Scottish Government

The aim of Section 6 (energy) of the Building Regulations is to ensure that effective measures for the conservation of fuel and power are incorporated in buildings. In addition to limiting energy demand through specification of the performance of building fabric and building services, a carbon dioxide emissions standard (standard 6.1) obliges designers of new buildings to consider building performance in an holistic manner.

UK calculation tools conform with European Directive 2002/91/EC and are to be used with the carbon dioxide emissions standard and in the production of Energy Performance Certificates (EPCs). For dwellings, calculation should be carried out using the UK Government's Standard Assessment Procedure for the Energy Rating of Dwellings (SAP). For non-domestic buildings, the National Calculation Method (NCM) should be used.

This page provides information on approved software and on use of such tools to meet requirements under standard 6.1 (carbon dioxide emissions) and standard 6.9 (energy performance certificates) within Section 6 (energy).

Approved Domestic Software

Carbon dioxide emissions and energy ratings for dwellings are calculated using the UK Government's Standard Assessment Procedure for the Energy Rating of Dwellings (SAP). The Building Research Establishment (BRE) lists SAP software approved for use in Scotland.

For information on current approved SAP 2009 software, as well as the updated SAP 2009 document and a link to the SAP conventions document, please visit the BRE SAP 2009 website. Information on previous SAP 2005, used to demonstrate compliance with standard 6.1 from 1 May 2007 until 30 September 2010 and to produce EPCs prior to 17 April 2011, is available on the BRE SAP 2005 website.

Approved Non-Domestic Software

The methodology for non-domestic buildings in the UK is the National Calculation Methodology (NCM). The procedure for demonstrating compliance with the building regulations for non-domestic buildings is by calculating the annual carbon dioxide emissions for the proposed building and comparing them with those of a 'notional' building which has the same size and shape. Both calculations use standard sets of data for different activity areas and call on common databases of construction and service elements. A similar process is used to produce an 'asset rating' in accordance with the EPBD. The NCM therefore comprises the underlying method and the standard data sets. The NCM allows the calculation to be carried out either by the SBEM (Simplified Building Energy Model) or by approved simulation software tools.

SBEM

SBEM has a basic user interface, iSBEM, which is a free tool. iSBEM is updated to reflect amendments in Section 6 of the Technical Handbooks or improvements to the tool functionality. The latest version which is suitable for use in Scotland is listed below and is available for download through the following link:

FI-SBEM and Dynamic Simulation Modelling (DSM)

There are also commercial front-end software tools that interface with the SBEM engine and calculate the building carbon dioxide and energy performance. Dynamic Simulation Modelling (DSM) primarily applies to building analysis software that can model the thermal dynamic response of buildings. These software tools can be used to demonstrate compliance with Section 6 of the Building Regulations and for producing EPCs. A comprehensive list of the approved FI-SBEM and DSM tools for use in Scotland can be found in the table below.

Demonstrating compliance under standard 6.1 - Carbon Dioxide Emissions

On submitting a building warrant application, the carbon compliance calculation required under standard 6.1 should be carried out using software, approved for use in Scotland, which implements:

• for dwellings, the edition of SAP current at the date on which the warrant application is made. In this respect, 'edition' refers to the dated edition of SAP (e.g. SAP 2005, SAP 2009) and not the version number (e.g. v9.80, v9.81)
• for non-domestic buildings, the version of the National Calculation Methodology (NCM) current at the date on which the warrant application is made. In this respect, 'version' refers to the full descriptor of the calculation tool (e.g changes implemented in iSBEM v3.5c or v4.1b), as incremental updates generally include changes to the assertions made or data used which may affect the calculation output
• However, as noted in clause 10/11 of the NCM Modelling guide for Scotland, software implementing the previous version of the NCM (i.e. calculation tool and NCM databases) may be used for a period not exceeding six months following introduction of a new version of the NCM, provided a change in regulations does not require use of the current version (as would be the case, for example, from 1 October 2010).

The edition/version of the relevant calculation methodology current at the date on which the warrant application is made would then be used for the duration of the project, including for any amendments to warrant, until works are complete. This ensures that requirements under standard 6.1 remain constant for the duration of the project and that action needed for compliance is unaffected by changes to the calculation methodology.

Whilst the same edition/version should be used for any amendment to the original warrant, at any stage applicants can elect to adopt a more recent edition/version. Having elected to do so however, applicants may not revert to use of a previous edition/version.

Information on the date of introduction of editions/versions of calculation methodologies, together with information on current approved calculation software tools can be found above.

Issue of Domestic or Non-domestic EPC with Completion Certificate under standard 6.9 - Energy Performance Certificates

Following completion of the proposed building, the Energy Performance Certificate which is to be submitted to the verifier with the completion certificate, should be produced using approved software which implements the current edition and version of the relevant calculation methodology. This ensures that building owners are presented with the most current and relevant information practicable.

This may result in use of a different version or edition of the relevant calculation method than was used for the carbon compliance calculation under standard 6.1. In such circumstances, the party responsible for producing the EPC will normally export the carbon compliance calculation into the current version of their chosen software tool. In exporting SAP 2005 to SAP 2009, for example, information on thermal mass and heat loss through separating walls may require to be defined. Similarly for the non-domestic calculation, in exporting SBEM v3.5 to v4.1 for example, information on the activities assigned to zones may need to be reviewed.

For production of non-domestic newbuild EPCs, approved software which implements the previous version of the NCM may be used, provided the current version has been released less than one calendar month prior to the assessment date and a change in regulations does not require use of the current version.