Following last week’s devastating fire at Grenfell Tower in London, the spotlight has fallen on how the fire was able to spread across the outside of the building. However, questions will also be asked about how the fire was able to spread internally too.
Some parts of the mainstream media have picked up on an early planning document from 2012. The document shows that building services engineering firm Max Fordham said that one of the options for installing new pipework could entail the partial removal and then replacement of firestopping material between floors.
The firm added that there would need to be further investigations before any conclusion around the pipework options was reached. There is a four-year time lag between that document and the 2016 refurbishment of Grenfell Tower, therefore the document only gives an insight to early discussion of options, not what actually took place during the refurbishment.
The contractor that carried out the Grenfell refurbishment work has said the work met all required building regulations as well as fire regulation and health and safety standards, and was passed by local building control.
However, like the issue of the cladding, it has brought a little-known aspect of building engineering to public attention and raised a debate about how well the regulations and guidance covers the area.
Firestopping is a passive fire protection system designed to ensure any fire and smoke remains contained in the apartment where the fire started. Part of that is down to fire-resistant walls and floors, but for compartmentalisation to be effective, any small holes and joints must be filled: including spaces around pipes.
Firestops are usually made of intumescent materials, whereby heat causes the material to expand and fill any spaces which could help fires spread. But according to fire services firm Hilti product manager Stephen Parrish, ambiguity in current fire safety guidance means intumescent materials are not always used.
“In the Approved Document B it says that you can firestop plastic pipes using cement mix, but obviously cement mix isn’t an intumescent seal,” says Parrish.
Approved Document B is the guidance accompanying UK Building Regulations. The document states that all gaps must be firestopped, but the regulations – which have not been subject to a major update since 2006 – are not prescriptive on what materials should be used.
Another problem, cited by Parrish, with current guidance in Approved Document B is the ambiguity around proving products are fire-resistant. Under the guidance, products must pass fire safety tests conducted as set out in British Standard (BS) 476. However, Parrish argues methods for testing products under the BS 476 do not always provide the most realistic conditions.
He would like to see a shift towards using European Standards, which he believes are more rigorous and make it harder for products to achieve a fire safety rating.
“In general, it would be fair to say that European Standards [EN 1366] are more specific and have separate test parts rather than [the] BS 476 broad brush method of test,” says Parrish.
Parrish says there is also ambiguity about accountability in the Approved Document B, something he believes needs to be urgently updated.
The tragedy could prompt an overhaul of fire safety guidance.
Max Fordham did not respond to New Civil Engineer’s requests for comment.