Grenfell Tower: the Government’s denial of responsibility

I argued in my last post that the Government bears the primary responsibility for the Grenfell Tower fire because:

i) the polyethylene-cored ACM panels were the primary cause of the inferno;

ii) they had been known by the Government to be dangerous since 1999, if not before;

iii) they were nevertheless permitted to be used on high rise residential buildings, under the official Approved Document guidance.

I also made reference to my father’s observation that in the aftermath of terrible accidents, all the parties concerned seek to avoid liability and culpability for what has happened. If he was right, then we might expect the Government to evade their responsibility for the Grenfell fire.

They have done exactly this. Four days after the fire, on Sunday morning 18 June 2017, Philip Hammond, the Chancellor, claimed on the Andrew Marr Show that the cladding that was used on Grenfell tower was banned in the UK:

It seems fairly clear that by ‘the cladding’ and ‘this flammable cladding’, Marr and Hammond are making reference to the ACM cladding panels, rather than to another element of the cladding system, or to the system as a whole. Extraordinarily, Hammond appeared to be claiming that the Reynobond PE ACM panels used at Grenfell were banned in England and Wales, when in fact they were not, even on high rise buildings.

That this was indeed the Government position was confirmed in a letter sent later the same day by Melanie Dawes, Permanent Secretary at the Department for Communities and Local Government (DCLG), to the Chief Executives of the Local Authorities and the Housing Associations. She claimed that the official guidance required the ACM core to be composed of a material of ‘limited combustibility’, as defined in Approved Document B2 at Table A7, or be Euro Class A2 or better: 1

The Reynobond® PE panels were not a material of ‘limited combustibility’, and they were Euro Class B, not A2. So if what Dawes wrote were true, then Hammond’s claim that the panels had been banned would have been accurate enough (even if it would have been more precise for him to have said that they were not in compliance with the official guidance).

But both Dawes and Hammond were wrong. The building regulation guidance requires cladding panels to be national Class 0 or Euro Class B only, and the Reynobond® panels were compliant. In what follows, I will first show simply that this is the only reasonable reading of the relevant section of the guidance, and then record the three alternative justifications provided by the Government for their alternative reading of it. The first of these, that the ACM core is possibly 2  an insulation material or product, I show to be false in my explanation of the guidance, and in a few extra words at the conclusion of the post. In two subsequent posts, I will attempt to prove that neither of the Government’s two further arguments are sustainable under examination.

The Approved Document guidance

The statutory Building Regulations 2010 require that buildings should adequately resist the spread of fire over their external walls:

The official Government guidance on how to meet this requirement is contained in sections 12.5 to 12.9 of Approved Document B ‘Fire Safety’, Volume 2 (AD B2). It begins with a caution that combustible materials may provide a medium for fire spread:

It is not said here that combustible materials should not be used in cladding systems, nor have I seen any suggestion by the Government that such a meaning can be construed. Rather, what I think we have here is an introductory remark, pointing out the potential risk involved. Because of this risk, I believe it is being said, the succeeding guidance should be followed.

The next paragraph of 12.5 offers two alternative routes to compliance. One, commonly known as the ‘Linear’ route, is taken by ensuring that all the individual components of the cladding system meet certain requirements, which are to be specified in the following sections 12.6 to 12.9. The other, which I will call the ‘System’ route, is followed by subjecting the whole system to a large-scale test. The manner in which the test is conducted is defined in two British Standards, BS 8414-1 and BS 8414-2, and the criteria by which success or failure is determined is given in the Building Research Establishment’s publication BR 135:

It is the Linear Route that is relevant here, as it is the fire safety requirements for ACM panels, which are a system component, which are at issue. Section 12.6 specifies requirements for the external surfaces of walls. Since ACM panels are on the outer layer of the system, they have to satisfy these: 3

For residential buildings over 18 m high, and more than 1 m from any neighbouring building, the relevant provisions are given in Diagram 40.e:

At heights over 18 m, the surfaces should have either a national Class 0 rating (0 being the highest surface grade), or a Euro Class B rating. The two are broadly equivalent and both are based on tests in which the surface of the material or product is assaulted by heat and flame.

The aluminium surface of ACM panels generally survives the rigours of the surface tests, so that even PE ACM panels, with their highly combustible polyethylene core, can achieve the necessary ratings. In particular, the Reynobond® PE panels used at Grenfell Tower were certified by the BBA and others as both national Class 0 and Euro Class B. Here, for example, is the relevant part of the BBA Certificate, issued in 2008, covering both the PE and the FR models of the product: 4

The ‘standard sample’ was Reynobond® PE, and it achieved Euro Class B-s2, d0 by test, and national Class 0 by a process of reasoning from the results of other tests.

Section 12.7 of AD B2

To achieve compliance by the Linear Route with the requirements of AD B2, a cladding system must also satisfy the requirements of Section 12.7:

We may start with the heading, which indicates that the requirement applies to ‘Insulation Materials/Products’. Are ACM panels insulation materials/products? The answer, definitely, is that they are not. In the UK context, where there has generally been a need to install extra insulation on the external walls, ACM panels have been used, as they were at Grenfell, as part of a system which includes insulation also. A cavity between the outer cladding panels, which provide a ‘rainscreen’, and the insulation boards, allows for evaporation of moisture vapour and for drainage. There are two types of rainscreen system, one pressure equalised and one not, but both allow a flow of air through the cavity: 5

Now, since the air is flowing between the cavity and the outside air, there is little temperature difference between the two. Therefore the thermal insulation is provided by the insulation boards and not by the cladding panels. It follows that the panels are not insulation products or materials and so are not subject to the limited combustibility requirement of 12.7. They only have to meet the national Class 0/Euro Class B requirement of 12.6, and this the Reynobond® PE panels used at Grenfell had done.

The Government’s attempt to justify its claim

On 3 July 2017, the Communities Secretary Sajid Javid told Parliament that cladding panels were subject to a

‘limited combustibility requirement’,

making reference to an ‘explanatory note’ to which a link was provided in the transcript of Javid’s statement:

This Explanatory Note on safety checks and testing had been issued by the DCLG on 30 June. It contained two Annexes, the second of which, ‘Annex B: Emergency Fire Safety Review’, had been issued previously as Annex A to a letter on ‘Safety checks following Grenfell Tower fire‘ sent on the 22 June 2017 by Melanie Dawes to the Chief Executives.

This Annex B of the Explanatory Note of 30 June refers in its first paragraph to

the insulation within Aluminium Composite Material

thus claiming in effect that the ACM core is an insulation material:

Footnote 4 reads:

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 Buildings 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).

Three possible rationales are provided for including the core of the ACM under the limited combustibility requirement of paragraph 12.7:

1. The ACM core is an insulation material or product;

2. The ACM core is a filler material;

3. All elements of the cladding system are covered, and so the ACM core is covered.

The first two are connected by an ‘and/or’. It is therefore claimed that one of the following is true:

i) The ACM core is an insulation material but not a filler material;

ii) The ACM core is a filler material but not an insulation material;

iii) The ACM core is both an insulation material and a filler material.

It follows that the DCLG is:

a) uncertain whether the ACM core is an insulation material; and

b) uncertain whether the ACM core is a filler material; but

c) certain that the ACM core is either an insulation material, or a filler material, or both.

And this is said for the ‘avoidance of doubt’! If the DCLG is unsure of ‘a’, and unsure of ‘b’, on what basis is it certain of ‘c’? And how can it be that the DCLG is uncertain how to interpret regulations that it itself wrote, and which it has the oversight of?

It seems to me that if the DCLG is uncertain whether the ACM core is an insulation material, and uncertain whether it is a filler material, then it cannot be certain that it is either of these. Perhaps it is with this consideration partly in mind that the DCLG adds its final parenthetical sentence and the third rationale. Even if the ACM core is neither an insulation material, nor a filler material, it would then still be covered by 12.7, since it is an element of the cladding system, and all elements are claimed to be covered.

I examine each of these rationales in turn, beginning with the first, which can be disposed of the most simply.

A) Is the ACM core an insulation material or product?

The relevant part of footnote 4 is:

For the avoidance of doubt; the core (filler) within an Aluminium Composite Material (ACM) is an “insulation material/product”, “insulation product”, and/or ...

We saw earlier that ACM panels have no insulation function in a rainscreen cladding system because air flows freely through the cavity.

Arconic, the manufacturer of the Reynobond® PE panels that were used at Grenfell Tower, describes the function of the core as being to add ‘strength and rigidity’ to the panels:

Nowhere, to my knowledge, does the manufacturer claim that its product has any insulation function.

It seems to me, therefore, that the ACM core cannot be considered an insulation material or product. So far as I am aware, the Government has not repeated its claim that it can be, in any public document issued since the Explanatory Note of 30 June. I have been informed by a journalist that the Government was still in December relying on footnote 4 of the Explanatory Note to justify its position that the AD B2 guidance did not allow combustible ACM panels on high rise buildings under the Linear Route. In theory, then, the claim that the core is an insulation material has not been completely abandoned by the Government. From a practical point of view, however, I think it may be discounted as constituting any more a plank of the Government’s defence. All that remains are the second and third rationales, which I examine and criticise in detail in my next two posts.

An historical implication

If it is accepted that the Government is no longer putting any weight on the notion that the ACM core is an insulation material, then it follows that they must be claiming in effect that a ban on combustible ACM cladding on high rise buildings under the Linear Route was introduced in England and Wales in 2007 (in what was called the 2006 edition). The reason is that the second and third rationales both rely on terms introduced to the limited combustibility requirement in that year.

In the previous 2000 edition (with 2000 and 2002 amendments) the requirement stood as a part of section 13.7, ‘External wall construction’, and read as follows:

In the 2006 edition, the entirety of  section 12.7, ‘Insulation Materials/Products’, was given to the limited combustibility requirement, and it took the form it retains today:

The Government’s second rationale relies on the inclusion of ‘filler material’ under the limited combustibility requirement. The only possible logical basis for the Government’s third rationale, that all elements of the cladding system are covered by the requirement, is that all elements other than the two named (‘insulation product’ and ‘filler material’) are to be included in the et cetera. Neither term, ‘filler material’ or ‘etc’, was present in the 2002 version.

It follows that if the Government has effectively abandoned its first rationale, and is relying on the second and third, then it has no basis for claiming that combustible ACM panels on high rise buildings were proscribed under the Linear Route prior to 2007. The 2002 version cannot support these two rationales. It follows further that the Government seems to be claiming in effect that it introduced a ban on combustible ACM panels on high rise buildings under the Linear Route in 2007.

This opens up a fruitful line of historical investigation, which I plan to pursue in the last part of this series. Can the Government produce any evidence that it acted to limit the use of ACM cladding in 2007? Did it at that time make the construction industry and the relevant professions aware of such a change in the regulations? Did industry and building professionals see any new restrictions on ACM panels implicit in the change of wording of the limited combustibility requirement? Or, on the contrary, can evidence be found that there was no such change at that time? Is there evidence that England and Wales in 2007 followed the path taken by Scotland in 2005 when it banned combustible cladding on high rise buildings under the Linear Route? Or is there rather evidence that the disparity between the two systems, which opened up in 2005, continued right up to the terrible night of 14 June 2017?

Andrew Chapman

(Next: Does the Approved Document guidance require all elements of a cladding system to be of limited combustibility?)


  1. These are not actually alternatives. If a material is Euro Class A2, then it is a ‘material of limited combustibility’, as defined in Table A7.
  2. The DCLG itself expresses uncertainty as to whether this is so or not.
  3. In some cases, specified in Section 12.9, the inner surface of the panels may have to satisfy the same requirements. In practice, this is unlikely to add any extra requirement, since normally either the two sides of the panels are the same, or the inner face is uncoated and non-combustible.
  4. Oddly, the less fire resistant PE model was not subjected to BS 476-6 and BS 476-7, the fire tests required for Class 0. But as it achieved a Class B, and this is generally considered to be if anything the harder of the two to achieve, it seems probable that it would have passed the requisite tests.
  5. The diagram is from ‘Walls and Ceilings‘.

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Andrew Chapman

I live for Jesus. He is my life, my hope, my Saviour and Redeemer and Lord. Hallelujah! God has blessed me with a wonderful wife called Alison, and we serve the Lord together with gladness and joy. Pray for us that we may fulfill our calling and persevere to the end on the narrow path that leads to life.

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