Amendments to building regulations approved documents A, B (volume 2) and C (WG 011/2017)

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Circular

Issued by:

Francois Samuel: Head of Building Regulations

Summary:

The purpose of this Circular is to draw attention to the amendments of Approved Documents: A (Structure), B Volume 2 (Fire Safety - Buildings other than dwellinghouses) and C (Site preparation and resistance to contaminants and moisture).

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THE BUILDING ACT 1984

THE BUILDING REGULATIONS 2010

Amendments to Approved Documents to support the following requirements of the Building Regulations 2010:

•PART A (STRUCTURE) OF SCHEDULE 1

•PART B (FIRE SAFETY) OF SCHEDULE 1

•PART C (SITE PREPERATION AND RESISTANCE TO CONTAMINANTS AND MOISTURE) OF SCHEDULE 1

Introduction

1.I am directed by the Welsh Ministers to draw your attention to the approval under Section 6 of the Building Act 1984 for amendments to the Approved Documents which support Part A (Structure), Part B (Fire Safety) and Part C (Site preparation and resistance to contaminants and moisture) of Schedule 1 to the Building Regulations 2010 as amended (S.I 2010/2214) (the “Building Regulations”). These amendments will take effect on 1 September 2017.

2.The purpose of this Circular is to:

•Provide guidance on the approval and publication of amendments to Approved Documents A, B (Volume 2) and C.

Scope

3. This Circular Letter applies to all building work carried out in Wales except building work on excepted energy buildings1 in Wales

Changes to Approved Documents

4Approved Documents provide statutory guidance on the application and compliance with the Building Regulations. An amendment slip, “Amendments to the Approved Document A, B and C”, is being published alongside this Circular on the Welsh Government website. The amendment slip outlines the amendments to Approved Documents A, B (Volume 2) and C.

5.A notice of approval of the amendments to the Approved Documents is at Annex A.

6.Annex B provides a summary of the changes to the Approved Documents and additional guidance.

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7.An electronic copy of the “Amendments to the Approved Document Part A, B and C” is available from www.wales.gov.uk/topics/planning/buildingregs

Enquiries

8.If you have any queries regarding this Circular, please contact:

Building Regulations

Planning Directorate

Welsh Government

Rhyd y Car

Merthyr Tydfil

CF48 1UZ

Tel : 0300 062 8646

E-mail : enquiries.brconstruction@wales.gsi.gov.uk

Yours faithfully,

Francois Samuel

Head of Building Regulations

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Annex A

Building Act 1984

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Annex B

REVISIONS TO APPROVED DOCUMENTS A (STRUCTURE), B VOLUME 2 (FIRE SAFETY) AND C (SITE PREPARATION AND RESISTANCE TO CONTAMINANTS AND MOISTURE)

Revisions to Approved Document A (Structure)

There is no change to Part A of Schedule 1 to the Building Regulations 2010 (as amended).

The main change to Approved Document A (Structure) has been updating of the references to structural design standards, to refer to the current British Standards for structural design, these will replace the references to standards withdrawn by the British Standards Institution (BSi) on 31 March 2010. The current British Standards are based on a suite of common European design standards, the Eurocodes, which provide a unified approach to structural design across the European Union.

It is likely that some structural designs will continue to be completed using the withdrawn British Standards. This approach may be considered appropriate given the functional nature of Building Regulations. Building Control Bodies assessing compliance with the Building Regulations will need to consider the use of these standards on a case by case basis. Where the use of the withdrawn British Standards is proposed, it should be remembered that BSi might not be maintaining withdrawn British Standards, and typically, a British Standard is subject to review and revision every five years. However the use of withdrawn standards may continue to remain where a designer/engineer is able to demonstrate to the building control body it is appropriate for the particular structure proposed. Such an approach is likely to be more appropriate for smaller-scale, less complex, lower-risk designs, and where designers/engineers have appropriate skills and competencies. It would be appropriate to refer to the relevant guidance in the 2004 edition of Approved Document A where the use of recently withdrawn standards is proposed.

Building Control Bodies will need to be aware of the safety risks when inappropriately mixing structural designs based on both the new and the withdrawn British Standards.

There are also additional minor changes to the guidance in Approved Document A to align it with new design standards which reflects common practice for strip foundations in shrinkable clay soils, and on re-covering of roofs.

Revisions to Approved Document B Volume 2 (Fire Safety)

There is no change to Part B of Schedule 1 to the Building Regulations 2010 (as amended).

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The main change to Approved Document B Volume 2 is with regard to table 10 and 11. Table 10 (Classification of linings) has been changed in relation to wallcoverings which conform to BSEN 15102:2007 Decorative wallcoverings – roll and panel form products.

Table 11 (Limitations applied to thermoplastic rooflights and lighting diffusers in suspended ceilings and Class 3 plastic rooflights) has been changed to incorporate more flexible guidance for small diffusers and rooflights.

Revisions to Approved Document C (Site preparation and resistance to contaminants and moisture)

There is no change to Part C of Schedule one to the Building Regulations 2010 (as amended).

The main change to Approved Document C (Site preparation and resistance to contaminants and moisture) is the amendment to reflect the latest 2007 radon mapping by Public Health England (PHE) (formerly the Health Protection Agency) and the British Geological Survey (BGS). This is to ensure that the requirement for radon protective measures is targeted at the right areas. This includes updated references to the BRE publication BR211 Radon: Guidance on protective measures for new buildings 2015, the PHE and BGS radon website addresses, and to guidance on radon in the workplace.

Attention, in particular, is drawn to the revised guidance in paragraph 2.40 which is intended to inform Building Control Bodies and applicants of how alternative radon risk reports can provide a more accurate assessment of whether radon protection is necessary and, where necessary, the level of protection that is appropriate.

Additionally, Approved Document C guidance has been amended in the site investigation section to reference the new structural design British Standard for geotechnics to reflect current guidance on contaminated land, (including the deletion of Annex A). There are also updated guidance references in relation to flooding, condensation and mould growth.