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Part L
Structure - Part L 2006 comprises four parts
ADL1A
ADL1B
New dwellings
Work in existing dwellings
ADL2A
ADL2B
New buildings other than dwellings
Work in existing buildings other than dwellings
The four parts shall be used in conjunction with
ADF1
Means of ventilation
As well as extensive use of second-tier documents
Compliance
Compliance with ADL no longer by elemental method!
Individual building element can not comply with ADL!
Only the whole building can comply with ADL in terms of whole building CO2
emissions rate, in kg/(m2·annual).
The new ADL gives significant design flexibility – trading off is no longer limited
among different building elements. Trading off can be also been taken place
between building envelope and building service.
It also includes provisions to implement the Energy Performance of Buildings
Directive
Approach
The general approach of complying with ADL would be:


Client briefs architects;
Architects propose a building, carry out or commission a specialist to carry
out whole building CO2 emission rate according to National Calculation
Method (NCM), and make sure the proposed building has an CO2 emission
rate (BER) less than the target CO2 emission rate (TER), that is
BER < TER.

Architects specify
o
o

The fraction area and the g factor of the glazing, and
The U-values of different cladding zones, and the U-values of major
components if necessary.
Façade specialist contractors carry out the detailed designs to meet the
specification according to second-tier document ‘The thermal assessment of
window assemblies, curtain walling and non-traditional building envelopes’
published by CWCT.
This approach gives great design flexibility in choosing U-value of components.
National calculation method
BER and TER are calculated according to the national calculation method (NCM).
NCM calculates the annual energy use for a proposed building and comparing it with
the energy use of a comparable ‘notional’ building in terms of whole building CO2
emission rate. It takes into account of:

Heat loss due to temperature difference between the internal and external
environments;
Solar heating and shading;
Heat lose due to mass migration (air leakage and moisture transfer);
Day lighting;
Artificial lighting, hot water service, heating and cooling plant, ventilation, etc.




Both calculations for proposed and the ‘Notional’ building make use of standard sets
of data for different activity areas and call on common databases of construction and
service elements.
Notional building is the building with the same shape, geometry, and usage as the
proposed building that complies with ADL 2002, and with carbon emission rate
Cnotional.
Target carbon emission rate is calculated for the notional building taking into
account of energy improvement factor and the concession of using low and zero
carbon emission fuel.
TER = Cnotioal x (1 - improvement factor) x (1 - LZC benchmark)
ADL2A 2006 gives the energy improvement factor and the LZC benchmark for
different types of buildings as following:
Servicing strategy
Heat and naturally ventilated
(include buildings with low
levels of heating)
Heated and mechanically
ventilated
Air conditioned
Improvement
factor
LZC
benchmark
TER
15%
10%
0.765Cnotional
20%
10%
0.72 Cnotional
20%
10%
0.72 Cnotional
Calculation software
The whole building carbon emission rate shall be calculated using certified software.
The software enables you to test the proposed building for compliance with ADL
2006 by any of the two approved routes:

Simplified Building Energy Method

o iSEMB for non-dwelling buildings
o SAP 2005 for dwelling buildings
Approved calculation Methodology
o IES 'Virtual Environment' software, Version 5.5
o EDSL TAS Version 9.0.9
Schematic diagram of design procedure
Worst performance limit
ADL 2006 also set out limit for worst performance of building elements.
For new dwelling buildings:
Element
Area-weighted
dwelling average
Worst individual
element
Wall
0.35
0.7
Floor
0.25
0.7
Roof
0.25
0.35
Windows, roof windows &
rooflights
2.2
3.3
Doors
2.2
3.0
For existing dwelling buildings
Element
Extensions
Renovations
Wall
0.30
0.30
Floor
0.22
0.22
Roof
0.16 ceiling
0.20 on pitch
0.16 ceiling
0.20 on pitch
1.8
or
BFRC Band D
2.0
or
BFRC Band E
2.2
2.2
Wall
Area-weighted average
(W/m2K)
0.35
Individual element
(W/m2K)
0.70
Floor
0.25
0.70
Roof
0.25
0.35
Windows
2.2
3.3
Personnel doors
2.2
3.0
High usage doors
6.0
6.0
Vehicle access doors
1.5
4.0
Windows, roof windows &
rooflights
Glazed doors
For non-dwelling buildings
Element
Area allowance
In order to limit solar over heat, ADL 2006 also sets out the area allowance
Building type
Windows and doors Rooflights as a % of
as % of exposed wall
roof
area
Residential buildings
30
20
Places of assembly, offices and
shops
40
20
Industrial and storage buildings
15
20
Mandatory air leakage requirement
ADL 2006 requires that air leakage rate shall be no great than 10 m3/h/m2@50Pa.
The actual air leakage rate should not be greater than the testing result.
Whole building test shall be carried out by accredited testing organisations (currently
Taylor Woodrow Engineering and BISRIA).

The Building Regulations AD L2A 2006 requires that all buildings with gross
floor area greater than 500 m2 should be tested.

There is a Statue Law making it an offence for a Building Control Officer to
sign off a building without an air leakage test certificate.

Buildings with floor area less than 500 m2 should either:


Be tested to show that the air leakage rate assumed in the energy
modelling has been achieved
Modelled with a air leakage rate of 15 m3/(h·m2). (Clearly this is
disadvantageous as compensating measures have to be taken
elsewhere)
Limiting solar gain

Temperatures not to exceed 28 oC based on a July day

Notional building uses glass with total solar energy transmittance (g-value) of
0.65

Requires consideration of:
 Area of glass
 Orientation
 Glass type
 Shading devices