This type of assessment reviews in detail, usually on a room by room basis, if the development has a risk of overheating in summer months. The methodology is more adequate than other methods used to review if the proposed design has any risk to future occupiers.
To have accurate results, it is fundamental to use dynamic simulation, including specific weather conditions for a location, assessing it on an hourly basis (24 hours by 365 days per year). Other calculations, such as Criterion 3 of Approved Document Part L of Building Regulations in the UK, use a steady state analysis with average monthly temperatures and other assumptions that provide inadequate results. CIBSE standards also take into account project specific characteristics of the development, including windows types with free areas, enabling more accurate results and prediction of overheating risk.
This type of assessments provides detailed results to enable informed design decisions regarding building form, materials and ventilation strategies. This evaluation reduces the risk of overheating in buildings. Assessments such as CIBSE TM49 and its weather files enables designers to analyse the summer performance of their buildings and investigate the impact of urban macroclimatic factors and climate change when carrying out overheating risk assessments for buildings in London.
“The Part L overheating assessment is relatively simplistic, thus potentially leading to inappropriate design decisions regarding building form, materials and ventilation strategies.” CIBSE Technical Symposium, Dublin, Ireland, April 2014.
Greater London Authority (GLA) London Plan, Guidance on Preparing Energy Statements now include specific requirements on dynamic thermal modelling at the detailed planning stage to quantify the risk of overheating as per current and future climatic conditions. CIBSE Standards include:
134-146 CURTAIN ROAD.
BLOCK B SOUTHGATE
SCHOOL OFFICE BLOCK
BEAL HIGH SCHOOL
GORING FIRST AID
DAVISON HIGH SCHOOL
West Acton primary