Updated Briefing on Fire Safety Issues Arising from the Grenfell Tower Fire

Since the fire at Grenfell Tower in June 2017 we have been busy issuing briefings and advice to our clients. The Government have now published the results of the first fire test on an external cladding system similar to the one used on Grenfell Tower. This article will be useful to you if you operate, or employ staff in, any type of building, or you act as landlord for residential flats and premises. It is intended to provide an update and advice following the publication of the most recent fire tests.

Background to the Test

The first of a series of tests has been conducted on a full scale sample of the type of cladding system used in Grenfell Tower, 9 metres in height. The cladding system was of aluminium composite material (ACM) with an unmodified polyethylene filler, with foam insulation behind the panels and installed with fire breaks. This is known as a “Category 3 system” based on fire testing and heat output. The definitions of the three categories are shown below:

  • Category 1 Means that the result is in line with the requirements for a material of limited combustibility (Calorific potential ≤3 MJ/kg)
  • Category 2 means that the result does not achieve the requirements of category 1 but that it does have some limited flame retardant properties (Calorific potential > 3MJ/kg and ≤35MJ/kg)
  • Category 3 means that the result does not achieve the requirements of Category 1 or 2 and that it has no flame retardant properties (Calorific potential >35MJ/kg)

The purpose of the tests is to give a realistic simulation of a fire in a flat, or internal part of the building, exposing the external cladding system when installed in the way intended. It is important to note that this type of test involves the cladding system, not individual types of material within it. The test therefore takes account of the performance of the cladding system (including installed fire breaks and separation).

The tests are of course undertaken on the basis that the cladding system has been installed exactly as designed and intended and, therefore, represents the best case scenario in terms of performance. It is often the case that such systems on real buildings are not installed as intended due to defects in installation practice and this will normally result in a lower level of safety under fire conditions.

Results of the Test

The test showed a failure of the system to prevent the spread of fire. Burning droplets were apparent within 5 minutes and, within 8 minutes, the entire height of the 9 metre high test specimen was burning with the lower panels detaching and spilling more burning droplets causing a pool fire below. The installation would therefore not comply with the Building Regulations and, as demonstrated so graphically in the actual fire at Grenfell Tower on 14 June, would allow rapid vertical fire spread. The minimum test duration in the standard for cladding systems to be compliant is 40 minutes and even then only limited combustion and spread of flame has to take place.

Government experts have indicated that they do not consider any combination of aluminium composite panels with an unmodified polyethylene filler and foam insulation will meet the Building Regulations requirements. The full test report is available publicly and can be seen here.

Quadriga Advice

There will be a requirement to remove certain combustible cladding systems on high rise buildings. Therefore any proposed design and current installation of such systems that are now likely to be determined to be not compliant with the Building Regulations on high rise buildings, should be urgently reviewed with a view to using non-combustible materials. As is already starting to be the case, there will be the need for costly retrospective action where cladding systems are demonstrated not to meet the required standards.

Clearly, there will be further Government guidance issued after the remainder of the tests have been undertaken. We will keep you informed if there are further developments in relation to any changes to legal requirements or enforcement practice.

If you need any specific advice relating to fire safety, please contact Quadriga by calling us on 0118 929 9920 or click here to contact us.

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