Government issues advice to building control bodies on assessments of external wall cladding systems

The Government has recently consulted on amendments to the guidance in Approved Document B to restrict the use of assessments in lieu of tests and proposals to ban the use of combustible materials in external wall systems for high rise residential buildings. 

Pending the Government decision on the outcomes of those consultations, MHCLG has issued a circular to all building control bodies providing guidance on how they should be assessing compliance with the requirements of Paragraph B4 of Schedule 1 to the Building Regulations 2010 as amended.

Current Guidance

Section 12 of Volume 2 of Approved Document B (Fire safety – buildings other than dwelling houses) sets out two ways for duty holders to demonstrate compliance with the requirements of Paragraph B4 of Schedule 1 (External Fire Spread) to the Building Regulations 2010 as amended, in relation to buildings with a storey 18m or more above ground level.

These are:

• for any insulation product, filler materials (not including gaskets, sealants and similar) etc used in the external wall construction to be of limited combustibility (as defined in Table A 7 of Appendix A of Volume 2 of Approved Document B); or
• for the external wall to meet the performance criteria given in the BRE report Fire performance of external thermal insulation for walls of multi storey buildings (BR 135) for cladding systems using full scale test data from BS 8414 -1: 2002 or BS 8414-2: 2005.

The Government takes the view that, pending decisions following the consultations, and the publication of any new standard, building control bodies should only accept evidence of either of these two ways to demonstrate compliance with the requirements of the building regulations.  Building control bodies should look for clear evidence of the classification of materials used, to meet the definitions in Table A7 of Appendix A; or clear evidence of the results of tests carried out in accordance with BS 8414.  Test results must be relevant and appropriate for the proposed external wall construction.  Building control bodies should not accept proposals which lack such evidence.

The full circular can be found here.

For advice and guidance on what this means for you or your project please contact your NHBC Building Surveyor.