AD-L2 2010 Regulations - and Section 6, Scotland: 2010.

The latest amendment to the England and Wales Part L Regulations, and Section 6 Scotland, for the conservation of fuel and power (2010) came into effect on 1 October 2010. This is the second amendment following the introduction of these mandatory regulations in 2002.

The AD-L2: 2010 and Section 6 amendments are significantly changing the way non-domestic buildings - industrial, commercial, retail, leisure, schools and health - are assessed in terms of the energy consumed and the associated carbon dioxide emitted.

The 2010 amendments are the latest stage in the Government's planned progress to low-carbon buildings by 2019. There will be further reviews in 2013 and 2016.

2002 introduced prescriptive thermal performance values (U-values) and air tightness requirements for non-domestic buildings.

2006 completely changed the way buildings are assessed by comparing the energy performance of the whole building against a 2002 notional building of the same type. This included assessment of building services as well as the building fabric. Compliance was measured using the National Calculation Method (SBEM or equivalent). To comply buildings had to show an improvement of between 23 and 28% over the 2002 model building.

AD-L2: 2010 Detail changes

Prescriptive building types

Non-domestic buildings have been divided into eight main building types (Table 1). Each has been allocated a target energy/carbon emissions saving over 2006 levels that is considered achievable and that represents an average saving over all building types of 25%.

Table 1

Non-domestic building type	% new build
Shallow plan (heated only)	1
Shallow plan (Air conditioned)	1
Deep plan (Air conditioned)	40
Warehouse	33
Hotel	6
School	4
Retail	12
Supermarket	2

Notional Building Changes

The NCM tool (SBEM) further sub-divides each building type. A basic design format is prescribed for each building sub-type e.g SBEM assumes a given type of daylighting (side-lit windows, top-lit rooflights), hot water heating etc. It is vital that the correct type of building information is entered into SBEM, otherwise an incorrect computation could result in non-compliance.

Example – Industrial Buildings

Industrial type buildings are sub-divided into 4 principle categories (Table 2).

These can be found in the drop-down menu within SBEM or equivalent programmes. Designers should check against the NCM Handbook that the chosen notional building type has the same configuration as the design building particularly in terms of type of daylighting e.g. rooflights, side-lit windows and also type of building services.

Table 2

Type	Definition of building type
A1 / A2	Retail
B1	Offices and workshop businesses
B2 to B7	General industrial and special industrial groups
B8	Storage and distribution

The buildings are then further divided into zones, as with the previous SBEM, but new menus describe a choice of activities. The selection is different for each of the building types in Table 2.

Improved values in the Notional Buildings

In order to achieve the 25% improvement in energy/carbon emissions savings the set values in the Notional Building have been improved significantly compared to 2006, including:-

The level of improvement is so significant that in order to comply, all aspects of the building will have to be improved or made more efficient

U-values (Thermal performance of roofs, walls and floors)

Although the AD does not prescribe U-values, the fact that significantly improved levels have been set into SBEM means that adopting inferior U-values in the design specification could lead to non-compliance. If higher values are specified then additional major improvements will have to be made in the Building Services to achieve compliance.

Table 3 shows the U-values used in the Notional (non-domestic) buildings compared to 2006 levels, together with the new backstop values.

Table 3 - Fabric U-values and backstop levels

Notional building	2006	2010 Notional building balues	2010 New backstop balues
AD-L2A England & Wales
Roofs	0.25 W/m²K	0.18 W/m²K	0.25 W/m²K
Walls	0.35 W/m²K	0.26 W/m²K	0.35 W/m²K
Floors	0.25 W/m²K	0.22 W/m²K	0.25 W/m²K
Glazing	2.2 W/m²K	1.8 W/m²K	2.2 W/m²K
Rooflights	2.2 W/m²K	1.8 W/m²K	2.2 W/m²K
Rooflight (Max. area)	20% area	12% area	N/A
Section 6 Scotland			Maximum area weighted values(²)
Roofs (Scotland) (pitched) (flat)(¹)		0.16 W/m²K 0.25 W/m²K	0.20 W/m²K
Walls (Scotland)		0.30 W/m²K	0.27 W/m²K
(1) 'Flat' is defined as 'flat or roofs with integral insulation' including Insulated Panels (2) Maximum area weighted average values for all elements of the same type (see clause 6.2.1)

Air permeability

IIn AD-L2: 2010 for non-domestic buildings the target level has been lowered to 5 m³/(h.m²) at 50Pa with a backstop level of 10 m³/(h.m²) at 50Pa. The 10 m³/(h.m²) limit is a mandatory requirement for all new buildings except those below 500m2 for which 15 m³/(h.m²) can be adopted without testing. In Scotland, air permeability is expressed as a ‘recommended limit’ of 10 m³/(h.m²) - the same value as that used in SBEM for Scotland. Testing became mandatory for warrants made after 1 May 2011.

IMPORTANT NOTE on Air Permeability

Buildings below 4000m² footprint.
Research into levels of actual airtightness achieved for buildings with a footprint area under 4000 m² indicate that improvements from 10 to 5 m³/(h.m²) at 50Pa are difficult to achieve unless specific attention is paid to the detailing at both the design and construction stages. Insulated Panel manufacturers should be contacted to discuss suitable details and procedures. In buildings other than the simplest shed it may be prudent to use a design value for air permeability level between 5 and 10 m³/(h.m²) at 50Pa to avoid possible complications with compliance.

Buildings above 4000m² footprint.
In general terms as a building increases in size and volume it will be easier to achieve a low air infiltration value. However, the more complex buildings such as those with a large level of interface details, for example, offices, schools, hospitals and hotels need careful consideration as to whether an air permeability design value of 5 m³/(h.m²) at 50Pa is appropriate. Using a higher air permeability design value would lower the risk of failing the final SBEM calculation.

For larger, less complex buildings it may be possible to use an air permeability design value of less than 5 m³/(h.m²) at 50Pa however the risk of failing the final SBEM calculation and subsequent cost and program issues needs to be considered.

It is worthwhile remembering that buildings which beat the target carbon emission rate will achieve a better EPC rating and, if BREEAM assessed, will gain additional credits in the energy section.

Construction details

AD-L2: 2010 refers to Accredited Construction Details for non-domestic buildings. Whereas a scheme exists for domestic buildings, no scheme exists for non-domestic buildings and companies involved in that sector have advised the Government Regulations department (CLG) that a similar scheme to the domestic one would be both impractical and economically unfeasible.

EPIC and MCRMA (Metal roofing and Manufacturers Association) prepared Technical Paper 17 (see link below) for the 2006 AD-L Regulations. TP17 lists all the basic details and their psi-values that have been calculated by third parties using finite element analysis. All EPIC members have a full set of details for their Insulated panels calculated by the same method and should be contacted directly for further information.

The SBEM method requires Accredited Construction Details to be entered in the calculation tool. As this is not possible for the foreseeable future designers can enter the manufacturers own ‘certified accredited details’ and these will be accepted by SBEM with a 25% penalty on the psi-value. If other non-certified details are used then the penalty rises to 50%.

In almost all cases a 25% penalty makes very little difference to achieving compliance.

Lighting and building services

The targets, required efficiency levels and especially control procedures have been substantially tightened in the 2010 AD. Designers should contact a lighting or building services specialist to confirm the latest improved levels.

Refurbishment and shell fit out

The EPIC Guide contains the latest requirements in England and Wales, and Scotland for work relating to replacement and renovation. extensions and consequential improvements. in addition there are new requirements for shell and fit out work.

EPCs (Energy performance certificates) and DECs (Display Energy Certificates)

EPCs are required for all buildings and are calculated using SBEM or equivalent calculation methods.

It is important to ensure that the correct inputs into SBEM (or alternative approved software) are chosen – see above – so that the EPC record is relevant and accurate.

In addition to an EPC public buildings also require a DEC to be displayed in a prominent position near the entry point. DECs require that energy audits be conducted annually during the life of a building. This will naturally put a focus on the building energy use and identify how carbon emissions can be improved.

The benefit of insulated panels - whole life performance

The new Regulations, in line with the Energy Performance of Buildings Directive (EPBD), require that buildings perform as designed. The whole purpose of both the EPBD and the new Regulations is to encourage the conservation of energy and thereby control environmental emissions from the building. It is essential therefore, that the building in terms of its fabric and services works at a high level of efficiency, not only meeting these requirements on day one, but over the life of the building.

Insulated panels are a major contributor to achieving this objective and enable the designer to retain control of the building and the building services by offering a guaranteed performance and high level of security. Panels not only ensure a building fabric of excellent and controlled thermal performance but, together with a range of approved details, a level of air tightness that exceeds the regulatory requirements. Having absolute surety of these main characteristics means that the building HVAC services can be designed to work at maximum efficiency. Control of services that are major users of energy and are the primary source of emissions means easier compliance with AD-L2 (2010).

One of the key characteristics of insulated panels is the build quality. Panels are a one-piece component that are subject to factory controls and constant checks, thereby ensuring that quality is built-in and can be guaranteed. The metal facings in combination with the closed cell nature of the insulation component mean that the designed properties are retained for the life of the product. The highly engineered panel-to-panel joint detail also helps to ensure the quality of the system on site.

Building energy costs

Although the main focus will be how to achieve compliance in meeting the requirements of AD-L2 (2010) for both new build and refurbishment, the continuing rise in the cost of energy has placed renewed emphasis on the thermal performance of building envelopes.
 
Numerous studies over the past 20+ years have shown the substantial benefits that can be achieved in heating energy costs by moving to an insulated panel clad building. In certain cases payback periods as low as 18 months have been achieved for the re-cladding of buildings.

Footnote:
EPIC has been a leading member of the Working Group advising ODPM on the development of AD-L2:2010 as it affects lightweight industrial framed buildings and the use of metal cladding systems.
 
EPIC has been a leading member of the advisory committee working with BRE on the development of the calculation methodology and has been involved in all the trials of the SBEM programme.
 
EPIC together with MCRMA (Metal Roofing and Cladding Manufacturers Association) has prepared Technical Paper TP17 (see link below) as a 2nd tier guidance document on metal roofing cladding systems that is integral to the new regional Regulations. This document gives guidance on the calculation methodology, thermal performance, approved detailing and associated transmittance values and air tightness of buildings and aspects relating to compliance.
 
EPIC is a leading authority on building envelope issues for the important industrial, retail, distribution and leisure sectors of the construction industry.
 
EPIC will continue to stay well informed about developments in the industry, and will make that information publicly available.

References:
Approved Document L2A: Conservation of Fuel and Power
(New Buildings Other Than Dwellings) (2006 Edition)

Download:
MCRMA/EPIC Guide – Technical Paper TP17

Links:
Department for Communities and Local Government (DCLG)
AD-L2A 2010
AD-L2A 2006
AD-L2B 2006
SBEM

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