Grenfell fire inquiry told of safety flaws introduced over more than decade
Fire lifts and fire mains in the building were unsuitable, said an expert witness.
A litany of fire safety flaws introduced at Grenfell Tower over more than a decade have been set out at the inquiry into the disaster.
Dr Barbara Lane, an expert witness who analysed the fire for Sir Martin Moore-Bick’s investigation, said safety measures within the building were not suitable and many external materials flammable.
She is one of four specialists due to give evidence about the inferno this week, but did not provide an opinion about fire-performance, which she is expected to give at a later date.
Her forensic examination painted a picture of a refurbishment of the external wall and flat windows that was riddled with errors.
The refit was overseen by the Kensington and Chelsea Tenant Management Organisation and contractor Rydon between 2012 and 2016.
Combustible material was found around the window frames – including plastic uPVC lining, rubber EPDM sealant and insulation – while it had no cavity barrier to prevent the spread of flame.
This meant it appeared not to comply with Approved Document B of the building regulations, Dr Lane said.
The cladding system itself was Reynobond 55PE rainscreen panels with a 3mm polyethylene core that was combustible, she continued.
An inspection of the site revealed at points there were spaces of “15 to 30mm at the edge of the panels”, she told the hearing, adding: “In these gaps polyethylene is clearly visible and polyethylene is combustible.”
Cavity barriers intended to contain the spread of fire between floors were incorrectly installed – including a horizontal barrier installed vertically.
There appeared to be no cavity barriers installed at the top of the tower either, the inquiry was told
The building regulations say any material used on a structure more than 18 metres in height should be of “limited combustibility”, which Dr Lane defined as “either a non-combustible material or a material that produced very little flame”.
The 24-storey structure was originally built with walls that were “entirely non-combustible”, meaning a “single system with no void or a space within the exterior wall”.
Work done on the lifts in 2005 and 2012-16 left them unfit for evacuating the building of vulnerable residents and aiding the emergency response, Dr Lane said on Monday.
They lacked features including an escape hatch, a secondary power supply or doors that can resist a fire for 60 minutes, as outlined in Approved Document B of the building regulations, it was heard.
The block’s dry rise system – pipes through which the fire service pump their own water into the building – was also said to go against statutory guidance.
A gas pipe running from the basement throughout the building was installed in 2016 and remained exposed at key points during the fire, the expert continued.
The riser – one of six running vertically up the block – moved horizontally into the flats, where it penetrated both the protected stairwell and flat wall.
It had been installed after one pipe was found to have a gas leak and pierced a compartment wall in one flat on 13 floors of the tower.
Dr Lane said: “The pipe should be fire-stopped at each compartment wall it penetrates, or enclosed with a protected shaft.
“I understand that these works to the horizontal pipes were planned for June 2017, although I have seen no evidence that any of these works had commenced by June 14 2017.”
Dry rises rely on good water pressure to work against gravity, unlike wet mains, which summon water from a pressurised tank already within the building.
Dr Lane, a chartered fire safety engineer and director at specialist design group Arup, said: “Eventually a height is reached where the water pressure that can be delivered by a dry main cannot effectively operate a fire hose.
“For this reason, the statutory design guidance limits use of dry mains to buildings less than 50 metres in height.
“For a building that is 50 metres or more in height, there is a requirement to provide a wet fire main.”
Grenfell Tower was 67.3 metres in height, Dr Lane’s report said.
Putting the failures in context, the expert said an effective firefighting lift counts as an “active” safety measure, while a fire main is a “defence in place” measure.
Fire doors and fire-resistant walls – both replaced in some form at Grenfell Tower in 2011 and 2016 respectively – count as “passive” safety measures.
The “very basis” of a stay-put policy requiring residents to remain inside during a fire, like that in place at Grenfell Tower, was these three measures working successfully, she continued.
Dr Lane’s report, published a fortnight ago, said all of the flat entrance fire doors did not meet building regulation standards.
The statutory guidance makes no provision within the building for anything other than a stay-put strategy Dr Barbara Lane, expert witness
Residents in the west London block were told to remain in their flats for almost two hours after the fire broke out, a decision which it is feared led to the disaster being so costly.
“The statutory guidance makes no provision within the building for anything other than a stay-put strategy,” Dr Lane said.