set of recommendations
to assist designers in creating durable
buildings.
ISO 15686-5:2008 – Buildings and
constructed assets – Service life
planning – Part 5: Life-cycle costing
(www.iso.org/iso/catalogue_
detail?csnumber=39843): life-cycle
costing enables comparative cost
assessments to be made over a
specific time, by taking into account
initial capital costs and future
operational costs. .
WoodWorks (www.woodworks.org/
Publications/informationSheets.
aspx): a primer on durability and
wood.
GREEN BUILDING RATING SYSTEM GUIDES
•Assessing life cycle costs based on design service life of the structure and the building envelope can be helpful in
evaluating alternative design approaches for the building.
•Some green building rating systems encourage high-performance and durable envelope design, either explicitly
through the development of a Building Durability Plan, or indirectly by setting goals for energy efficiency, thermal
comfort, and indoor air quality (all of which are facilitated through the design of the building envelope).
•With proper design and construction, wood-frame buildings resist damage from moisture, insects and other
organisms, and provide decades of service equivalent to other building types.
•Wood structures are adaptable and allow for design flexibility to meet changing needs. When they have been
designed properly with local climate impacts in mind, wood buildings can last centuries. Further, when part of a
well-planned regular maintenance program, wood products will last well beyond their planned service life. When it is
time to refurbish, wood products can be re-used and recycled.
How to Include Durability Considerations in Design
•Develop a Building Durability Plan at the
concept stage, and review the plan during
design for implementation during construction.
Components of particular relevance are major
structural elements (including foundations),
building cladding assemblies, roofing
assemblies, and those elements likely to have
significant impacts on the building’s operation
or performance (excluding mechanical and
electrical equipment).
•Early on, optimize the design of all components
of the building envelope by using energy
simulation and life cycle assessment tools
to analyze overall envelope performance.
•Make informed decisions about the
components of the building envelope
(i.e., based on life cycle performance).
•To minimize premature deterioration of walls,
roofs, and floors, select design strategies that
are appropriate to the geographic region.
•Reduce construction problems by specifying
realistic and achievable levels of workmanship
that are based on practical construction
methods and readily available technologies.
•Follow a building envelope commissioning
process to ensure performance and durability
standards are correctly established at
the outset and followed through during
construction and operation.
Wood Specification: Durability
What to Ask Suppliers
•It is important to get information about what the
expected service life of the building envelope
products will be in the context of the building’s
assembled condition.
•Ensure that the scope and limitations of product
warranties are fully understood.
•Enquire about care and maintenance solutions
for proposed materials and convey this information
to the building operator.
The Building Durability Plan
A Building Durability Plan (BDP) requires the design
professional (usually a building envelope consultant)
to agree to the following points:
•The building is designed and constructed with the
intent that the predicted service life will equal or
exceed the design service life.
•Where the service life of a component or assembly
design is shorter than that of the building, those
components or assemblies are designed and
constructed to be readily replaced.
•The service life is predicted by documenting
demonstrated effectiveness, by modeling of
the deterioration process, or by testing.
•A quality management program is developed
and documented.
•Quality assurance activities need to be carried out
to verify that the predicted service life is achieved.
•The building envelope construction is in general
conformance with the design details, and is
co-signed by the building science professional
and the general contractor.
•The BDP is endorsed, implemented, and signed
by the building owner.
Procedure
Step-by step approach to incorporating durability
considerations into the design:
Pre-design: determine durability goals by establishing
performance targets for the design service life of the
structure and building envelope (50 years is standard).
Design: create a BDP; review the details with the design
team, owner, and builder; update the Plan at milestones
throughout the project.
Contract documentation: confirm that the BDP is
developed and signed by a building science professional,
and that it is endorsed, implemented, and signed by the
building owner.
Wood Innovation and Design Center
Architect: Michael Green Architecture
Photo credit: Ema Peter Photography
Contemporary Wood Buildings in North America
The Wood Innovation and Design Centre (WIDC) in downtown Prince George, B.C. was completed in
October 2014. The six-story plus mechanical penthouse, 29.5 metre-high structure showcases British
Columbia’s growing expertise in the design and construction of large-scale wood buildings.
With the staggered floor slab design, the distribution of mechanical and electrical systems throughout
the building is resolved in a new and repeatable way. Horizontal chases are created between the
staggered timber slabs in order to run services both below the floor and above the ceiling. The service
chases inherent in the structural system offer extensive flexibility for reconfiguring the space for office
tenants. Therefore, the need for secondary ceiling finishes to conceal service runs is significantly
reduced. The wood structure is exposed at the ceiling, providing a beautiful finish that speaks to the
purpose and mission of the facility.
The structural concept used in WIDC is a “dry construction” design, virtually eliminating the use of
concrete above the foundation with the exception of the mechanical penthouse. This concept also
allows for the wood structure to be exposed as the ceiling finish. Dry systems also help with the endof-life story of the project. The building can be disassembled at the end of its functional life, and the
wood products can be reused.
Contract documentation: use a commissioning
procedure to confirm that the building envelope
construction is in general conformance with the design
details, and that is co-signed by the building science
professional and the general contractor.
Contract documentation: circulate copies of the
reports on the building envelope design review and the
building envelope field review, and of the BDP.
GREEN BUILDING RATING SYSTEM GUIDES
© 2014 |
Wood Specification:
Indoor Air Quality
(Low Emitting Materials)
Bare wood can be considered to be hypo-allergenic because it does not emit
toxic vapours. Solid wood products can be used in locations where occupants are
known to have environmental sensitivities. Increasingly, coatings, resins, and
binders used in wood products are available in low- or non-toxic formulations.
Why Indoor Air Quality Adds Value
Terminology
Indoor air quality:
the nature of air inside a building
that affects the health and
well-being of building occupants.
Quality is considered acceptable
when no known contaminants
exist at harmful concentrations
as determined by authorities, and
when a substantial majority (80%
or more) of the people exposed do
not express dissatisfaction with
it (American Society of Heating,
Refrigerating and Air-Conditioning
Engineers (ASHRAE) Standard
62.1-2007).
Volatile organic compounds (VOC):
carbon compounds that participate
in atmospheric photochemical
reactions (excluding carbon
monoxide, carbon dioxide,
carbonic acid, metallic carbides
and carbonates, and ammonium
carbonate). The compounds
vapourize at normal room
temperatures.
Contaminants:
unwanted airborne elements that
may reduce air quality (ASHRAE
Standard 62.1 – 2007).
Off-gassing:
the emission of volatile organic
compounds from synthetic and
natural products.
Globally Harmonized System of
Classification and Labelling of
Chemicals (GHS): :
defines and classifies the hazards
of chemical products, and
communicates health and safety
information on labels and safety
data sheets.
Urea formaldehyde:
a component of glues and
adhesives; a preservative in some
paints and coating products.
Commonly found in pressed
wood products such as hardwood,
wall paneling, particleboard, and
fibreboard.
GREEN BUILDING RATING SYSTEM GUIDES
•Despite the fact that solid wood is not a harmful material, it is frequently combined with products that
can adversely affect occupant well-being. It is therefore important to fully understand the toxicity of the
solvents, glues, sealants, flame retardants, resins, and preservatives used in and on some wood products.
•For example, urea formaldehyde (UF) is commonly found in resins associated with particleboard and
medium density fibreboard (MDF) production. Urea formaldehyde has been classified as a known
carcinogen by the World Health Organization. It also has a range of other health effects including
being a bronchial irritant and an asthma trigger.
•Indoor air quality certification standards exist for composite wood products (e.g., flooring, cabinetry,
panels) to verify that the products meet strict emission limits. These certification standards include
GreenGuard® and Floorscore®.
How to Include Low-emitting Materials in Design
•During the preliminary design stage, research
non-toxic alternatives such as composite wood
products that contain no added urea
formaldehyde.
•For most green building rating systems,
all composite wood products—including
particleboard, MDF, plywood, wheat board,
strawboard, panel, substrates, and door cores,
and associated laminate adhesives—should
contain no added urea formaldehyde resins.
•Identify target emission limits for products and
stipulate performance standards in the project
specifications (ideally, within the specific section
applicable to a particular trade or supplier).
•Consider making the submission of indoor air
quality compliance documentation a condition
of product approval.
•Indicate what must be provided in the way
of cut sheets, material safety data sheets,
certificates, and test reports.
Resources
Environmental Choice EcoLogo Program
(www.industries.ul.com/environment/ ):
presents a listing of products and services
that are EcoLogo certified and meet the
applicable environmental standards;
certified products are generally low in or
have no VOCs.
Green Seal (www.greenseal.org ):
database of certified products and services;
certified products are generally low in or
have no VOCs.
South Coast Air Quality Management
District (www.aqmd.gov ): source-specific
standards to reduce air quality impacts that
are referenced by most rating systems.
•Products such as plywood and oriented
strand board (OSB) use the red/blackcoloured phenol-formaldehyde resin. While
formaldehyde is still present in this type
of resin, there are almost no emissions
compared to those containing urea
formaldehyde.
•Strive to eliminate the use of toxic materials
altogether through alternative installation
strategies, such as using mechanical fasteners
for flooring and paneling in lieu of glues (which
also aids in future disassembly).
•Stress the importance of meeting indoor
air quality requirements during tender and
again when the contract is awarded. Include
requirements in subcontracts and
purchase orders.
•Communicate indoor air quality goals
to the construction team to ensure
successful implementation.
FloorScore™ Program, Resilient Floor
Covering Institute (www.rfci.com/ ):
a program that certifies flooring products
including wood flooring, developed
together with Scientific Certification
Systems.
GREENGUARD Indoor Air Quality
Certification Program
(www.greenguard.org/en/
CertificationPrograms/
CertificationPrograms_indoorAirQuality.
aspx ): indoor air quality certification
standards for low-emitting materials.
Wood Specification: Indoor Air Quality (Low-emitting Materials)
What to Ask Suppliers
•Early on in the planning phase, ask about the
production of materials and obtain the relevant
material safety data sheets describing the volatile
organic compound and urea formaldehyde
emissions of products.
•Make sure suppliers provide manufacturer contact
information so companies can be contacted for
additional information.
•If in doubt, request independently audited data
from a reputable third-party agency such as the
South Coast Air Quality Management District
in southern California (www.aqmd.gov).
Examples of Volatile Organic
Compound (VOC) Emission
Limits Relevant to Wood
Products
Formaldehyde Regulations and Structural Wood Products
Structural wood products such as plywood and oriented strand board (OSB) are manufactured to meet
stringent product standards, including Voluntary Product Standard PS 1-07 for Structural Plywood and
Voluntary Product Standard PS 2, Performance Standard for Wood-Based Structural-Use Panels. Because
wood products produced under these standards are designed for construction applications governed
by building codes, they are manufactured only with moisture-resistant adhesives that meet Exterior or
Exposure 1 bond classifications. These adhesives, phenol formaldehyde and diphenylmethane diisocyanate
(MDI), are chemically reacted into stable bonds during pressing. The final products have such low
formaldehyde emission levels that they easily meet or are exempt from the world’s leading formaldehyde
emission standards and regulations.
Adhesives: architectural
applications
Volatile organic
compound limit
(g/L)
Wood flooring adhesive
100
Subfloor adhesive
50
Contact adhesive
80
Structural wood member
adhesive
140
Drywall and panel adhesives
50
Multi-purpose construction
adhesives
Procedure
70
Top and trim adhesive
250
For most rating systems, low-emitting materials
credits function on a pass or fail basis. Best
practices in tracking indoor air quality hinge upon
the maintenance of a list of each indoor product
used on a project. Include the manufacturer’s
name, product name, and specific VOC data
(g/L, less water) for each product, as well as the
corresponding allowable VOC from
the referenced standard.
Substrate specific
applications
Wood
30
Architectural coatings
Clear wood finishes:
• Varnish
350
• Sanding sealers
350
• Lacquer
350
Flats
50
Stains
250
Wood preservatives
350
Source: South Coast Air Quality Management
District (southern California), Rule #1168 July 2005
and Rule #1113 January 2004
GREEN BUILDING RATING SYSTEM GUIDES
Source: /www.apawood.org/level_b.cfm?content=srv_env_form
All adhesives, sealants, paints, and coatings
used on the interior of the building (inboard
of the weatherproofing system and applied
on site) must comply with the applicable VOC
concentration limits and meet the certification
standards. Shop-applied products are exempt
from meeting the volatile organic compound limits.
A volatile organic compound budget procedure
allows for specialty applications for which there
is no low-VOC product option. It involves the
comparison of a baseline case with a design case.
The baseline application rate should not be greater
than that used in the design case.
Design: maintain a list of each of the following
wet products to be used
on site:
• Adhesives and aerosol adhesives
• Sealants and sealant primers
• Paints and coatings
Tender: obtain GHS or environmental information
sheets from all subcontractors prior to using the
products on site, with the product’s VOC data in
g/L. Check the referenced standard to ensure the
materials are in compliance.
Construction: if the materials are not in
compliance, return the relevant paperwork to the
subcontractors and request substitutions that meet
the referenced standard VOC limits. Non-complying
products are not allowed on site.
© 2014 |