Download 2014 BS_1 AE Works

February 18, 2014
BUILDING SYSTEMS
(PART ONE OF TWO)
Presented by AIA-Pittsburgh’s Young Architects’ Forum (YAF)
and
Exam resources are available at AIA-PGH YAF ARE Review
http://yafpghare.wordpress.com/
Agenda
 5:30
 5:45
 6:00
 6:45
 7:00
 7:45
Introduction / Division Overview
Graphic Vignette Review
Multiple Choice Content Review … Electrical
Break (if desired)
Multiple Choice Content Review … Lighting
Questions?
Division Statement
Evaluate, select, and integrate mechanical,
electrical, and
specialty systems in building design and construction.
Exam Structure
 95 Multiple-Choice Questions (2 hours)
 Break (15 minutes)
 1 Graphic Vignette (1 hour)
 Mechanical and Electrical Plan
Test Day…
 Introductory Tutorial
 Multiple-Choice Questions
 Scheduled (Mandatory) Break
 Introductory Tutorial
 Graphic Vignette
 Exit Questionnaire
 TOTAL APPOINTMENT TIME
0:15
2:00
0:15
0:15
1:00
0:15
4:00
Suggested Sequence
 Construction Documents and Services
 Programming Planning and Practice
 Site Planning and Design
 Structural Systems
 Building Systems
 Building Design and Construction Systems
 Schematic Design
Content Areas

CODES & REGULATIONS (5-8% of scored items)


“…building codes, specialty codes, zoning, and other regulatory requirements…”
ENVIRONMENTAL ISSUES (10-15% of scored items)


PLUMBING (10-15% of scored items)





Principles
Materials and Technology
LIGHTING (18-23% of scored items)



Principles
Materials and Technology
ELECTRICAL (10-15% of scored items)


Principles
Materials and Technology
HVAC (18-23% of scored items)


“…sustainable design principles…”
Principles
Materials and Technology
SPECIALTIES (14-19% of scored items)


Principles
Materials and Technology
By the numbers…
 95 questions…
 2 hour testing time…
…1 minute, 15 seconds per question
 By content areas…
Codes/ Regulations….…………..……………..…4 - 8 questions
Environmental Issues..……………..……..…..10 - 15 questions
Plumbing……………………………………….....10 - 15 questions
HVAC…………………….…………………….……17 – 22 questions
Electrical ……………………………………….....10 - 15 questions
Lighting..……………….…………………….……17 – 22 questions
Specialties………………………………………...13 – 18 questions
GRAPHIC VIGNETTE
MECHANICAL & ELECTRICAL PLAN
Develop a reflected ceiling plan that
integrates ceiling, lighting, mechanical, and
structural systems
and incorporates life safety considerations.
PROGRAM
A reflected ceiling plan for an architect’s office is to be prepared. The space is in
a multistory building and is enclosed by leasable office space on one side, a
corridor on another, and two exterior walls. The client wants flexibility for
furniture placement, efficient lighting levels, and a comfortable environment.
The Work Screen
Mechanical and Electrical Layout
The Problem
Complete the partially completed reflected ceiling plan on the work screen
by:
(1) providing a grid for acoustical tile,
(2) locating lighting fixtures to achieve specified light intensity,
and
(3) developing a schematic HVAC plan complete with fire
dampers and air diffusers, ductwork, and return-air grilles to meet
specified air distribution requirements.
It is recommended that the ceiling layout be completed before ducts are
added. Your solution must be contained within the perimeter walls of the
overall space.
The completed plan should reflect effective coordination and integration of
structural, mechanical, and electrical units within the ceiling grid and should
provide for maximum flexibility for furniture layouts at the most economical
cost.
Program Requirements
Comply with the following requirements to develop the reflected ceiling plan:
Suspended Ceiling System
1. Provide a 2 ft X 4 ft grid with lay-in acoustical tiles in all spaces.
2. All ceiling heights are 9 ft above the finished floor.
3. Typical walls terminate 6 inches above the finished ceiling; bearing walls and fire-rated walls extend to
the bottom of the floor deck above.
Lighting System -- should be efficient and should minimize overlighting and underlighting.
1. For all spaces, use only recessed fluorescent fixtures to provide uniform light distribution with a light
level of approximately 50 footcandles measured at desk level (3 ft above the finished
floor).
2. In addition to the fluorescent fixtures required above, provide recessed accent light fixtures.

Locate the accent light fixtures along the west wall of the Architect’s Office so that the direct light
level on the wall at a height of 5 ft above the floor is 80 footcandles.

Space the accent light fixtures so that the light level between the fixtures at 5 ft above the
floor is 80 footcandles.

The accent light fixtures should not be considered in determining the uniform light distribution
levels.

The recessed fluorescent fixtures should not be considered in determining the accent light levels.
Program Requirements, cont.
HVAC System
The space is served by the supply and return risers within the shaft indicated on the floor plan. The HVAC
system should provide for uniform air distribution with an economical duct layout conforming to the
following restrictions:
1. Provide a minimum of one supply diffuser and one return-air grille in each space. An
acceptable air distribution pattern includes one supply diffuser and one return-air grille for every 144
ft of floor area (or portion thereof ) in each space.
2. Connect each supply diffuser to the rigid supply duct system with flexible duct. Do not
exceed 10 ft for flexible duct lengths.
3. Return-air grilles are open to the ceiling space, which serves as a return-air plenum.
Connect the plenum to the return riser with rigid duct.
4. Protect duct openings in fire-rated walls with fire dampers.
5. Flexible ducts fit through joist webs.
6. Rigid ducts fit under beams, in spaces between joists, and in a zone that extends 2 ft on either side of
Rigid ducts do not fit through joists or
between the bottom of joists and the ceiling.
beams and bearing walls in plan view.
Program Requirements, cont
Mechanical & Electrical Layout
Sample PASSING Solution
Mechanical & Electrical Layout
Sample FAILING Solution
General Tips…
Clear your head.
Remember – it’s not AutoCAD…
… or design studio.
Practice makes perfect…
… but don’t over-practice!!
Take your time.
Follow all of the instructions!!
Don’t second-guess yourself.
GRAPHIC VIGNETTE
Everybody read this!
If you have 2' between the long sides of 2x4s, you're doing it wrong.
If you're using circles for anything but accents, you're wasting your time.
GRAPHIC VIGNETTE
Frequently Asked Questions:
Q. Does it matter which way the damper points?
A. This appears to be a minor issue at most. The long leg of the symbol must be parallel to the wall…either in the center of the
wall or at the face of the wall.
Q. How do I center the grid precisely?
A. You don’t. Just get it as close as you can. The snap setting will not permit exact centering.
Q. What if I have ceiling tile slivers?
A. Doesn't matter. This is a ME vignette, not a pretty ceiling tile vignette. Center the lights.
Q. What is the ideal distance from the wall for lights?
A. That depends on the type of light and the lighting chart that goes with it.
Q. Can ducts be placed above lights?
A. Yes. Duct sizes and the plenum depth are not specified. If it mattered, NCARB would have to say so.
Q. I can’t get the lights to fit the room to provide the ideal requirement. Should I over or under light the room?
A. Decide which based on the use of the room.
Q. What is the ideal distance between supply diffusers and return grilles?
A. A minimum of 4’ is recommended, but the farther apart the better.
Q. Should supply diffusers be placed on the window side of the room?
A. There is no evidence that this matters to NCARB.
GRAPHIC VIGNETTE
Frequently Asked Questions: (continued)
Q. Can a flex duct supply more than one diffuser?
A. No. This is clearly defined in the program.
Q. The program specifies 1 set per 144 s.f. or portion thereof. If a room has 145 s.f., should I place one or two sets of
supply/return? Do I just round up or down?
A. 2 sets should be provided as a strict interpretation of the requirement but…the 3.1 sample passing solution had a room at 145
s.f. with only one set. The program also said to be efficient. An additional set for 1 s.f. is not efficient. Catch 22. If you are over the
required area, add the extra set to be safe.
Q. How many accent lights do I need?
A. That depends on the lighting chart. Determine how far from the light you can get the required lighting level. Draw sketch
circles that size. Place them along the appropriate wall so that their intersections occur at the face of the wall. Then place the
accent lights at the center of each circle. The goal is to cover as much of the wall as possible. Note if you change the distance
between the lights, you change the distance from the wall as well because the intersection point of the sketch circles will
change.
GRAPHIC VIGNETTE
Common Mistakes:
1. Inadequate separation between supply & return. Should be at least 4ft apart.
2. Return grilles not supported on 3 sides by the grid. They’ll fall out. Do not assume the software is smart enough to place
grid on the 4th side of a 2x2 light.
3. Incorrect light spacing. Read the lighting charts carefully. The current NCARB passing solution (2009) shows incorrect light
spacing in the Architect’s Office.
4. Connect the flex duct to the center of diffusers, not the edge.
5. Grid overlapping ceiling elements.
6. Rigid duct crossing joists when not within 2’ of a beam or bearing wall.
7. More than one rigid duct for each riser. Adding an extra damper wastes money.
Accent Lights:
GRAPHIC VIGNETTE
Strategy (checklist):
Read program carefully. Jot down pertinent notes.
•Draw grid in first room.
•Draw lighting fixture at ideal intervals. Do not worry about centering yet, just get the distances correct. For example, if
your lights are to be 4’ apart just start 2’ off the wall and place the fixtures at 4’ intervals. Stop when you are 4’ or less from
the wall. Lights shall be no closer than 1’ from the wall and no further than 4’ from wall. Ideally, lights should be 3’ from
walls due to bounced light from fixture combining with direct light on work surface at perimeter of room to meet desired
illumination levels. (Assuming a 2’ spread of light).
•Use the “move group” tool and shift the grid and lights so that they are centered on the room. If the layout does not appear
acceptable, move the grid off to the side and either rotate it and try again or if another fixture is available to use try placing
them in the same manner as above.
•Continue for all rooms. Verify that spaces with different fixtures have the correct fixtures, and if rooms are NOT to have the
grid then a grid is not provided. A grid can still be used to layout these spaces if the module is a 2 or 4’ module but make
sure you delete it afterwards. If the spacing is other than a multiple of 2’ then draw sketch circles and place them side by
side filling the room. Then place the fixtures in the center of the circles.
•Click on the grid in the first room and read the square footage on the screen below. Determine the number of diffusers and
returns based upon the program requirements.
•Spread diffusers out for optimum air flow. Do not place in front of door or against walls. In front of windows is a good
location.
•Place returns at least 4’ away from diffusers at opposite sides of room. Do not place return against wall.
•Support registers/diffusers on 3 sides.
•Repeat for all rooms.
GRAPHIC VIGNETTE
Strategy (checklist): continued
•Place fire dampers at supply and return risers. Short leg points in the direction of airflow.
•Draw short length of duct from center of return riser to outside edge of fire damper to plenum air space.
•Determine where rigid duct can be run perpendicular to joists and draw rigid duct out of riser and, following the program
rules, over to a point between two joists that is perpendicular to the center of a line drawn between the two outermost
diffusers to be connected to this run of duct. If necessary, branch a second run of rigid duct to pick up another string of
diffusers in the same manner.
•Draw duct portion perpendicular to joists in allowable area maintaining half the allowable distance from the
wall/beam/allowable zone. Ducts have a thickness and representative line indicates center of duct so if you draw your duct
the specified distance the duct will actually be out of the allowable zone.
•Draw rigid duct between joists to a point perpendicular to the furthest diffuser for that run of duct. Do not turn rigid duct
back towards risers, use additional branch of duct parallel to first branch if necessary to pick up more diffusers.
•Connect the diffuser to the rigid duct with flex duct no more than 10’, connected to the center of the diffuser. Flex duct
can run perpendicular to joists and can run on top of lights.
•Does this imply that rigid duct can not run over lights?
•Repeat for all diffusers for that branch of duct.
•Repeat with second branch of duct if necessary. Try to keep all diffusers from a room on the same main branch.
•If rigid return duct is called for, provide in the manner described for the supply duct.
•Verify all rooms are properly lit, adequately ventilated, and all ductwork is continuous.
Suggested Resources




“References Available During the Test” document
Mechanical and Electrical Equipment for Buildings
Heating, Cooling, Lighting (Lechner)
Dustin Goffron’s “Helpful Links for the ARE 4.0”

http://www.dustingoffron.com/ARE/
 Alkikat’s Study Guide
 Jenny’s Notes (AREndurance)
 www.arendurance.files.wordpress.com
 YouTube’s “WikiEngineering” channel
 MEEB’s Student Companion Site

http://bcs.wiley.com/hebcs/Books?action=contents&itemId=0471465917&bcsId=2879
 CED Engineering.com’s “Design Options for HVAC
Distribution Systems”

http://www.cedengineering.com/upload/Design%20Options%20for%20HVA
C%20Distribution%20Systems.pdf
Suggested Resources

ARE Building Systems Study Guide and Practice Exam (The Amber Book) By
Michael Ermann

Professor Norman Dorf’s ARE Solutions
Content Areas
Electrical
Lighting
Study Resources:Building Systems
Exam resources are available at AIA-PGH YAF ARE Review
http://yafpghare.wordpress.com/
Study Guides
NCARB Exam Guide
“References Available
During the Test”
Study Resources:Building Systems
Exam resources are available at AIA-PGH YAF ARE Review
http://yafpghare.wordpress.com/
Study Guides
Alkikat Building System Notes + Diagrams
Jenny’s AREndurance Study Guide
ArchiTangent’s ARE Prep: Building Systems
Study Resources:Building Systems
Exam resources are available at AIA-PGH YAF ARE Review
http://yafpghare.wordpress.com/
Jenny’s AREndurance Study Guide
DISCLAIMER
Content Areas
Electrical
Lighting
Electrical
Basic Electrical Physics
VOLTAGE ( V ):
measured in volts, the amount of force or potential in a circuit
CURRENT ( I ):
measured in amps, it’s the amount of flow through a circuit
RESISTANCE ( R ):
measured in ohms, the amount that slows down the current
Electrical
Basic Electrical Physics – Water Analogy
Water
Electricity
Potential
Height, pressure, or pressure
difference ( feet or psi )
Voltage V ( volts )
Current
Flow ( gallons per minute )
Current I ( amps )
Resistance
Resistance to Flow ( inches
per 100 ft. )
Resistance R ( ohms )
Electrical
Basic Electrical Physics – VOLTAGE ( V ) in volts
“ Water Pressure “
Electrical
Basic Electrical Physics – CURRENT ( I ) in amps
“ Water Flow“
Electrical
Basic Electrical Physics – RESISTANCE ( R ) in ohms
“ Resistance to Flow“
Electrical
Basic Electrical Physics – CIRCUIT
CURRENT
VOLTAGE
RESISTANCE
( battery )
( light bulb )
CURRENT
Electrical
Ohm’s Law
VOLTAGE ( V )
V=IxR
CURRENT ( I )
I =V / R
RESISTANCE ( R )
R =V / I
V and I are directly proportional to
each other > the greater the
voltage, the greater the current
I and R are inversely proportional to
each other > the greater the
resistance, the smaller the current
Electrical
Ohm’s Law Example
Given a 120 volt outlet and a hair dryer with a
resistance of 8 ohms, the current flow through
the hair dryer when it is turned on is _____ amps.
A. 15 amps
B. 6.7 amps
C. 1.5 amps
D. 0.67 amps
CURRENT ( I )
I =V / R
I = 120 v / 8 ohms
I = 15 amps
Electrical
Resistance
SERIES Resistance:
Resistors situated in one path
PARALLEL Resistance: Resistors situated in multiple paths
Electrical
Resistance
SERIES Resistance:
Resistors situated in one path
In a Series … Effective Total Resistance = Sum of All Resistances
R s = R1 + R2 + R3
Electrical
Resistance
PARALLEL Resistance: Resistors situated in multiple paths
In Parallel … Effective Total Resistance = Inverse of Sum of Inverse Resistances
1/Rp = 1/R1 + 1/R2 + 1/R3 OR Rp =
1
1/R1 + 1/R2 + 1/R3
Electrical
Resistance
Resistors situated in Series AND Parallel
Electrical
Transmission of Electricity
Direct Current ( DC )
Current flows in ONE direction, with constant voltage
Example: Batteries
DC Power Equation: Power ( watts ) = Voltage x Current
P = V x I
Example:
A 12 volt battery connected to a 4 ohm resistor … the current is ____ ?
I = V / R = 12 v / 4 Ω = 3 amps
P = V x I = 12 v x 3 amps = 36 watts
Electrical
Transmission of Electricity
Alternating Current ( AC )
Electricity has nearly zero inertia and therefore the direction
of flow can be reversed very rapidly by reversing the voltage.
Single-Phase
Three-Phase
Electrical
Transmission of Electricity
Single-Phase AC Power Equation
P = V x I x PF
( PF = Power Factor in decimal form )
Three-Phase AC Power Equation
P = V x I x PF x √ 3
( PF = Power Factor in decimal form )
Example:
A three-phase motor draws a current of 7 amps at 240 volts
and the power factor is 0.8… the power is ____ ?
P = V x I x PF x √ 3
=
240 v x 7 amps x 0.8 x 1.73
=
2,325 watts
Electrical
Equipment
Motor vs Generator
Motor > converts electrical energy into mechanical energy
Running a current through a wire loop creates a magnetic field.
This is the basic principle behind electric motors and solenoids.
Generator > converts mechanical energy into electrical energy
Rotating a wire loop between two magnetic poles will generate a
current. This is the basic principle behind generating electricity.
Electrical
Equipment
Motor Types
Four types in general use:
1. DC motor – small scale applications, elevators for
smooth continuous acceleration
2. Single phase AC motors – typically 3/4HP or less such
as exhaust fans, pumps, etc.
3. 3-phase induction motors – larger motors, constant
rpm such as air handlers, power factors from 0.7 to 0.9
4. Universal motors – DC or AC, variable speed, such as
hand drills, mixers, similar appliances
Electrical
Equipment
Transformer
Transformers > change the voltage of AC Circuit
Consist of an iron core on which two separate coils of wire are wound,
called the primary and a secondary “windings”
“Step-Up” Transformer
… changes to a higher voltage
“Step-Down” Transformer … changes to a lower voltage
Waste energy is HEAT, which must be dissipated.
Transformer sizes are defined in volt-amps ( VA ), or kilovolt-amps ( KVA )
Electrical
Equipment
Transformer Voltages
Typical commercial system voltages:
480Y/277V-3ph-4w and 208Y/120V-3ph-4w
Typical residential system voltage:
120/240V1ph-3w
Older buildings sometimes had two services:
120/240V-1ph-3w
240V-3ph-3w delta for motor loads
Electrical
Equipment
Transformer Voltages … Which One to Choose?
– What is available from the power company?
– What is the building square footage?
– Building use? (industrial, office, retail, warehouse, multi-tenant, high-rise)
– Standard distribution equipment sizes and how they affect architecture
(NEC workspace clearances, multiple doors to main electrical room, doors
with panic hardware opening outward from the room)
– What makes sense for the major equipment?
– Also … higher voltage = lower current = smaller wire
higher voltage = better tolerance for voltage drop
higher voltage = more load per circuit = fewer circuits used
Electrical
Equipment
Panelboards
Types: Fuse box, Circuit breaker panelboard, Frankenstein panel (old)
– Provides a central distribution point for branch circuit wiring
– Each breaker serves a single circuit
– Overcurrent protection is designed to protect the wiring to the load
– Power riser diagram includes all of the panelboards and their
interconnections (conduit and wire) all of the way to the service entrance
– NEC defines clearances required at panelboards
( 36” front clearance, 30” clear width, 72” headroom, etc. )
Electrical
Electrical Distribution
Riser Diagram Components
– Service entrance
– Main service disconnect
– Main switchboard
– Feeders
– Distribution boards
– Feeders
– Branch panelboards
– Branch circuits
Electrical
Electrical Distribution
Electrical
Example Question
Answer: D
Electrical
Components
Conduit
– Rigid – steel, safest, same wall thickness as Schedule 40 PVC,
connections are threaded, galvanized for exterior use.
– Intermediate Metallic Conduit (IMC) – steel, slightly thinner and less
expensive than rigid.
– Electrical Metallic Tubing (EMT) – thinnest of the simple metal conduits,
compression fittings, galvanized, called “thin wall”.
– Flexible Metallic Conduit – available with or without a waterproof (liquid
tight) jacket, called “flex” or “Greenfield”, can be used everywhere except
underground.
– Interlocked Armored Cable (BX) – factory assembled wires encased in an
interlocking spiral metal armor, (cannot add wires to it), cannot be used
underground or embedded in concrete.
Electrical
Components
Receptacles
– Also called an outlet. ( A plug is what you put into the outlet )
– All 120V outlets should be 3-prong where the third prong is the ground.
– In a large room, provide more than one circuit for the outlets.
– Receptacle placement in commercial buildings:
– show windows
– HVAC equipment outlets
– No “code” for convenience outlets
Electrical
Components
Receptacles in Residential
– NEC 210.52 has very specific rules on the placement of receptacles in
dwelling units and hotels.
– 12 feet on center on any wall space greater than 2 feet in width for the
following rooms:
kitchen, family room, dining room, living room, parlor,
library, den, sunroom, bedrooom, or similar
– At least one receptacle for hallways of 10 feet or more in length.
Electrical
Components
Receptacles in Residential
– One in each basement
– One for laundry
– One for garage
– One for each bathroom basin
– One at the front and back exterior of each dwelling unit
– One at each porch/balcony/deck
– Kitchen countertops and islands
Electrical
Components
Switching for Lighting
Switching can be done centrally via circuit breakers in a panel, or
locally via wall switches.
Switch types:
– One switch location: need (1) 2-way switch.
– Two switch locations: need (2) 3-way switches, one at each location.
– More than two switch locations need (2) 3-way switches at each
“end” location and a 4-way switch at every “in between” location.
Electrical
Components
Switching for Lighting
One switch location: need (1) 2-way switch
Electrical
Components
Switching for Lighting
Two switch locations: need (2) 3-way switches, one at each location
Electrical
Components
Switching for Lighting
More than two switch locations need (2) 3-way switches at each “end”
location and a 4-way switch at every “in between” location
Electrical
Components
Switching for Lighting … Alternate Names
SPST = 2-way
SPDT = 3-way
DPDT = 4-way
Electrical
Grounding
– Ground wire provides a low resistance path for current to the ground in
the event of a short circuit
– Ground wires are usually bare or covered with green insulation
– All ground wires are ultimately connected to a grounding electrode, such
as building steel, a metal water pipe, etc. per NEC Article 250
Electrical
Emergency Power
– Emergency power is required for emergency egress lighting and exit signs
– IBC Section 1006 covers Means of Egress lighting levels and power sources
– Hospitals have special emergency power requirements
– Stand-by power may be required for elevators
– Lighting backup power is often provided through emergency battery
ballasts that are continuously recharged while power is on, and operate one
or more lamps when normal power is lost
– Emergency lighting may be provided through individual emergency lighting
units that contain a rechargeable battery. These operate only when normal
power is lost
Electrical
Emergency Power Generators
– Generator fuel supply should be enough for two hours of runtime under load
– Common fuel supplies are diesel, natural gas, and propane
– Separate automatic transfer switches are provided for life safety, stand-by,
and optional equipment loads.
Electrical
Electrical Power Sources
– Natural Gas
– Gas / Oil Generators
– Coal Plants
– Hydroelectric
– Photovoltaic
– Wind
– Nuclear
Electrical
Example Question
Question:
An office which is occupied for 10 hours per day has a
typical load of 10,000 W. If the electrical rate is 6 cents
per kilowatt-hour, what do they pay in electric per day?
Answer:
10 hours / day x 10,000 W = 100,000 W-hrs / day
=
100 kW-hrs / day
100 KW-hrs / day x $0.06 / kW-hr
= $6 / day
Electrical
Example Question
Question:
Which conduit system is unacceptable for embedding in concrete?
A. Rigid Conduit
B. Flexible Metallic Conduit
C. Intermediate Metal Conduit (IMC)
D. Interlocked Armored Cable (BX)
Answer:
D. Interlocked Armored Cable (BX)
Electrical
Example Question
Question:
What is the minimum required clear distance from the
face of an electrical panel to the nearest obstruction?
A. 24 inches
B. 36 inches
C. 48 inches
D. 72 inches
Answer:
B. 36 inches
Electrical
Example Question
Question:
The flow of electricity is affected by all of the following EXCEPT?
A. potential
B. current
C. power
D. resistance
Answer:
C. power
I = V/R
Electrical
Example Question
Question:
In an overhead power district, the power company may provide service …
I. underground
II. overhead
III. underground if the owner provides the conduit between the
building and the power pole
IV. underground if the conduit is encased in concrete
A. II only
Answer:
C. II and III
B. I, II, III, and IV
C. II and III
D. III and IV
Electrical
Questions ? ?? ???
Electrical
Short Break . .. … Then Lighting . .. …
Content Areas
Electrical
Lighting
Lighting
Basic Concepts
What is Light?
• Light is defined as that part of the electromagnetic radiation spectrum that
can be perceived by the human eye
– Blue light (450 to 475 nanometers)
– Green and Yellow light (at 525nm and 575nm)
– Red light (at 650nm)
• White light is the combination of all wavelengths
Lighting
Basic Concepts
Definitions
• Transmitted: light that passes through a surface
...all other is reflected or absorbed
• Transparent: material that allows for an image to pass through ( glass )
• Refraction: material that changes an image while allowing it to pass
through ( lens )
• Translucent: material that allows light to pass through, but not an image
(frosted glass )
• Reflective: material that bounces a light off
Lighting
Basic Concepts
Definitions
• Specular Reflection: results from a smooth polished surface like a mirror.
The angle of incidence equals the angle of reflection
• Diffuse Reflection: results from a uniformly rough surface.
It appears uniformly and the image of the source cannot be seen
Lighting
Basic Concepts
Definitions
• Candlepower (CP): the measurement for the intensity of a source, and
approximately equal to the horizontal output from a single candle
• Lumen (I): SI unit of luminous flux, a measure of the total amount of visible
light omitted by a source. One lumen of luminous flux uniformly cast on 1
square foot of area creates an illuminate of 1 foot candle
• Illumination (E): the amount of light arriving at a surface
• Footcandle (FC): the calculated amount of illumination on a surface
• Luminance: the measurement of how bright light leaving an illuminated
surface is...it depends on reflectivity or transmittance.
• Illuminance: the density of luminous energy expressed as lumens per unit
area
Lighting
Basic Concepts
Definitions
• Coefficient of Utilization (CU): ratio between lumens reaching the working
plane in a specific space and the lumens. Typically provided by the
luminaire manufacturer, it’s an indication of the effectiveness of a luminaire
in delivering light in a given space
• Light Loss Factor (LLF): effect of temperature and voltage variations, dirt
accumulation on luminaries and room surfaces, lamp output depreciation,
maintenance conditions
• Efficacy: the amount of light produced vs. the power input (lumens/watt)
Lighting
Basic Concepts
Definitions
• Color Rendering Index (CRI): a measure of the effectiveness of a source to
make colors “right” to the viewer. The best possible rating is 100. 85 + is
good.
• Color Temperature (K): a characteristic of
visible light where its color reveals it temp.
Lighting
Basic Concepts
Equations
Lighting
Basic Concepts
Measuring Light
• Photometric readings are usually taken at the height of a "working plane"
because this approximates the height to typical visual tasks
• Typical fc levels
• Office:
30-50 fc
• Corridor:
10 fc
• Surgery Suite:
100-500 fc
• Emergency egress: 1 fc at floor
Lighting
Basic Concepts
Light vs Lamp vs Luminaire
• Lamp: a device for giving light (e.g. a light bulb)
• Luminaire: a complete light fixture, including lamp(s)
Lighting
Daylighting
Controlling Daylight
• Overhangs, fins, and other architectural shading devices.
• Sawtooth (not bubble) skylights allow glass to face north for illumination,
not south for solar heat gain.
• Interior window shading devices, which allow solar gain during cool
months, and the blocking of solar radiation during the warmer seasons.
• Light shelves, which permit the daylight to reflect off the ceiling and
penetrate farther into the interior without affecting views outside.
Lighting
Artificial Lighting
Types
• Incandescent
• Tungsten Halogen
• Fluorescent
• High Intensity Discharge (HID)
• LED (Light Emitting Diode)
Lighting
Artificial Lighting
Incandescent
• Tungsten alloy placed within a sealed bulb containing an inert gas
• Filament glows by passing an electric current through it
• Advantages:
• Inexpensive
• Compact
• Instant on
• Dimmable
• Typically “warmer color that sunlight or daylight, rich in yellows and
reds and weak in green and blues
• Disadvantages:
• Inefficient (produce heat)
• Short lamp life (~ 700 – 1,000 hrs)
Lighting
Artificial Lighting
Incandescent
Lighting
Artificial Lighting
Tungsten Halogen
• A variation of incandescent bulbs (under higher pressure and temperature)
• Smaller than standard incandescent bulbs
• Advantages:
• Longer life
• Low lumen deprecation of the life of the bulb
• More uniform light color
• Dimmable
• Whiter light than incandescent
• Instant on
• Disadvantages:
• Much hotter than incandescent bulbs
Lighting
Artificial Lighting
Tungsten Halogen
Lighting
Artificial Lighting
Fluorescent
• A glass tube holds a mixture of an inert gas and low pressure mercury vapor
• When lamp is energized, an arc of mercury is formed creating an ultraviolet
light that strikes the phosphor coated bulb
• Bulb fluoresces and produce a visible light
• Ballast: supplies the proper starting and operating voltages to the lamp and
limits the current
• Produces noise and heat
Lighting
Artificial Lighting
Fluorescent
• Advantages:
• High efficacy (About 80 lm/W)
• Low initial cost
• Long life (about 10,000 - 20,000 hours)
• Dimmable
• Variety of color temperatures (improving...no longer just “cool white”)
• For fluorescent lamps, dimming down to 40% of output is possible
without substantially reducing luminous efficacy
• Instant on with slight warm-up
• Disadvantages:
• More expensive than incandescent bulbs
Lighting
Artificial Lighting
Fluorescent
Lighting
Artificial Lighting
High Intensity Discharge (HID)
• A lamp within a lamp that runs at a very high voltage
• An electrical arc is struck across tungsten electrodes in a glass tube filled
with gas and metals
• Metals produce the light once they are heated to a point of evaporation
• Advantages:
• High efficacy (About 80 lm/W) • Great for High Spaces or Outdoor use
• Disadvantages:
• Produce light that is not flattering to human skin, so not used for
commercial / retail / residential applications
• Long Warm-up Time
Lighting
Artificial Lighting
High Intensity Discharge (HID)
Lighting
Artificial Lighting
LED (Light Emitting Diode)
• Solid State Lighting
• Bulbs without a filament, plasma, or gas
• Low in power consumption with a long life span
• Advantages:
• No UV rays
• Instant on
• Standard dimming
• Disadvantages:
• Cost ( this is improving … esp. when considering life costs)
Lighting
Systems
Indirect
• 90% - 100% of light output is directed to the ceiling & upper walls of a room
• Almost all of the light reaches the horizontal plane indirectly, it has to
bounce off something else first (so the ceiling & walls are basically the light
source)
• Suspend 12”-18” from the ceiling minimum
• Allows for uniform lighting, lacks shadows, low brightness, and is highly
diffuse
• Pretty inefficient system
• Typical Uses: Good for Offices, lounges, waiting areas
Lighting
Systems
Semi-Indirect
• 60% - 90% of light is directed upward, similar to indirect, but more efficient
• 10% - 40% of light is directed downward
• Direct and reflective glare is relatively low
• Kind of a monotonous system
• Typical Uses: Good for Offices, lounges, waiting rooms, corridors
Lighting
Systems
Diffuse / Direct-Indirect
• Equal distribution of light up and downwards
• Bright ceilings and upper walls
• All surfaces are lit
• Give light in all directions, and should be suspended 12” minimum from the
ceiling
• Efficient system
• Typical Uses: Good for classrooms, standard office work spaces,
merchandising areas
Lighting
Systems
Semi-Direct
• 60% - 90% of light is directed downward
• 10% - 40% of light is directed upward
• Shadowing should not be a problem
• A pleasant environment
• Inherently efficient
• Typical Uses: Offices, classrooms, shops, working areas
Lighting
Systems
Direct
• Essentially all light is directed downward
• Ceiling illumination comes from floor and furnishing reflection
• Requires a light, high reflectance, diffuse floor unless a dark ceiling is
desired
• Efficiency depends on if the distraction is spread or concentrating
• Gives little surface illumination, requiring the addition of perimeter lighting
• Downlights create sharp, theatrical atmosphere, not good for work spaces
• Can be gloomy and cave-like
• Typical Uses: General Lighting (spread) OR Highlights, local / supplemental
lighting, and privacy atmosphere lighting (concentrated)
Lighting
Systems
Lighting Control
• Any building over 5,000 square feet is required to have Lighting Controls
• Occupancy Sensors
• Relay Panels
• A properly designed lighting control system can reduce energy usage up to
60% over a simple on/off system
Lighting
Other Considerations
• Artificial Lighting consumes a significant part of all electrical energy
• 20 – 60% of energy used in residential / business is due to lighting
• Light Pollution
• Light Trespass – unwanted light on private property
• Can reduce light levels at perimeters, or use shielding devices to block
• Emergency Lighting:
• IBC, National Electric Code, Life Safety Code all have provision for
emergency lighting
• Required areas include:
Exit Stairs
Corridors
Assembly Spaces
Educational Facilities
Other high occupancy loads
• Minimum lighting level required is 1 foot-candle at the floor level
• Illuminated exit signs are required
Lighting
Example Question
Question:
Which of the following terms means “brightness” ?
A. Luminance
B. Illumination
C. Glare
D. Radiation
Answer:
A. Luminance
Illumination is the amount of light arriving at a surface (not leaving it)
Glare results from extreme contrasts in brightness
Radiation is a method of transfer of heat or other energy
Lighting
Example Question
Question:
The intensity of a light source is measure in what units?
A. Lumens
B. Candlepower
C. Footcandles
D. Lamberts
Answer:
B. Candlepower
The rate of flow of light is measured in Lumens
A footcandle is a unit of illumination equal to one lumen per square foot
A Lambert is a unit of luminance or brightness
Lighting
Questions ? ?? ???
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