Grenfell tower block fire: what we know so far

Materials World magazine
,
14 Jun 2017
Photo: Natalie Oxford/Wikimedia Commons

The full extent of the tragic fire at Grenfell Tower in West London remains at this stage unknown – there are plenty more questions than answers, as rescue and relief remains the priority.

Several reports are suggesting that the building’s polyester powder-coated aluminium composite material (ACM) cladding, added in a refurbishment that was completed last year, contributed to the rapid exterior spread of the fire.

The refurbishment, carried out by East Sussex-headquartered Rydon, was reportedly awarded a ‘Good’ Building Research Establishment Environmental Assessment Method (BREEAM) rating. We contacted the BRE, but they were unable to offer any comment at this stage.

Speaking to the BBC, Graham Fieldhouse, a fire safety expert and Member of the Institute of Fire Safety Managers, said ‘It is clear that the building had recently had an ACM cladding cassette put on to the external parts of the building, which it’s quite clear from the pictures has certainly been the cause of the fire spread going up the side of the building […] Prima facie, the cladding has been the cause of the fire spreading up the external parts of the building.’ The ventilation cavity required to enable the rainscreen cladding system to dry out could have acted as a ‘chimney’ for the fire, causing it to spread.

The exact specification and fire rating for the cladding has not yet been confirmed, but the material was subcontracted to East Sussex-based Harley Curtain Wall Ltd. The company has since gone into administration, but its directors now trade under the name Harley Facades Ltd. A case study page on Harley Facades’ website lists the scope of works as over-cladding with ACM cassette rainscreen, window replacement, curtain walling, louvres and feature metalwork. 

The Fire Protection Association released a statement from Technical Director Dr Jim Glockling that referred to findings of a 2014/15 study it conducted into External Thermal Insulated Cladding Systems (ETICs), which concluded that a ‘chimney effect’ may quickly develop in a fire where inbuilt features such as vents or pipes are present, which would cause the very rapid consumption of the insulation and expansion of the damage area. ‘If these inbuilt features are prevalent in the building, such as bathroom vents located one above another on multi-storey apartment blocks then there is scope for ground to roof fire spread by external means with ingress at each encountered aperture,’ the report stated.

ACM panels have previously been blamed in part for fires in Australia, France, UAE, USA and South Korea.

Glockling said that ‘Without knowledge of the specific materials used we cannot say at this early stage if any of the conclusions above are relevant to this tragic incident, but the increasing use of combustible materials in construction needs to be addressed if further events are to be avoided.

‘It is the Fire Protection Association’s view that Building Regulations and its Guidance in Approved Document B have not included an appropriate impact analysis of the safety and resilience consequences introduced by the adoption of materials and methods with poor fire performance capability. There is a need for the Building Regulations and its Guidance to consider both the external envelope of the building and its resilience to fire ingress.

‘Many insulating materials may be used in ETIC systems and their fire performance characteristics can range from being non-combustible, to very flammable – it is a matter of choice, and clearly some choices are better than others.’

In his BBC interview, Graham Fieldhouse also asked why escape routes became so quickly clogged with smoke and why fire doors had not prevented the internal spread. ‘The doors should have held back the fire from a fire happening within a flat, so people should have had at least half an hour to evacuate the building, and that doesn’t seem to have happened here,’ he said.

Grenfell Action Group, a community group founded in 2010, made numerous warnings to Kensington and Chelsea Tenant Management Organisation (KCTMO), which manages the building, regarding its fire safety standards, blogging on numerous specifically about poor safety standards at Grenfell Tower and elsewhere in the Royal Borough of Kensington and Chelsea.

One such blog post, from November 2016, stated, ‘Unfortunately, the Grenfell Action Group have reached the conclusion that only an incident that results in serious loss of life of KCTMO residents will allow the external scrutiny to occur that will shine a light on the practices that characterise the malign governance of this non-functioning organisation.’

A spokesperson for Rydon said ‘We are shocked to hear of the devastating fire at Grenfell Tower and our immediate thoughts are with those that have been affected by the incident, their families, relatives and friends. Rydon completed a refurbishment of the building in the summer of 2016 for KCTMO on behalf of the Council, which met all required building control, fire regulation and health & safety standards.’