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Approved document L2 of the Building Regulations places requirements for energy conservation upon non-domestic buildings


  • Approved Document L2a Conservation of Fuel & Power in New Buildings Other Than Dwellings
  • Approved Document L2b Conservation of Fuel & Power in Existing Buildings Other Than Dwellings

These documents give detail on Government requirements in England and Wales for compliance with the Building Regulations, a further secondary document, the Non-Domestic Building Services Compliance Guide, gives detailed guidance for services including specific efficiency requirements for space and water heating. For Scottish Building Regulations the Technical Handbook, Section 6, gives detailed guidance. [Ireland?]

Government consulted upon changes to the content and structure of the approved documents in 2020. At this point the final outcome of the consultation is outstanding but is intended to be implemented in 2022. Proposed changes include combining ADL2a&b into a single volume together with the essential parts of the Building Services Compliance Guide, thereby streamlining the content and number of documents.

In order to gain planning consent for new buildings it is essential that an emissions compliance calculation is carried out using SBEM (Simplified Building Energy Model) or DSM (Dynamic Simulation Modelling). To comply the BER (Building Emission Rating) must be equal to or less than the TER (Target Emission Rating), with BER taking into account all regulated carbon emissions including space and water heating. A further expected change, to be confirmed, is the addition of a primary energy compliance metric for new buildings in addition to the exiting carbon metric.

Given the relatively challenging overall building compliance targets set in the current 2013 Part L the seasonal efficiency of boilers is a key specification figure which can have a marked impact on the overall BER.

In the case of retrofit and replacement projects the targets for compliance are lower than those in new build, however, boiler efficiency has a part to play here as Display Energy Certificates (DEC’s) for public buildings and Energy Performance Certificates (EPC’s) for all buildings can be improved by using more efficient plant.

Find out more about Part L.

Find out more about the Scottish Building Standards Non-Domestic Technical Handbook: