The polyethylene filling in cladding panels used at Greenfell Tower and at least 82 other tower blocks has been given the lowest fire rating during testing.

As the United Kingdom Government announced an inquiry into building regulations and fire safety, results from the first of six tests aimed at testing different cladding systems found that the 3mm polyethylene filling in the panels used at Greenfell Tower achieved a category three rating, meaning that it has no retardant properties.

The test is the first of six which the government has order to be conducted which aims to allow experts to better understand how different types of cladding panels behave with different types of insulation in the event of a fire.

It involved subjecting a nine-metre high demonstration wall to a replica of a severe fire inside a flat as it spreads out through a window in order to see whether or not the material met the requirement to resist vertical fire spread.

It found that:

  • Burning droplets from the system were observed after five minutes
  • 30 seconds later, the rate of flaming droplets was sufficient to fuel growth of a fire at the base of the cladding.
  • Sporadic flaming at the top of the rig could be observed after seven minutes and fifteen seconds.
  • This became frequent within another 40 seconds, by which time the fire at the base was one metre wide and had flames which were 30 centimetres high.
  • By eight minutes and thirty seconds, the flame at the top of the rig was near continuous.
  • The test was terminated after eight minutes and forty-five seconds, at which time flaming could be observed several metres beyond the rig.

“The expert panel advise that the results show this combination does not meet current building regulation guidance,” a statement on the Department’s web site read.According to the department, 82 buildings throughout the United Kingdom are currently known to have this combination of materials within their wall cladding systems.In response, the government said it had appointed Dame Judith Hackitt, Chair of EEF, the Manufacturers’ Organisation, to lead an inquiry which will look at current building regulations with a focus on high-rise residential buildings.Set to report jointly to the Communities Secretary Sajid Javid and the Home Secretary Amber Rudd, the enquiry will examine:

  • the regulatory system around the design, construction and on-going management of buildings in relation to fire safety
  • related compliance and enforcement issues
  • international regulation and experience in this area.

Javid said the review was necessary to protect public safety.

“It’s clear we need to urgently look at building regulations and fire safety,” she said.

“This independent review will ensure we can swiftly make any necessary improvements.

“Government is determined to make sure that we learn the lessons from the Grenfell Tower fire, and to ensure nothing like it can happen again.”

The test was conducted by fire testing group BER Group.