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  1. Thanks for the enormous effort you\’ve put into this, Andrew. Really interesting, with a horrifying conclusion

  2. Andrew. Good man! Where is Parts 1 and 2? Can we please email to consolidate this into a simpler text? Regards, Ian Abley.

  3. This 3 part blog has the best coverage I have seen of the technical issues and the plethora of standards relating to the fire performance of the cladding panels.

    Whilst the evidence presented suggests that the Celotex insulation and the core of the Reynobond ACP facing would combust at the point of fire entry, there may be a (remote) possibility that if the panel had remained intact and the perimeter firebreaks had remained effective then the fire might have been contained within the panel – this would seem to be the basis of allowing a fire test of a representative assembly (as undertaken for a different Celotex based construction) to show compliance by performance. The specification and installation of the firebreaks on the Tower will be evident on the remaining cladding to the lower portion of the building .

    The weaknesses of the \’fire test performance of an assembly\’ approach are a) the allowing of a desk based assessment of the fire performance of variations by a competent person – to avoid the the cost of more testing and b) the short period of time that the test requires the assembly to limit fire spread.

  4. Thanks, Jim, for the kind words. Another drawback of the system fire test approach, it seems to me, is that the detailing will no doubt be done very carefully for the test, whereas we cannot be sure that it will always be done so well in real life.

    With regard to the time period, the fire burns for half an hour in the test, which I would have thought should be just about enough time for the fire to be put out, even if it’s on an upper floor of a high building.

    I agree with you about desktop testing, especially in the light of what has emerged about some of the systems that have been passed through desktop studies (even with FR ACM), apparently without any very closely related system being subject to a live fire test. But this weakness is not inherent to system testing, of course – the regulators are under no obligation to allow it at all.


  5. Yes, excellent job of digging. The information certainly does provide a good overview of the product properties. But be careful, Class 0 is a class used in Approved Document B, not derived from British standards. It refers to surface spread of flame – the surface – ref Diagram 40 and 12.6 in AD B. That isn’t the same as combustibility, which is bulk property of the whole material.

  6. Thanks, Mike. I am at a bit of loss to understand why you think I might not be distinguishing properly between Class 0 and limited combustibility. I summarised the Linear Route above as follows:

    ‘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.’

    Does that not make the distinction between the two very clear?


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