Philip Hammond says his ‘understanding’ is that material should not have clad tower - and will be focus of criminal probe

The use of the type of cladding used to cover the Grenfell Tower in Kensington is banned in the UK, according to the chancellor, Philip Hammond.

Speaking on yesterday’s Andrew Marr programme on the BBC, Hammond was asked if the government would pick up the tab for replacing such material currently cladding tower blocks across the UK, if it were found to have been used.

Hammond ducked the question, instead saying he believed the material was banned here.

“My understanding is that this material, which is banned in Europe and banned in the US, is also banned here.

“There are two questions around this. Are our regulations correct? Do they permit the right kind of materials and ban the wrong sort of materials?

“And secondly, were they correctly complied with? Obviously that will be a subject the [public] inquiry will look at. It will also be a subject the criminal investigation will be looking at.”

The prime minister Theresa May faces mounting criticism over the government’s response to the disaster, which has so far known to have claimed nearly 60 lives. The local Conservative-led council has also been taken to task for not providing enough support for surviving victims of last week’s blaze and has now had its responsibilities taken over by central government’s Gold Command.

Thomas Lane, editor of Building Design, writes:

Reynobond is not banned in the UK. It has a BBA certificate which includes details of the panel’s compliance with European and British fire standards and Arconic, the manufacturer of Reynobond publish the fire ratings in its technical guidance.

Reynobond PE, the panel which features a polyethylene core has been tested according to the standards set out in BS EN 13501-1: Fire classification of construction products and building elements. According to the certificate the panels have a Class 0 rating for the surface spread of flame which is the highest rating. The certificate also says the polyethylene cored panel has a reaction to fire classification of B –s2 and the fire retardant version a rating of B –s1. This contradicts Reynobond’s fire certification documentation which states the fire retardant version of the panel has an A2 rating. The highest ‘A’ rating requires materials to be non-combustible and an ‘F’ rated material is easily flammable. The polyethylene cored Reynobond panel is regarded by BS EN 13501-1 as being combustible with very limited contribution to fire.

According to Part B, the building regulation which deals with fire safety, the external envelope of a building should not provide a medium for fire spread if it is likely to be a risk to health and safety. Any insulation product or filler material used in the external wall construction of a building over 18m tall should be of limited combustibility. A table in Part B, diagram 40 shows what classification of material can be used in different parts of a building. It states that materials with a classification of class C-s3 – combustible with a limited contribution to fire - can be used in buildings up to 18m tall. A building over 18m tall must use materials with a classification of B-s3 or better. This suggests both types of Reynobond panel would meet the requirements of Part B for the flammability of external cladding.

There appears to be a contradiction in Part B. Table A7 in the appendix defines materials of limited combustibility which must be used on buildings over 18m tall. This states a material tested to BS EN 13501-1 must have a rating of A2 – s3 or better, in other words non-combustible. According to the BBA certificate neither of Reynobond’s panels would meeet this requirement. Arconic’s own documentation states that the fire retardant version would have been compliant with this requirement but not the polyethylene cored panel.