鈥機lass 0鈥� rating was used for external walls until 2018 despite being based on how fire behaves indoors
The government official responsible for fire safety in buildings had not questioned flawed fire ratings for cladding before the Grenfell Tower disaster, the inquiry into the 2017 blaze was told yesterday.
Brian Martin said he did not think he had 鈥渃onsidered鈥� that the Class 0 rating, which is based on how fire behaves indoors, might have been an 鈥渋nappropriate鈥� way to judge the fire safety of external walls.
The UK Class 0 rating was used in government guidance to mark a cladding system as safe until December 2018, when it was removed in the wake of the fire at Grenfell Tower.
But the specification is based on two testing regimes for internal walls and ceilings. It also focused on how fire spreads across the surface of materials, meaning that products which contained combustible cores 鈥搒uch as the highly combustible ACM cladding used on Grenfell Tower 鈥搘ere sometimes able to obtain the rating.
Martin, who had responsibility for fire safety guidance at the Department for Communities and Local Government from 2008 to 2017 despite having no formal training in the field, was questioned at yesterday鈥檚 hearing about the government鈥檚 use of Class 0.
Counsel to the Inquiry Richard Millett QC asked him: 鈥淒id it ever occur to you鈥� that [Class 0] are inapposite tests for an external wall, given their origins?鈥�
Martin replied: 鈥淚 don鈥檛 think I had considered that before Grenfell Tower.鈥�
He was also asked about the suitability of the Euroclass B rating, which was used alongside Class 0 to assess the safety of cladding from 2002. The European standard, although tougher to achieve than Class 0, was largely based on a 鈥漴oom corner test鈥� - in this case a burning waste paper bin in the corner of a room.
Millett asked Martin whether he ever had 鈥渃ause to consider whether that test [the room corner test] was useful for assessing fire behaviour in circumstances far removed from that scenario, namely on the external face of a high鈭抮ise building?鈥�
Martin said it was 鈥済enerically鈥� a subject that I was aware of, not specifically in relation to external walls鈥�. He added: 鈥淭he tests get used in a wide range of applications, many of which are not directly comparable to an internal wall lining.鈥�
Pressed on whether he had considered whether Euroclass B was an appropriate test for external walls, he said: 鈥淚 don鈥檛 think I did.鈥�
Martin was also questioned about the government鈥檚 response to the 1999 Garnock Court fire in Irvine, Scotland, which destroyed flats across nine floors of a 14-storey residential block after the building鈥檚 combustible cladding caught fire. Martin was a member of a team of researchers from the 黑洞社区 Research Establishment (BRE) investigating the fire.
He co-authored a report for North Ayrshire council which said that, although the cladding material used on the building 鈥渟hould have been Class 0, we have reservations about its current performance鈥�.
It added: 鈥漌e suggest that non-combustible materials are chosen wherever possible.鈥�
This was followed by a December 1999 report on the dangers of cladding fires by a group of MPs which called for the Class 0 rating to be replaced by a requirement that cladding systems be either 鈥渆ntirely non-combustible鈥� or pass a new BRE fire test.
However, the government did not follow the recommendation in an April 2000 revision of building fire safety guidance and chose to keep the Class 0 rating.
In August of that year, the BRE delivered a second report on the Garnock Court fire which was largely identical to the first, except that the advice on using non-combustible materials had been removed. All references to Class 0 in the report had also been removed.
Asked if the references to Class 0 had been removed 鈥渁t the request of the department鈥�, Martin said: 鈥淣ot that I鈥檓 aware of.鈥�
Millett then asked: 鈥淒o you accept that the only explanation for those excisions is that somebody was told to excise them in order to make the BRE鈥檚 report to government in 2000 about Garnock Court consistent with the government鈥檚 earlier decision to reject the select committee鈥檚 recommendation?鈥�
Martin replied: 鈥淚 don鈥檛 know for sure because I wouldn鈥檛 have been involved in that conversation. But I find that hard to believe.鈥�
But asked if he could provide an explanation for why the report had been changed, he admitted: 鈥淚t does seem odd. I can鈥檛 think of a good reason for it.鈥�
Martin was also asked why the Class 0 rating had not been looked at again until a 2006 revision of fire safety guidance. He said: 鈥淚 think we just considered it as water under the bridge.
鈥淚t sounds really glib, and I鈥檓 sorry, but that鈥檚 - those were decisions that had been made and so, unless there was a driver to revisit them, it didn鈥檛 come up.鈥�
The inquiry continues.
