I will detail some of the work that we have done on BS 8414 testing. I thank the committee for giving me the opportunity to give evidence.
Since Grenfell, between the ABI, RISCAuthority and the FPA, insurers have contributed the best part of £0.5 million in order to understand better the standards that are used to authenticate the material that is used on buildings. Their reasons for doing so are perhaps slightly different from those of others. Insurers need clarity when they are determining what the estimated maximum loss might be in any given building. Fire is a unique peril in that it has the capability to exceed those limits very quickly if nasty surprises arise.
The work that we have done is very independent—we took a fresh-eyes look at the standards, with no remit. Insurers would love us to say that there is no problem, rather than that there might be a problem. We conducted many tests on the BS 8414 scale and looked at its capability to assure fire performance from an insurance perspective. We concluded that although it is a better test than many others out there, development is needed in order to meet that remit.
The research continued and we found a discontinuity in the building regulations, as they currently stand, between the fire-stopping requirement relating to the external envelope of the building and the toxic hazard that can be presented to occupants from fires in the cladding void. We feel that further work is required to ensure that there is appropriate separation of occupants from the toxic hazard that can be generated.
The key point is that BS 8414 is not a bad test, but it is not developed enough to ensure that real life can be replicated. It is possible that, following a failure, rather than different materials being selected, certain rearrangements of materials could be carried out to allow such a test to be passed. That suggests that design detailing is critical to performance. We need to ask ourselves—this echoes what other witnesses have said—whether those details are realistic and practical, and whether they represent what goes on the building.
To summarise, I say that the BS 8414 testing has been used as a test of materials rather than a test of system. It is usually commissioned by product manufacturers rather than by the end user or specifier. As such, important materials such as membranes are often omitted from tests. We know that things such as vapour membranes can spread fire more quickly than cavity barriers can respond, and we feel that that is important. Important features such as the presence of plastic ducts and vents are also omitted from the tests, which do not have to be fire stopped on the external envelope of the building. I will say more about that later.
In addition, the scale of the test is somewhat wrong, in that the fire is the same width as the façade specimen, so that can lead to the void being preferentially sealed against air flow in the void from the void, which would not be the case in a much larger building with a broader footprint.
Test installations can end up being overrobust, oversimplified and oversealed, and can therefore result in an overfavourable outcome. A lot of the problem is to do with realism. We test many systems in our laboratories. Currently, all our rigs are tied up looking at current buildings and assessing whether what is on them is okay. Just today, I was heartened to learn of a request being made—I do not know whether it was by the building owner or the local authority on whose behalf the test was being done—for the whole system to be removed and put back on properly so that it correctly mirrors the building. That is heading in the right direction.
I will finish off by mentioning a key feature that I think is missed in all the testing. The presence of plastic ducts and vents does not form part of a fire test. Those are not fire-stop devices, but they form a route for fire ingress and fire egress from a building. That is not considered. As a result, a key feature that we are seeing is many buildings are susceptible to fire ingress straight into the void, where there might be combustible structures or combustible insulation.
That sums up the research that we have done to date and our criticisms. I entirely agree that tests that were honestly used are at the root of many of the problems. However, at the end of the day there are also key issues with scale and how testing is conducted.