9. Witnesses to our inquiry (including the Fire Brigades Union,[30] the Loss Prevention Council (technical advisers to the insurance industry),[31] manufacturers of external cladding systems,[32] and independent fire safety consultants[33]) suggested that the guidance given in Approved Document B may not be adequate for the purposes of ensuring the safety of external cladding systems in a fire. We were also told in oral evidence by Peter Field of the Buildings Research Establishment, which has done a great deal of work on these issues, that the existing guidance "is far from being totally adequate".[34]



10. Witnesses' chief concerns lay with the risk of unexpectedly rapid fire spread involving these systems, which, it was suggested, may have a number of adverse consequences of which the existing guidance does not necessarily take full account. These are:



shorter period available for escape from the building, thus potentially endangering life;[35]

disproportionate difficulties in firefighting;[36]

disproportionate damage to the building.[37]

11. Witnesses also raised a number of other potential problems of which existing tests may not take proper account:



the fixtures which attach the cladding to the building may not withstand the fire, risking the detachment of the system from the building and endangering persons in and around the building, including firefighters;[38]

if plastic materials are used for the cladding, they could melt and form burning droplets which again endanger people below;[39]

certain materials could degrade over time and become less resistant to flame spread than they were at the time of construction.[40]

12. Witnesses' complaints about the adequacy of the guidance focus on the methods of testing a material for resistance to fire spread. The classifications 'limited combustibility' and 'Class O' referred to in Approved Document B rely on small-scale tests conducted in laboratory conditions. It was suggested that these tests do not properly evaluate the performance of large, complete, cladding systems in a 'live' fire situation.[41]



13. Concerns about the fire safety of external cladding systems are not new. A fire which occurred in a tower block in Knowsley in 1991 was started at ground floor level and spread up 11 floors behind 'rainscreen' cladding. The inquiry which followed this fire resulted in a change to Approved Document B which provided for the requirements for 'Class O' material to be used on both the inside and outside of external cladding, and to include 'fire stopping' in the gap between the cladding and the wall of the building (see (d) and (e) in paragraph 7 above).



14. The inquiry also prompted further research at the Fire Research Station of the Buildings Research Establishment (BRE). The conclusions arising from this research, which was carried out in 1994, support the claims of our witnesses that the small-scale tests upon which existing guidance relies are insufficient properly to evaluate the performance of complete cladding systems in a fire, and that there is therefore a clear need for full-scale testing.[42]





15. BRE proceeded to develop an appropriate full-scale fire test, known as 'A test for assessing the fire performance of external cladding systems'.[43] This test was submitted to the DETR in 1996.[44] Witnesses suggested that this test would be a considerable improvement on the small-scale testing which is currently carried out to ascertain the fire performance of materials used in external cladding systems.[45]



16. Other witnesses suggested that this test would not be suitable for all external cladding systems, and in particular that it would not be a suitable method of testing the fire performance of 'infill' systems such as that which was involved in the fire at Irvine.[46] However, we note the view of Peter Field of BRE, which developed the test, who told us, "We believe the test facility itself could be accommodated to assess the fire performance of systems which are not the same as total cladding systems and may involve windows and decorative panels"[47]. The advice we have received concurs with this opinion.



17. The DETR told us in written evidence that this test will be referenced in Approved Document B, and that it was intended that it become a British Standard.[48] However, such reference does not amount to a requirement that cladding systems pass the test: simply that the test is one way of ensuring that the system meets the requirements of the Building Regulations.

