Assessing external wall cladding for fire spread (WG 010/2018)

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Circular

Issued by:

Francois Samuel: Head of Building Regulations

Summary:

The purpose of this Circular Letter is to draw attention to issues about assessments of external wall cladding systems.

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ASSESSMENTS OF EXTERNAL WALL CLADDING SYSTEMS

The purpose of this Circular Letter is to draw attention to issues about assessments of external wall cladding systems.

SCOPE OF THE CIRCULAR LETTER

The guidance in this Circular Letter applies to buildings and building work in Wales.

This guidance is principally relevant to projects for which a full plans application is made or initial notice submitted from the date of this letter. However, for existing projects, building control bodies may wish to reconfirm that satisfactory evidence has been submitted that the requirements of paragraph B4 of Schedule 1 are being met.

INTRODUCTION

The UK Government has recently consulted on amendments to the guidance in Approved Document B to restrict the use of assessments in lieu of tests. This reflects concerns reported in Dame Judith Hackitt’s report into Building Regulations and Fire Safety, and raised by many others, that assessments have been used inappropriately to support proposals for cladding systems. Welsh Ministers share these concerns.

Welsh Ministers have recently consulted on proposals to ban the use of combustible materials in external wall systems for high rise residential buildings. A ban would remove the option for developers to use an assessment in lieu of a test (sometimes referred to as a “desktop study”) to demonstrate compliance for external fire spread on external walls.

Pending Welsh Ministers decision on the outcome of the consultation, this letter provides guidance to building control bodies on how they should be assessing compliance with the requirements of Paragraph B4 of Schedule 1 to the Building Regulations 2010 as amended.

GUIDANCE

Section 13 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.

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Welsh Ministers take the view that, pending decisions following the consultation, and the publication of any new standard, building control bodies should only accept evidence of either of these two ways to demonstrate compliance.

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.

ENQUIRIES

All enquiries on matters covered by this Circular should be addressed to:

Building Regulations

Welsh Government

1st Floor, North

Rhydycar

Merthyr Tydfil

CF48 1UZ

Tel: 03000 628144

E-mail: enquiries.brconstruction@gov.wales

Yours faithfully

Francois Samuel

Head of Building Regulations Policy Planning Directorate

Welsh Government