When Do I Need an SBEM Calculation? Part L2 Guide | ATSPACE

SBEM Calculations

When looking at the practical SBEM meaning, it refers to the Simplified Building Energy Model used across England and Wales. SBEM calculations are the national calculation methodology used to demonstrate compliance with Building Regulations Approved Document L2 (Conservation of fuel and power in buildings other than dwellings). An assessment is required when constructing a new non-domestic building, erecting large commercial extensions, or completing certain material changes of use and fit-outs. The calculation produces a Building Regulations UK Part L (BRUKL) report showing whether the building design satisfies statutory energy efficiency and carbon benchmarks. Building Control requires this documentation to confirm compliance before work begins on site and at final completion.

Statutory Compliance Targets: BER vs TER and BPER vs TPER

Under Approved Document L Volume 2, a non-domestic building must satisfy two primary performance targets simultaneously:

• Building Emission Rate (BER) vs Target Emission Rate (TER): The calculated BER (expressed in kgCO2/(m2·year)) must not exceed the target set by a reference building of the same size, geometry, and servicing recipe.
• Building Primary Energy Rate (BPER) vs Target Primary Energy Rate (TPER): Introduced in the 2021 standards, the calculated BPER (in kWh_PE/(m2·year)) must not exceed the target primary energy consumption threshold, ensuring energy efficiency in procurement and distribution.

If you are reviewing building specifications or require guidance through compliance targets, the commercial team at ATSPACE provides design reviews within 5 to 10 working days, with initial quotes issued the same day for requests received between 8am and 4pm Monday to Friday.

When Is an SBEM Assessment Legally Required?

In regulatory terms, the core SBEM meaning is demonstrating to Building Control that your non-domestic design satisfies statutory energy standards. An SBEM calculation is legally mandated under Approved Document L2 across the following commercial scenarios:

• New Commercial Builds: All newly constructed buildings other than dwellings, including offices, industrial units, retail warehouses, care homes, schools, and hotels.
• Shell and Core Developments: Speculative builds where base building services are installed prior to tenant fit-out require a base SBEM model, followed by fit-out assessments.
• Commercial Extensions and Fit-outs: Non-domestic extensions with a total useful floor area greater than 100 m2 that are also greater than 25% of the total useful floor area of the existing building, or extensions introducing new fixed building services.
• Material Change of Use: Buildings converting from domestic to commercial use, or unheated spaces converted into heated commercial facilities.

The Two-Stage SBEM Compliance Process

1. Design Stage (Prior to Construction): SBEM calculations should be submitted to the Building Control Body alongside detailed drawings, fabric specifications (U-values of walls, floors, roofs, and glazing), air permeability targets, and mechanical plant data (heating, cooling, ventilation, and lighting controls). Building Control requires this design-stage BRUKL output before approving the commencement of site operations.
2. As-Built Stage (Prior to Sign-off): Once construction is complete, the SBEM model is updated with true as-built specifications, signed commissioning certificates, and air leakage test results (usually requiring an air permeability test result of 5.0 m3/(h·m2) at 50 Pa or better for non-domestic assets). Once confirmed by the accredited energy assessor, the final As-Built BRUKL report and Commercial Energy Performance Certificate (EPC) are produced for Building Control sign-off.

For domestic properties such as houses or residential flats, compliance is modelled via a SAP calculation using the SAP 10.2 methodology. For commercial developers and contractors, the true SBEM meaning on site is securing a reliable compliance calculation before breaking ground and achieving sign-off without disruption.