Richard North, 28/06/2017  
 


In now what seems a classic over-reaction, we seem to be getting to the stage in the aftermath of the Grenfell Tower fire of having  cladding being stripped off buildings for no good reason.

The immediate points to make are that the Grenfell fire is attributable to a number of factors. For start, it is now known that the tower had a "multicomponent rainscreen cladding system", comprising at its core, Celotex RS5000 polyisocyanurate (PIR) blocks. These were covered by decorative cladding, in this case Reynobond PE.

Of these two products, we have already reported on Reynobond PE and, according to its Agrément Certificate, it passes a Class 0 fire rating under BS 476. In accordance with Building Regulations guidelines Approved Document B1 (Volume 2), it is therefore suitable to use as an external cladding material at all heights – even on high-rise dwelling blocks (see Diagram 40, page 95) – provided it was used within the limits set out in the Agrément Certificate.

However, Celotex RS5000 is a totally different matter. According to the Agrément Certificate to which it links, the product is not classified as non-combustible or of limited combustibility. The Certificate holder has not declared a reaction to fire classification in accordance with BS EN 13501-1.

On this basis, the product is suitable for use without height restriction if installed in a cavity that is between two leaves of masonry at least 75 mm thick. Otherwise, the use of the product is restricted to below 18 metres.

This, as far as the regulations go, is a slam dunk. The product is effectively banned for use in high rise blocks. That, however, does not get Philip Hammond off the hook, or indeed the idiot Marr who put it to him that the "cladding" had been banned elsewhere in Europe. Although Hammond responded by saying that the "inflammable cladding" is also banned in the UK, he is not right.

We are talking here of two different things. The Celotex is insulation and useless without weather protection. The Reynobond is the cladding that provides the protection and the decorative finish. This is the difference between a woolly jumper and a raincoat. They are very different things. Adults should know one from the other – this is just such basic stuff.

Given this situation, though, it could be argued that the European Union is off the hook. Ostensibly, with what appears to be a clear breach of Building Regulations, that is the case. But there are issues here which could have been fatal and still need addressing.

The thing about building construction is that the combustibility of the structure depends not only on the individual performances of the components, but on their behaviour as a system. Cladding will be influenced, not only by the materials used, but by the insertion of insulation, by the extent and nature of any cavities, whether there were adequate fire-stops and whether there are any breaches in the compartmentalisation.

It was that which brought me back into the fray as I continue to explore potential EU involvement, having already published two posts here and here. Before I'd settled the issue on Celotex, I'd already accumulated enough evidence to suggest that the EU had introduced a potentially fatal weakness into our building control system.

To put it together, we have to go back to the year 2000, when the Environment, Transport and Regional Affairs Committee reported on the potential risk of fire spread in buildings via external cladding systems, after a fatal fire in a multi-storey block of flats in Irvine, Ayrshire on 11 June 1999.

Interestingly on the basis of evidence received, the Committee took the view that the majority of the external cladding systems currently in use in the UK did not pose a serious threat to life or property in the event of fire.

At the time (and currently), the standards for external cladding were set out – in the general Building Regulations, and in the Approved Documents. This latter document gave guidance on the interpretation of subjective requirements, such as the need for materials to "adequately resist" the spread of fire.

The ambiguity is removed by reference to official standards, in this case either the European Standard EN13501 or British Standard BS476 (Parts 6/7). The Building Regulation guidance requires the material to pass the BS fire test with a rating of Class 0.

In the 1999/2000 inquiry, though, Peter Field of the Buildings Research Establishment (BRE), complained that the existing guidance was "far from being totally adequate". But the problem was not the standard, per se. The weakness was that it relied on small-scale tests conducted in laboratory conditions. These did not properly evaluate the performance of large, complete, cladding systems in a "live" fire situation.

The Committee accepted that point and recommended a new "Test for assessing the fire performance of external cladding systems", which had been submitted to the British Standards Institution for adoption as a British Standard. This, the Committee said, should be "substituted in Approved Document B for previous requirements relating to the fire safety of external cladding systems".

In its response, the Government accepted the point about testing and promised that as soon as the test had been adopted as a British Standard, the Approved Document would be amended to reflect its status. It was as good as its word.

However, what the Government did not do was implement the specific recommendation of the Committee. It did not replace existing standards with what became BS 8414, introducing a more severe testing regime of a complete structure, set up on a test rig to represent the finished structure.

The reason for that was simple. Under the EU system, currently implemented by Regulation (EU) No 1025/2012 on European standardisation, when a European Standardisation Body (in this case CEN) issued a European Standard, the national bodies had to withdraw any of their standards which conflicted with them – or amend them to bring them into line.

This, the UK's BSI acknowledges, with the details set out in the CEN/CENELEC Internal Regulations, made under the authority of Regulation (EU) No 1025/2012 and Directive (EU) 2015/1535 (replacing Directive 98/34).

Under this system, there is what is known as the "standstill", where the National Standards Body cannot introduce new standards in the areas covered by the European body. This is, in fact, a codification of the "pre-emption" doctrine.

Where this strikes in respect of the cladding testing is that the Commission in 2000 issued Commission Decision 2000/147/EC, implementing Council Directive 89/106/EEC as regards the classification of the reaction to fire performance of construction products. This set out the test procedure in respect of EN13501, effectively locking it in stone.

Known as the Single Burning Item test, to EN13823 – this is a small scale test of exactly the nature Peter Field had complained. But, since the European Standard takes precedence, this means that it had to be allowed under UK law.

We end up with the absurd situation in the guidelines where builders are given the choice between using BS8414, illustrated at the top (right), the test blaze engulfing the test rig, or the very much more modest, material-specific test illustrated on the left.

The choice is very much up to the builder, as contracts of this size must be open to competitive bidding and thus come under the Public Procurement Directive. Bids must be invited, using the European Standards as the basis of the technical specifications. The builders could not be required to adopt the British Standard, which is completely undermined by the cheaper and less rigorous European alternative.

Much is made of the claim that other Member States can adopt their own standards, and they can do so on the same basis that we use BS8414. All other Member States have implemented Regulation (EU) No 1025/2012, and have adopted EN13501, together with EN13823. They may have banned PIR in high rise buildings, but then so have we.

But as of yesterday it was reported d that an 11-storey building in the German city of Wuppertal was being evacuated because it had similar cladding to Grenfell. The Germans, like us, are having to accept lower testing standards to conform with EU rules.

As for Reynobond PE, it was manufactured in France, but marketed globally – and to all countries in Europe. We could, as far as I am aware, strengthen the standard for cladding in the Building Regulations, and thereby exclude it (except that it has already been withdrawn from the market).

For any hike in standards, we would need to get the permission of the European Commission – as long we didn't fall foul of the mutual recognition provisions. But then, as we see, the standard isn't the problem. What we need to do is introduce a more rigorous testing regime, which we are not allowed to do. The only thing we can do is lobby Brussels to improve the EN.

In the particular instance of Grenfell Tower, though, we cannot say that the inferior European standard was a direct factor in this fire. But it can be said that if BS8414 had been a mandatory requirement, and enforced in the refurbishment contract, that particular construction would not have been approved and the fire could not have happened.

This stands as a reminder that in some areas we are still ahead of the game, and that there are good things to come out of Brexit. But the irony is that, on our withdrawal, we have the opportunity to tighten up our rules and make them stick. So much for the bonfire of regulation.






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