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complex as air must flow for ventilation and drying, so can’t be sealed. Dr Glockling showed examples of how intumescent protection should work. However, these products are said even by their
Testing was not about the structure but
the interrelation of combustible materials, this method of construction ‘infer[ring] a system of encapsulation’ with combustible materials behind higher performing materials. The tests aimed to ask if methodology was ‘accurate to real life’, as the world ‘is not perfect and things change over time’, with this ‘difficult to quantify’ in BS 8414. Aims included to understand the realism of the
fire challenge, the issues surrounding installation of vents that breach cladding, the installation of provision for oxygen flow, the performance of cavity barriers, and the realism of the installation. On the first element, BS 8414 uses a wooden crib, but Dr Glockling asked if this was really ‘representative of the modern day’, and the FPA test used 20% of plastic, which provided a longer fire plume, a more rapid take off and a higher temperature. There were ‘questions to be asked’ about using wood, especially given that insurer tests have used fully recreated offices and found that fuel loads have an impact on testing. Looking at breaches, BS 8414 does not feature
fire stopped or non fire stopped breaches (there being no requirement for the latter), but voids could provide a route for fire spread. FPA tests reproduced timber frame and ETICS rigs featuring vents, fires started by wheelie bins, with even a non combustible material test allowing fire in through voids, allowing the passage of fire in and providing a ‘direct flame attack’ on combustible materials. As fire needs oxygen to spread, a small rig was
developed to show how voids can impact this. One rig with no void saw fire ‘reluctant to climb’, while a sealed rig saw the fire extinguish itself; but the rig with a void saw fire quickly spread up. On cavity barriers, these elements make the void area
48 JULY/AUGUST 2018
www.frmjournal.com
manufacturers to ‘technically fail’, and there were questions about the testing methods, with the FPA test showing such a barrier did not activate until flames had passed it up the void. Finally, on real life detailing, Dr Glockling noted that you have to ‘ensure that what’s tested is identical to the end use of the building’, referencing use of desktop studies and noting that design details can and do change during construction. With the testing procedure stating certain set ups and specific details, it does not however fully take into account the interrelation between cladding and windows, the FPA testing two set ups including a perfect build as outlined in BS 8414. Both tests failed, and Dr Glockling made it clear that the programme was not criticising the laboratories undertaking the tests, but the relevance of the tests themselves. He questioned if tests could be deemed
appropriate when taking voids and recesses into account, as these are real life elements that caused failures when included. Making the case for non combustibility, he noted that built up testing is complex if including real world challenges, with non combustible materials reducing susceptibility to all issues, though ‘what is non combustible’ depends on the scale of the fire challenge. With four basic types of material ranging from those that easily ignite and stay on fire through to those that don’t and don’t contribute to fire, some experiments can end up causing confusion due to different performances and abilities of materials when interrelating with one another. As a consequence of the FPA programme, the British Standards Institution is reviewing BS 8414.
Construction products
Andrew Taylor of the Association for Specialist Fire Protection cited the leaked BRE report into Grenfell, which had illustrated product failures in the cladding, doors and window finishing corresponding to incorrect specification, use and installation. Analysing the Hackitt report, he pointed out that its focus on products includes recommendations for third party certification, regular auditing and certification of products, better testing and less use of desktop studies. Dame Judith’s report also called for a clearer
certification process and an identification of the scope of certification, more traceability for products and use of digital technology. Asking ‘where are we today?’, he noted that testing and certification is complex ‘but necessary’, with the latter ‘difficult to understand’ for the construction industry.
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