Grenfell Tower, Toxic Smoke from PIR

Grenfell Tower_PIR foam_2
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Grenfell Tower_PIR foam_1

Grenfell Tower victims ‘poisoned by cyanide released by burning insulation boards used for cladding’. Three of those injured in the fire are known to have been treated with an antidote for hydrogen cyanide poisoning and fire toxicity experts say the thermal lining was an ‘accident waiting to happen’.

Experts said the thermal lining, fitted in the cladding process, is said to give off the deadly gas when alight. Prof Richard Hull said: “It has been an accident waiting to happen. Fire toxicity experts claim their positioning – between the new cladding facade and the existing ‘70s brickwork of the building – meant every flat could have been filled with enough gas to kill those inside. Three of those injured in the fire are known to have been treated with an antidote for hydrogen cyanide poisoning in hospital but it is thought the number of those affected may be higher. Pinning down what role it played in the deaths of the victims, now thought to be 79 or more, may never be known because of the victims’ condition.

Heat or Smoke? What kills people in a fire!

PIR Toxic Smoke, Cyanide
PIR Toxic Smoke, Cyanide
PIR Toxic Smoke, Cyanide

Speaking Richard Hull, professor of chemistry and fire science at the University of Central Lancashire, told Sky News: “The outside wall of the building had 150mm of PIR foam (fitted), and once the fire had spread to that every flat would have its own source of PIR foam, which would have produced enough hydrogen cyanide to kill all the people in that flat.” The insulation was made of Polyisocyanurate (PIR), rigid plastic foam sandwiched between two sheets of aluminium foil to create 15cm-thick boards.


Although PIR itself is flammable, the aluminium foil is supposed to disperse flames and prevent it catching fire. It was fitted behind the cladding and in front of the old brickwork as part of the refurbishment process. Professor Hull, who co-authored a peer-reviewed study in 2011 which established that PIR was the most toxic six insulation materials added: “It’s been an accident waiting to happen and unfortunately we’ve got to the stage now where the accident has happened and we’re standing here saying ‘I told you so’. “It would have been much better if people had listened to us earlier on when we published the report.”

How Polyphen® works

EPS and Phenolic foam combine the best qualities of each to produce the STRONG Polyphen® foam, EXCELLENT fire resistance, EFFICIENT thermal insulation. EPS is renowned for its strong mechanical properties and ability to be formed. Phenolic foam owns its exceptional fire resistant properties. In a fire situation, the EPS will decompose and evaporate. When this occurs, the Phenolic foam is left in a honeycomb shape and acts as a fire buffer.

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