Fire safety reform is needed to keep UK homes and commercial premises safe, says report
Fundamental reform is needed to keep homes and commercial premises safe from fire in the UK after a series of carefully controlled tests found that blazes can burn hotter than currently thought.
Research conducted on behalf of the insurance industry in the wake of the Grenfell Tower fire in London in which 71 died has exposed the ‘utter inadequacy’ of the laboratory tests currently used to check the fire safety of building materials.
The Association of British Insurers (ABI) commissioned the Fire Protection Association (FPA) to carry out a series of carefully controlled experiments recreating more realistic building conditions than those in which the standard tests are done, in an effort to measure what difference these factors could make in the event of a fire.
This comes as landlords of tower blocks are waiting on the outcome of the official review by Dame Judith Hackitt into the Grenfell Tower in which cladding is thought to have played a part in the fire spreading so quickly.
The FPA report says that a number of real-life factors are overlooked by the official testing regime including the fact that test fires are only made up of wood whereas in modern blazes, around 20% of the materials involved are plastic.
It also highlights that cladding materials are sometimes tested as a sealed unit, whereas when fitted on a building they often include gaps, and cover a far more extensive area. It adds that materials tested will be in manufacturer condition, but during their actual use will often be pierced by things such as vents or ducts.
In its submission to the official review, the ABI calls for an end to the use of all but non-combustible materials in construction and a reformed testing regime that replicates real world conditions to provide genuine evidence of how materials perform in a fire.
The results of these latest tests all reinforce the importance of urgent reform, according to Huw Evans, director general of the ABI. ‘Dame Judith Hackitt’s important work post-Grenfell has already recognised the building control system is broken,’ he said.
‘This latest research is yet more evidence that fundamental reform is needed to keep our homes and commercial premises safe from fire. It is a matter of urgency that we create the right testing regime that properly replicates real world conditions and keeps pace with building innovation and modern design,’ he added.
The FPA tests involved creating two fires with the same energy content, one purely built out of wood, the other containing 20% plastic. The flames created by the fire containing plastic had a flame length around one metre longer than the wooden fire and the temperatures involved were 100 degrees hotter and still increasing when the plastic-containing fire had to be extinguished because it was exceeding lab safety conditions.
‘As well as the ability of the fire containing plastic to spread faster and create higher temperatures, building materials such as aluminium lose a lot of their strength at higher temperatures. A lot of cladding, including that used on Grenfell Tower, is made up of aluminium composite panels,’ the report points out.
In a second test fires were started at the bottom of three columns. One had no cladding or cover at all, the second had cladding fitted to create a void but with sealed edges and ends, the third was clad with a void, leaky sides and some ventilation at the top and bottom.
They found the fire climbed 1.5 metres up the open face before burning out and self-extinguishing and the sealed cladding unit also saw fire climb a similar distance before it ran out of oxygen and self-extinguished. The unit where the cladding had gaps rapidly caught fire up the entire six metre height of the testing column.
‘The availability of oxygen makes a massive difference to how materials respond to fire. In well-ventilated voids, such as behind some cladding systems, the rate at which fire spreads can be greatly increased by a chimney effect. Any tests which restrict the availability of oxygen in a way that doesn’t happen on a full scale building will not be able to correctly assess how the materials will behave in practice,’ the report explains.
In a third test a section of wall and cladding was set up with a plastic vent installed and a fire started beneath the structure. Temperatures inside the vent indicated it was providing an almost instantaneous route for fire directly into the void between the wall and cladding, long before the time it would take fire to break through the outside cladding panels.
‘Fire safety, particularly in high rise buildings, often relies upon assumptions about how long it will take fire to penetrate certain areas of the building. The presence of fittings such as vents can make a big difference to how materials perform and how a fire will spread, and needs to be realistically modelled in testing,’ the report adds.
‘The results of this important research confirm long-held concerns by many in the fire sector that the current cladding test standard requires urgent review to ensure that systems that pass are reflective of the systems that are installed and of the risks to which they are exposed,’ said Jonathan O’Neill, managing director of the Fire Protection Association.
‘We urge BSI (British Standards Institution) to urgently reconvene the group responsible for this standard to consider the results of this research and to make changes to the standard as required,’ he added.
In a statement, the Ministry of Housing, Communities and Local Government (MHCLG), said that the current British Standard 8414 test is a robust test. ‘The BS 8414 requires that a wall with a complete cladding system, including panels and insulation, fixed to it, is then subject to a fire that replicates a severe fire in a flat breaking out of a window and whether it then spreads up the outside wall,’ it said.
‘The Independent Expert Panel stand by the earlier advice issued by MHCLG, following their consideration of the Government commissioned tests over Summer 2017. Building owners should take their own professional advice on any further action, with regard to their cladding system, reflecting their own particular circumstances.
‘Where panels are removed for inspection or testing purposes, the integrity of the whole cladding system needs to be maintained. The structural design of any replacement cladding needs to be checked – it should not be assumed that existing fixings and systems are suitable for replacement systems.
‘The need to ensure that replacement cladding systems or components protect the building adequately from rain and condensation. The Independent Expert Panel also agree that the process currently in place for reviewing British Standards (under the British Standards Institute) is the correct one. This process involves the relevant experts and evidence. Dame Judith Hackitt’s independent review of the Building Regulations and fire safety system is also examining the testing, labelling and marketing of fire safety products.’