Thread by @AndrewChapman50

Thread on the #GrenfellCoverup. By a grotesque post-Grenfell reinterpretation of the Approved Document guidance, the government has been seeking to evade its responsibility for the fire and put the blame on others. Labour, who share approximately equal responsibility from 1/

their time in government, especially from 1999-2010, are complicit in the cover-up. The essence of the matter is that combustible cladding on high rise was always allowed in the national building regulations from their inception in 1965 until 18 June 2017, 4 days after Grenfell,

when @dawes_melanie, Permanent Secretary at @mhclg, in a letter to Local Authority and Housing Association Chief Executives, claimed that Building Regulations guidance required the ACM core to be of 'limited combustibility': assets.publishing.service.gov.uk/government/upl…

The combustibility of such materials, as defined in the guidance (at AD B2, Table A7), is so low that it has been considered acceptable for Scotland to use the term 'non-combustible' for virtually the same category.

Dawes had been advised by an Expert Group which had met the day before at the DCLG offices in Marsham Street: assets.grenfelltowerinquiry.org.uk/documents/3.%2…

and had claimed that of the 3 types of ACM on the market [PE (used on Grenfell), FR (fire retardant), A2 (Euro Class A2)], the use on high rise of only one [A2] was compliant with the Approved Document guidance:

The limited combustibility requirement was to be found at para 12.7 of Approved Document B2, under the heading 'Insulation Materials/Products': assets.publishing.service.gov.uk/government/upl…

Obviously, it applies to insulation materials and products. In her Expert Report to the @grenfellinquiry Dr Barbara Lane said she had 'no understanding why it applies to anything else'. Quite.

assets.grenfelltowerinquiry.org.uk/documents/Dr%2…

The outer cladding material of a rain screen system does not serve an insulation function for the simple reason that the cavity behind it is ventilated, so that cold air can pass behind it: wconline.com/blogs/14-walls…

For a formal statement of this simple point, Lane references British Standard 8298-4 for stone based rain screen cladding. The air gap is assumed to be well ventilated, so that the rain screen can be assumed to have no effect on heat loss:

and she concludes that an Aluminium Composite Product rain screen cladding layer is not an insulation material or product:

Nevertheless, in a further letter to the Chief Executives on 22 June, @dawes_melanie claimed in a footnote that, 'for the avoidance of doubt', the ACM core *might* be an insulation material/product as referred to in AD B2 12.7: assets.publishing.service.gov.uk/government/upl…

But then again, it might *not* be, since the 'and/or' allows for the possibility of the ACM core being a 'filler material' and not an insulation material/product.

Likewise, the ACM core *might* be a filler material; but again, it might *not* be, since it might be an insulation

material/product. Now, if @mhclg was uncertain whether the ACM core is insulation, and uncertain whether it is filler, how can it be certain that it is one or the other or both ('and/or') rather than neither?

And it should be recalled that this document which DCLG was struggling

to interpret was produced by none other than the DCLG, as explained to the Lakanal Inquest by the relevant official Brian Martin in 2013: lambeth.gov.uk/sites/default/…

How could it be that @mhclg were unsure of the meaning of the text they had written? Answer: they knew exactly

what it meant, but didn't want to admit that they had failed to stop the use of the highly dangerous PE ACM panels on high rise, despite a) the recommendations of the 1999 ETRA Committee, which the Labour government failed to follow; b) the example of Scotland, which acted to

stop the use of such materials on residential high rise in 2005; c) the spate of high profile PE ACM fires, especially from 2012 onwards, in France, Dubai and elsewhere.

With regard to the alternative possibility, that the ACM core is a 'filler material', required under AD B2

12.7 to be of 'limited combustibility', Dr Lane acknowledged the existence of the claim, but disagreed with it, giving her reasons in some detail:

In February 2018 I conducted searches in technical literature for examples of the ACM core being referred to as 'filler' or 'filler material', failed to find any, and challenged the government to produce a single example of such usage in the public domain: theriveroflife.com/2018/02/08/gre…

I also investigated what 'filler material' *does* mean in the construction industry, and concluded that the term is employed to refer to materials such as polyurethane foam which are used to fill gaps and cavities around windows, penetrations, and so on: theriveroflife.com/2018/02/21/gre…

On 10 May 2018, David Metcalfe and Dr Stephen Ledbetter, the present and former Directors of the Centre for Window and Cladding Technology, based at the University of Bath, in a letter to Clive Betts MP, the chair of the HCLG Committee, said that Brian Martin the above named

DCLG official had told them that the term 'filler material' had been introduced into the 2006 edition of AD B to prevent 'the overuse of can-applied foam and similar materials to fill gaps within the façade': parliament.uk/documents/comm…

This important evidence from Metcalfe and Ledbetter must be heard by @grenfellinquiry, and by @metpoliceuk. Where are the arrests, and where are the prosecutions? @GrenfellUnited