Overheating Calculations - Part O Compliance

Overheating Calculations use the recently published standards set out in Part O Building Regulations and TM59 to reduce the build-up of heat within a building. Part O came in to effect in England in June 2022 and focuses on the importance of a building's design in relation to mitigating solar gain during summer months while providing the end-user with sufficient means of removing excess heat from an internal area. Two methods for testing overheating are specified in Part O of the Building Regulations:

• The first method, referred to as the “simplified method”, establishes maximum glazing amounts and minimum free opening areas that may be used in buildings and rooms to reduce solar gain and dissipate extra heat.
• The second method, Dynamic Thermal Simulation Modelling, offers more precise overheating risk analysis while allowing for greater design freedom.

We complete Overheating Calculations by using either of the two aforementioned methods. The “simplified method” is used when a proposed building does not appear to be overglazed. This method is not suitable for buildings with more than one residential unit that uses a communal heating or hot water system which has a significant amount of vertical pipework. If a building appears to be overglazed, has more than one residential unit with a communal system or does not pass the “simplified method”, then the Dynamic Thermal Simulation Modelling Software is used.

This software enables us to create an accurate representation of the proposed building which will then be analysed todetermine the building's performance in terms of overheating in regard to the specific criteria set by the CIBSE (Chartered Institute of Building Services Engineers). There are different types of criteria for different areas within the UK, dependant upon location. These are categorised into “high risk” and “moderate risk” areas.

Once the proposed building has been tested and analysed a result will be generated, indicating whether or not the model has passed the specific criteria and is compliant with Part O. If certain parts of the proposed building do not comply with Part O Building Regulations then we will advise you on how to improve the building to ensure it is compliant. Part O states that the building should use passive means to limit unwanted solar gain as much as possible. This must be demonstrated to the Building Control Body before mechanical means are even considered to ensure that all passive strategies have been reviewed.

Please do not hesitate to contact us should you require advice or assistance.