Building Sciences

Thermal Calculations and FEA

Thermal Calculations

The thermal performance of elements of the building fabric is assessed by way of the U Value which is a measure of the thermal transmittance through plane areas of the walls, roof, floor, etc. Calculations may be undertaken in accordance with the BS EN ISO 6947: 2007 combined method to assess the U Values and interstitial condensation risk for a wide range of construction types.

Where the building fabric elements comprise complex non-uniform geometry or non-repeating thermal bridges, then assessment by way of a Numerical Modelling tool may be required.

FEA Numerical Modelling

Building Sciences has gained extensive experience in the use of Finite Element Analysis (FEA) to determine the thermal performance of building fabric components and interfaces for a wide variety of construction types and systems. Thermal FEA modelling is undertaken in accordance with BS EN ISO 10211: 2001, subject to BS EN 13370: 1998, BS EN ISO 6947: 2007, and the guidance in BRE publications BR443 and BR 497 (accepted conventions for thermal calculations) and BRE IP 1/07.

FEA is undertaken within the Strand 7ô environment to assess the thermal transmittance through designed components and interfaces and may be used to determine resultant U Values (Area thermal transmittances), ? Values (Linear thermal transmittances ñ thermal bridging) and É factors (Minimum internal temperature factors).

The results of such analysis may be used to demonstrate compliance with the requirements of the Building Regulations for a thermally efficient building via the NCM tools. Further, the output may be interrogated to identify potential problems such as internal surface condensation and mould growth. Designs may then be amended and remodelled to minimise such risks.

FEA of components and interfaces may also be undertaken alongside our building fabric Defect Investigation Services to assess the difference in thermal performance between as-designed and as-built conditions. Such analysis/diagnosis may prove invaluable in dispute resolution circumstances.