National Calculation Method NCM
The National Calculation Method (NCM) is defined by the Department for Communities and Local Government (DCLG). It describes the procedure, for buildings other than dwellings, for demonstrating compliance with the carbon emission requirements of regulation 17C of the Building Regulations and for calculating ‘operational ratings’ and ‘asset ratings’ in the production of Energy Performance Certificates (EPC’s) in relation to the Energy Performance of Buildings Directive (EPBD).
The NCM provides the underlying method and the standard data sets necessary to calculate the annual energy use of a proposed building and comparing it with the energy use of a ‘notional' building of a similar type, under similar circumstances. This is done by calculating the Target Emission Rate (TER - the CO2 emission rate) for the notional building and comparing it with the Building Emission Rate (BER) for the proposed building. The BER must not be higher than the TER.
The calculations can be performed using approved simulation software (Approved Dynamic Simulation Models (DSMs)) or by using the Simplified Building Energy Model (SBEM), a ‘simplified’ compliance tool developed by BRE, which has a user interface called iSBEM.
 Related articles on Designing buildings Wiki
- Approved documents.
- Building Regulations.
- Emission rates.
- Energy Performance Certificates.
- Energy Performance of Buildings Directive.
- Simplified Building Energy Model.
- Standard Assessment Procedure.
 External references
- National Calculation Method.
- National Calculation Methodology (NCM) modelling guide (for buildings other than dwellings in England and Wales) 2010 Edition.
Featured articles and news
Read our introductory article to the different types of structural load.
Erno Goldfinger's family home and modernist masterpiece - 2 Willow Road, Hampstead.
IHBC article asks - is the Bonfield Review blind to traditional buildings?
Do you know what an onigawara is? Find out here.
German Finance Minister Wolfgang Schäuble on how to achieve a better investment framework for Africa.
3 ways the world’s fastest growing economies can close the infrastructure gap.
The sooner early warning notices can be appreciated as of mutual benefit rather than one-sided advantage, the better.
BSRIA responds to government green storage announcement.
What is phenomenology and how does it relate to the built environment?
Read about Belgrade's Brutalist landmark - the Western City Gate.
Read about the measures that can be taken by individuals to protect and minimise exposure to outdoor sourced air pollution.