Approved Document L2A adopts the same approach to Approved Document L1A, taking the entire building’s performance and CO2 emissions into consideration. All new buildings other than dwellings must be designed and built with their Building CO2 Emissions Rate (BER) being no worse than the Target CO2 Emissions Rate (TER). The TER is set from a Notional Building of same size and shape to the actual building. There are three defined Notional Buildings; heated and cooled buildings (that are side lit or unlit), and toplit buildings. The specification for each building type is summarised in Section 5 of ADL2A. CO2 Emissions Rates for buildings other than dwellings are calculated using the Simplified Building Energy Model (SBEM).
Special considerations are made for low energy demand buildings, modular/portable buildings, temporary buildings, industrial sites, workshops, and non-residential agricultural buildings. ADL2A should be consulted for further details. If the building is built to match the Notional Building specification, its BER should meet the TER. Note that other factors need to be taken into consideration including continuous building fabric insulation, air permeability, thermal bridging, performance testing and limiting the effects of heat gains in summer.
Although ADL2A is for new buildings other than dwellings, there are some exceptions if a dwelling is featured within the new building. For more details on these exceptions ADL2A should be referred to.