Overheating Analysis for Greater London Authority (CIBSE TM49)

Overheating risk analysis for buildings in Greater London Authority follows CIBSE TM52 methodology but uses the weather scenarios specifed in CIBSE TM49: Design Summer Years for London

CIBSE TM49 Weather Scenarios

DSY1 (Design Summer Year) for the 2020s, high emissions, 50% percentile scenario

DSY2 – 2003: a year with a very intense single warm spell.

DSY3 – 1976: a year with a prolonged period of sustained warmth.

Compliance Measures of TM52

Criterion 1 - Hours of Exceedance

Criterion 2 – Daily Weighted Exceedance

Criterion 3 - Upper Limit Temperature

Compliance Requirements of TM52

In TM52, a room or building that fails any two of the three criteria is classed as overheating.

How can we help you?

If your project is within the Greater Local Authority, we can assist you assess the risk of overheating. Please contact us on:


11 Caithness Crescent
Manor Kingsway
Derby DE22 3XS


01332 492082


0788 6277 818