Thermal Modelling

did you know... • Climate projections show that we will be facing more extreme weather in the coming years. Climate predictions for 2050 are frequently being seen today. • Domestic overheating assessments are now required. Part O provides a prescriptive methodology by which the assessment must be carried out. • The assessment of overheating risk varies between different methodologies. TM52, Part O and BB101 all use variations of a similar methodology but result different outputs. • Solar gains pose a significant risk to internal comfort. Dynamic solar analysis can assist with solar gain mitigation. • Insulation, external shading and orientation all play a part in ensuring comfortable buildings. Dynamic thermal modelling can show the impact of the Lean, Clean, Green, Seen methodology. • BREEAM assessments require future weather simulations for thermal modelling credits. 2050 and 2080 weather files must be used and a PMV (Predicted Mean Vote) and PPD (Predicted Percentage Dissatisfied) assessment must be carried out.

TM52: non domestic

Addresses overheating issues in domestic properties: • Can follow a simple or dynamic modelling methodology. - Simple method looks at glazing location, orientation, opening availability and cross ventilation. - Dynamic method looks to assess proposed building against prescriptive profiles and dynamic solar modelling. • Needs to demonstrate compliance against set criteria including night time comfort. • Openings must comply with fall risk potential through sill height, railings or opening restrictors. • Cannot include internal solar blinds. • Prescriptive internal gains and profiles must be used as set out by the methodology. Part O: domestic assessments

Addresses overheating issues in educational buildings: • Must account for the needs of the students and whether they have additional needs. • Must include predicted CO 2 assessments and mitigation measures. • Many assessments have restricted window allowances to reduce projectiles being thrown from height. • Classrooms and offices must each pass a separate set of criteria. • Overheating is assessed against the maximum acceptable temperature rather than TM52 or Part O criteria. • Prescriptive internal gains and profiles must be used as set out by the methodology. BB101: education assessments

Addresses overheating issues in non-domestic properties: • Must follow the design of the building, including proposed equipment, people, lighting and solar gains. • Must utilise accurate usage and mechanical systems profiles. • Must demonstrate compliance in all spaces or the building will not pass. • Can include internal solar blinds. • Must pass two of the three criteria set out in the TM52 methodology.

Innovation Centre, University of Essex

Purdy Street, Salthouse

Colchester Institute

Front cover: St Nicholas Drive, Caister on Sea