The Fire Protection Association (FPA) has today published a report detailing initial research that is designed to help the government in its deliberations on the acceptability of combustible building materials.
A decision on the future use of combustible materials in the construction of buildings is expected from the Ministry of Housing imminently.
The FPA report investigated the effects of toxic fumes generated by certain cladding combinations in designs that are still permitted by building regulations – and the effect this has on the people occupying buildings when fire breaks out.
FPA technical director Jim Glockling explained: “Measuring smoke toxicity in building products is currently not a legal requirement. The results of our study show that current regulations may not adequately protect occupants from the potentially toxic fire gases from materials burning on the outside of buildings. Some current common cladding material combinations were shown to present less of a threat than others. There is certainly a need for further study.”
A key feature of rain-screen cladding (the type used on Grenfell Tower) is a space formed between the insulation material and the back of the cladding panel that may also contain other materials such as vapour membranes (a sheet of material to keep out moisture). There are clear rules governing how the internal walls of a building must contain fire to assist with safe evacuation, but few requirements stipulating how external walls should prevent the spread of flame and heat from outside. Devices and features such as bathroom or kitchen vents have the potential to transmit fire and smoke from the cladding system into the occupied space.
The FPA report confirms a potential for serious harm to any human exposed to these toxic products in the event of a fire. The results looked at a typical living room in a building covered in a rain-screen type cladding. The findings suggest that for some compliant material combinations, once the fire breaks into the cladding section containing a vent connected to their apartment, occupants will lose consciousness within 10 minutes and, unless rescued, will die within 30 minutes.
The Fire Protection Association’s testing, conducted at its laboratory in Blockley, Gloucestershire, involved a selection of cladding and insulation combinations legitimately used on buildings in the UK, including similar materials to those used on Grenfell Tower. Four tests were conducted and compared the potential contribution from smoke toxicity that might be made by different cladding and insulation configurations.
The FPA is offering this work to government and the Grenfell Inquiry to assist in future discussions on the merits of the specification of non-combustible materials in buildings, and the need to strengthen regulations in respect of fire and smoke ingress. It says that – at the very least – its work should prompt further research into whether the evaluation of fire toxicity should become an integral part of the building products approval process.
FPA managing director Jonathan O’Neill said: “This work reinforces our view that a range of factors, such as measurement of toxic fumes, need to be considered when choosing building materials, in order to protect buildings and ultimately save lives. The Fire Protection Association wants assurance from government that systems are in place to regularly review building standards to ensure that the UK can never experience a tragedy on the scale we witnessed at Grenfell – on our or any future generations’ watch.”
The FPA research was funded by the UK insurance industry through RISCAuthority. The University of Central Lancashire assisted with toxicant analysis and consulting engineer Arup contributed material design detailing.
The full report is available on the FPA's website or by clicking here.
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