Fire Safety: clarification of statutory guidance – what next for 12.7?

Introduction

On 19 July 2018, the Ministry of Housing, Communities and Local Government initiated an open consultation aimed at seeking views on proposals to clarify fire safety statutory guidance as set out in Approved Document B.

To review the consultation please click here.  

As regular readers of our cladding focused blog posts will be aware the Approved Documents provide practical guidance in respect of Schedule 1 (requirements) to Regulation 7 of the Building Regulations. Historically, the Approved Documents are updated every 6 to 8 years in parallel with innovations and advancements in the technology, scientific and construction sectors. However, the current proposed amendments have arisen following concerns regarding building safety following the Grenfell tragedy.

Background

The Government considers the proposed amendments to Approved Document B will “improve usability and reduce the risk of misinterpretation by those carrying out and inspecting building works”. The consultation follows the Secretary of State’s commitment in Parliament on 17 May 2018 to consult on building regulations and fire safety. This commitment arose following Dame Judith Hackitt’s Independent Review of Building Regulations and Fire Safety which highlighted that fire safety statutory guidance, including Approved Document B is not fit for purpose. For more information regarding Dame Judith’s review, please read our blog posts as follows:

Hackitt Final Report blog series: Week 1 - The creation of a new Joint Competent Authority

Hackitt Final Report blog series: Week 2 - Governance roles in Government

Hackitt Final Report blog series: Week 3 - The new regulatory framework

Hackitt Final Report blog series: Week 4 - Products

The consultation closes on 11 October 2018. Following the consultation (which is broadly aimed at industry experts and those involved in the life cycle of a construction project), the Ministry of Housing, Communities and Local Government will produce a “detailed impact assessment” which in turn will inform the Government’s decision on any necessary amendments to policy.

Key proposed changes

They key clarification points of the review are as follows:

1. restricting the use of assessments in lieu of tests (i.e. potentially banning desktop studies), and
2. revised guidance on the use of combustible materials in the external walls of high-rise buildings.

Both the above (desktop studies and consideration of the use of combustible materials) are also subject to separate government consultations. Further details can be located here:

Approved Document B (fire safety): amendments to statutory guidance on assessments in lieu of tests

Banning the use of combustible materials in the external walls of high-rise residential buildings

In addition to the above, the updates to Approved Document B are focused on applying a “plain English approach” and in implementing significant reconfiguration – in particular focusing on the split between ‘dwelling houses’ and ‘all other buildings’ as brought about by a reformatting of Approved Document B in 2006. 

Section 12.7 of the current Approved Document B – Volume 2

Under the current version of Approved Document B Volume 2 – buildings other than Dwelling Houses, there are two options for the compliance, in respect of external walls, these are as follows:

1. external walls should either meet the performance criteria provided in BR 135, or
2. meet the guidance set out in paragraphs 12.6 to 12.9.

In respect of option 2 above, paragraph 12.7 is typically the key compliance hurdle to overcome and is the section of the guidance that has caused the most controversy since the Grenfell tragedy. Paragraph 12.7, as it currently stands is set out below:

Insulation Materials/Products

"12.7 In a building with a storey 18m or more above ground level any insulation product, filler material (not including gaskets, sealants and similar) etc. used in the external wall construction should be of limited combustibility (see Appendix A). This restriction does not apply to masonry cavity wall construction which complies with Diagram 34 in Section 9."

There are two key reasons for issues in respect of paragraph 12.7. These are as follows:

1. the requirement for some parts of the wall build-up to be “of limited combustibility”, and
2. the debate concerning whether “insulation product, filler material…..etc” includes the core of an ACM panel.
   In respect of the latter, the Department of Communities and Local Government’s now widely circulated letter dated 22 June 2017, published following the Grenfell tragedy, confirmed the following:

"For the avoidance of doubt; the core (filler) within an Aluminium Composite Material (ACM) is an "insulation material/product", "insulation product", and/or "filler material" as referred to in Paragraph 12.7 ("Insulation Materials/Products") in Section 12 "Construction of external walls" of Approved Document B (Fire safety) Volume 2 Building other than dwelling houses. (The important point to note is that Paragraph 12.7 does not just apply to thermal insulation within the wall construction, but applies to any element of the cladding system, including, therefore, the core of the ACM)."

However, following the Government’s letter and the focus of the consultation on desktop studies and materials of limited combustibility, what exactly has been proposed for the “new 12.7”?

Set out below is the proposed draft text: 

Section 13: Resisting fire spread over external walls

"13.1 To reduce the risk of fire spreading over the external walls, where a building with a storey 18m or more above ground level, materials in or on the external walls should meet class A2-s3, d2 or better (not including gaskets, sealants, and other components exempted under Regulation [ ]).

a. Materials that do not meet class A2-s3, d2 or better can be used if they are enclosed within the cavity of masonry cavity walls that comply with diagram 8.2.

NOTE: Cavity barriers should be provided in accordance with section 8.

NOTE: The total amount of combustible material may also be limited to meet the need to resist fire spread from one building to another (see section 11).

13.2 As an alternative to 13.1, external walls should meet the performance criteria given in BRE report BR 135, using full-scale test results from BS 8414-1 or BS 8414-2."

While the above is in draft format, and is specifically stated as being subject to the Government’s consultation regarding banning the use of combustible materials (and therefore appears to be a long way from its final form) the following key points are of interest:

1. Gone is the reference to “insulation product, filler material…..etc” which appears to have been replaced with: “materials in or on the external wall”. The latter appears to be a broad and inclusive description which could arguably refer to any material (including potentially the core of an ACM panel) contained in the external wall build-up. Interestingly, the use of the term “etc” has been removed. It is arguable that the use of “etc” following a list of items dictates that the restriction referred to only applies to items that are analogous to those listed. The point being that in removing “etc” the description arguable becomes wider and more inclusive. However, the key question is whether this new description provides much needed clarity in respect of which specific materials in a wall build-up are subject to the compliance requirements?
2. It is no longer a requirement that the relevant materials have to be “of limited combustibility”, the relevant materials are now required to meet class “A2-s3, d2 or better”. This is an EU classification to standard EN-13501-1. Table A7 of the current version of Approved Document B defines “materials of limited combustibility”. Within this table, under a column titled: “European Class” it states that “any material/product classified as Class A2-s3, d2 or better in accordance with BS EN 13501-1:2007” falls within the definition. However, a note at the foot of table A7 confirms the following: “The National classifications do not automatically equate with the equivalent classifications in the Europe column; therefore, products cannot typically assume a European class unless they have been tested accordingly”. Whether this provides better clarity in respect of the performance of materials in a wall build-up will be a question to be considered by industry professionals and testing experts.
3. Materials that do not meet class A2 or better can be contained in the wall build-up provided they comply with diagram 8.2 which prescribes for a wall comprising two leaves of brick concrete each of at lease 75mm thick with the combustible materials placed within the cavity. This appears onerous and unwieldy for a standard construction project.
4. The option for the wall build-up in its entirety, to comply with BR 135 using full scale test data from BS 8414-1 or BS 8414-2 (as provided for in the current version of 12.7) is still available. In light of the Government’s consultation regarding the use of desktop studies, in the event that the decision is to enact an outright ban of desk top studies, this is likely to mean that it will therefore not be possible to demonstrate compliance with BR 135 via a desktop study. It therefore appears likely that this route to compliance will become less popular. This is because carrying out a full-scale fire test to BR 135, as opposed to relying on previously available test data by way of a desk top study, is an expensive and time-consuming task.
5. In light of the above, it appears the Government is planning some significant and wholescale changes to the routes to compliance in respect of external walls. It remains to be seen what the industry will think of these proposed amendments and whether they meet the Government’s proposed outcomes.