Month: June 2017

Grenfell Tower: was the cladding legal or not? (part 3)

In my previous two posts (part 1, part 2) I have outlined the two routes offered by the Building Regulations 2010 Approved Document B (Vol. 2) at B4 (‘External Fire Spread’) to meet the statutory requirement that:

The external walls of the building shall adequately resist the spread of fire over the walls…

The first route, also sometimes called Option 1, or the ‘linear option’, is to satisfy the requirements of paragraphs 12.6 to 12.9. With regard to the fire properties of materials used in cladding systems for buildings over 18m in height, the requirements are in brief:

a) 12.6. External surfaces should be UK Class 0 OR European Class B or better. The relevant UK tests are BS 476-7 and BS 476-6. The European tests are EN ISO 11925-2 and EN 13823. All four tests are surface tests.

b) 12.7 Insulation products should be of ‘limited combustibility’. They should pass EITHER the BS 476-11 750º C furnace test OR the EN ISO 1182 750º C furnace test OR the EN ISO 1716 calorific test. These are combustibility tests.

The second route, also sometimes called Option 2, is for the entire cladding system to pass a large-scale test to BS 8414.

I will now describe the fire properties of the main two components used in the cladding system at Grenfell Tower, and discuss whether they could satisfy the Approved Document B4 requirements, through either of these two routes.

Continue reading Grenfell Tower: was the cladding legal or not? (part 3)

Grenfell Tower: was the cladding legal or not? (part 2)

In my last post, I pointed out the statutory requirement, contained in Article B4(1) of Schedule 1 of The Building Regulations 2010, that:

The external walls of the building shall adequately resist the spread of fire over the walls…

I then began to examine the guidance given by the government in Approved Document, Volume 2, at the corresponding part B4, as to how this statutory requirement can be met. Two alternative routes to compliance are given in Section 12.5:

In my last post also, I examined the provisions of paragraphs 12.6 to 12.9 and in particular of 12.6 and 12.7 which concern the fire properties of the materials used in construction. I explained that, for buildings over 18m high:

a) The requirement of 12.6 can be satisfied if the materials are UK Class 0. This classification can be achieved through satisfactory performance in two UK fire tests, BS 476 part 7 ‘Surface Spread of Flame’; and part 6 ‘Fire Propagation’. In both of these it is the surface of the board or panel that is subjected to assault by fire.

b) The requirements of 12.7 appear to apply to insulation products only.  The materials must either survive trial by a furnace at 750° C, or have a calorific value of less than 3 MJ/kg. I argue that no material with a substantial component of a polymer like the PIR of the Celotex boards, or the PE of the Reynobond panels, could possibly pass these tests.

In this post I describe the BS 8414 fire test, which is offered as an alternative route to compliance at paragraph 12.5. In following posts I plan to:

Continue reading Grenfell Tower: was the cladding legal or not? (part 2)

Grenfell Tower: was the cladding legal or not? (part 1)


Philip Hammond, the Chancellor, claimed on the Andrew Marr Show on 18 June 2017 that the cladding that was used on Grenfell tower is banned in the UK:

[17 JANUARY 2018. THIS PARAGRAPH REPLACES THE TEXT OF JUNE 2017.

Was he right? If he was referring to the aluminium composite cladding panels, then he was not. Under the official Approved Document guidance, commonly known as the building regulations, the ACM panels used on Grenfell Tower possessed the requisite fire performance certification. This does not mean that they were safe. On the contrary, aluminium composite panels with a polyethylene core are highly combustible and should never be used on high buildings.

END OF NEW PARAGRAPH.]

Continue reading Grenfell Tower: was the cladding legal or not? (part 1)