Celotex, which makes the RS5000 insulation used in the rainscreen cladding system on Grenfell Tower’s 2016 refurbishment, made the revelations in its opening submission to Phase 2 of the Grenfell Tower Inquiry
It said: “Studio E, Harley, Exova and Rydon all appear to have known that the panels would fail in the event of a fire where external flaming occurred. This is clear from an exchange of emails involving these entities in March 2015 arising out of a debate with Building Control about whether cavity barriers or fire-stops were required in the rainscreen cavity.”
Studio E was the architect, Rydon the main contractor, Harley the cladding subcontractor and Exova the fire safety consultant.
To quote directly from Celotex’s submission:
In an email on 27 March 2015, Mr Anketell-Jones (Harley) said to his colleague Ray Bailey that: "there is no point in 'fire stopping', as we all know; the ACM will be gone rather quickly in a fire! The whole point is to stop 'unseen 'fire spreading in the cavity .."
In an email to Mr Crawford (Studio E) on 31 March 2015, Mr Ashton (Exova) told Mr Crawford that: "it is difficult to see how a fire-stop would stay in place in the event of a fire where external flaming occurred as this would cause the zinc cladding to fail”
In response to Mr Ash ton's email, Mr Crawford told Mr Ashton that: "this was my point as well - metal cladding always burns and falls off, hence fire stopping is usually just to the back of the cladding line"
In an internal email on 31 March 2015 to Mr Ashton, Mr Pearson (also of Exova) expressed the same point in the following terms: "if significant flames are ejected from the windows, this would lead to failure of the cladding system, with the external surface falling away and exposing the cavity, eliminating the potential for unseen fire spread."
Mr Crawford forwarded Mr Ashton's email (stating that the cladding would fail in the event of a fire where external flaming occurred) to Mr Lawrence (Rydon). Mr Crawford explained that Mr Ashton's email set out Exova's response on the cavity barrier / fire-stop debate and that no-one agreed with Building Control. Mr Lawrence responded: "Excellent. That looks positive."
Celotex goes on to say: “Whilst expressed in slightly different terms, the substance of what each of Harley, Studio E, Exova and Rydon was openly acknowledging in the above emails was that the cladding would fail in the event of a fire with external flaming.
“None of the individuals involved in the March 2015 email exchange have sought to explain how their knowledge that the cladding would fail in the event of a fire with external flaming can be reconciled with their responsibility as designers, contractors or consultants (as the case may be) to ensure, or exercise reasonable care to ensure, that the rainscreen cladding system on Grenfell Tower complied with Requirement B4(1). It is currently unclear whether those matters can in fact be reconciled."
Celotex’s full 51-page submission can be found at grenfelltowerinquiry.org.uk