In new buildings and those subject to alterations, the objective is
to optimise the use of fuel and power to minimise emission of
carbon dioxide and other burnt fuel gases into the atmosphere.
This applies principally to the installation of hot water, heating,
lighting, ventilation and air conditioning systems. Pipes, ducting,
storage vessels and other energy consuming plant should be
insulated to limit heat losses. The fabric or external envelope of a
building is constructed with regard to limiting heat losses through
the structure and to regulate solar gains.
Approved Document L2 of the Building Regulations is not
prescriptive. It sets out a series of objectives relating to
achievement of a satisfactory carbon emission standard. A number
of other technical references and approvals are cross referenced in
the Approved Document and these provide a significant degree of
design flexibility in achieving the objectives.
Energy efficiency of buildings other than dwellings is determined by
applying a series of procedures modelled on a notional building of
the same size and shape as the proposed building. The performance
standards used for the notional building are similar to the 2002
edition of Approved Document L2. Therefore the proposed or
actual building must be seen to be a significant improvement in
terms of reduced carbon emissions by calculation. Improvements
can be achieved in a number of ways, including the following:
- Limit the area or number of rooflights, windows and other openings.
- Improve the U-values of the external envelope. The limiting
values are shown on the next page. - Improve the airtightness of the building from the poorest
acceptable air permeability of 10 m^3 /hour/m^2 of external
envelope at 50 Pa pressure. - Improve the heating system efficiency by installing thermostatic
controls, zone controls, optimum time controls, etc. Fully
insulate pipes and equipment. - Use of high efficacy lighting fittings, automated controls, low
voltage equipment, etc. - Apply heat recovery systems to ventilation and air
conditioning systems. Insulate ducting. - Install a building energy management system to monitor and
regulate use of heating and air conditioning plant. - Limit overheating of the building with solar controls and
appropriate glazing systems. - Ensure that the quality of construction provides for continuity
of insulation in the external envelope. - Establish a commissioning and plant maintenance procedure.
Provide a log-book to document all repairs, replacements and
routine inspections.
Thermal Insulation, Buildings Other Than Dwellings---1