New BBA/TIMSA scheme cuts out SAP calculation concerns

It’s all change this month as we write on the formal launch of the BBA scheme to help sort out the confusing, and frankly disturbing, issue of wrong U value and condensation risk calculations being offered to building control and others. The BBA is not saying these are deliberate or designed to deceive, but to date the calculations providers and their customers have lacked a credible means of having their methods verified and approved by a recognised body with particular expertise in thermal issues, such as the BBA. That has now changed with the support of major insulation providers.

The BBA has formally launched its scheme for assessing and monitoring U value and condensation risk calculation competency to provide reassurance to the industry. The scheme, devised in association with the Thermal Insulation Manufacturers and Suppliers Association (TIMSA), involves major insulation players in the UK – Kingspan, Knauf, Recticel, Rockwool and SIG and has the backing of two of the premier U value software providers, JPA and BuildDesk. Scheme members are required to demonstrate appropriate technical competency and in-house procedural controls to ensure that their declared calculations are reasonable.

The assessment process consists of:

• an initial screening and assessment, based on sample calculations, designed to test the understanding of the underlying principles of BR443 and BS EN ISO 6946
• an office inspection to examine the company’s quality management system and examples of actual calculations
• issue of a certificate to the company that both identifies their competent person(s) and defines their individual areas of competency
• ongoing monitoring of members of the scheme.

SAP calculations and U value claims and counterclaims are now commonplace in the industry and the accuracy can vary.  A research report produced for Energy Efficiency Partnership for Housing and the DCLG in 2009, Research into Compliance with Part L of the Building Regulations for New Homes, highlighted that during construction Domestic Energy Assessors/SAP assessors are often provided with incorrect, incomplete or contradictory design information, with the most common offender being U values.

BBA chief executive Greg Cooper emphasises the importance of unbiased and independantly verified calculations: “With the increasing drive to reduce CO2 emissions, we need to make certain that emission rates are calculated correctly and there is little hope of that if the input values, such as U values, cannot be trusted.  We must provide accurate, objective and consistent U value and condensation risk calculations. The BBA/TIMSA scheme ensures that reliable information is provided to building control, specifiers, energy assessors and anyone interested in credible thermal data.

Using the services of accredited competent persons provides the client with confidence that the mechanics of the calculation have been carried out correctly and the thermal and vapour performance data used for the construction materials specified has been carefully examined. A list of approved sources of information for use can be found in the scheme document on the BBA website.

The scheme is open to non TIMSA members and anyone seeing reassurance that the calculations being provided are supplied by an individual or company that has been subject to rigorous and ongoing independent assessment process.

This is an extract of an article written by Alan Thomas. Alan Thomas is Sales and Communications Director at the British Board of Agrement. For more information visit www.bbacerts.co.uk     

This article appeared on page 18 and 19 of the Building Control Journal – June 2011   www.rics.org/journals