As the headline suggests, the new Part O Approved Document now requires all properties to demonstrate mitigation measures for limiting overheating. Until now this has was previously a part of the SAP calculation however it's long been criticised as being too simple and crude of a method.
The previous SAP method used a steady-state methodology , incorrect assumptions on operative profiles and optimistic natural ventilation inclusions for assessing summer overheating. The requirements now stipulate either one of two methods to demonstrate compliance under the new regulations. The first is a simple assessment, however this places restrictions of glazing ratios dependent of floor area, limitations on orientation and ventilation strategies.
The more flexible approach uses dynamic 3D modelling of the buildings thermal properties and glazing specification to simulate of airflow, sun path, shading and local weather data to accurately calculate the internal and external temperatures and environmental conditions.
A full explanation of the advantages and disadvantages of both are detailed on our services Overheating Analysis page together with pricing and answered FAQ's and further advice for building designers .
How to avoid failure!
We know most properties will struggle to gain compliance using common building design methods and specifications without the inclusion of passive mitigation measures. We therefore suggest early appointment to avoid replanning and abortive design costs for all projects under the new 2021 Building Regulations.
Approved Document Part O
Download your copy of the new Approved Document Part O below.
Want To Know More About The Other Important Changes To The 2021 Regulations?
To see all our guidance articles on the changes to the Approved Documents 2021, make sure your visit our 2021 Buildings Regulations page.
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