Last edited 25 Jun 2017

Grenfell Tower fire

Grenfell-Tower-fire1.png

On 14 June 2017, a fire broke out in Grenfell Tower, a block of flats in North Kensington, London. The fire started shortly before 1 am and engulfed the building within 15 minutes. As of 19 June 2017, 79 people were confirmed to have died or were presumed dead.

While the cause of the fire is as yet unknown, the speed of the fire’s spread is believed to have been contributed to by the recently-installed exterior cladding, a kind that has been cited as contributing to similar fires in high-rise buildings around the world in recent years.

The 24-storey Brutalist concrete tower block was designed in 1967 and completed in 1974. It measures 67.3 m (220 ft) high and contained 120 flats. In 2015-16, an £8.7 million refurbishment was undertaken by Rydon Ltd, which included new windows and aluminium composite rainscreen cladding.

Rainscreen cladding systems are formed of relatively thin, pre-fabricated panels intended primarily to prevent significant amounts of water from penetrating into the main wall construction. The majority of the thermal insulation, airtightness and structural stability required by the building envelope is provided by the second, inner part of the wall construction - in this case the existing wall.

According to Rydon, the cladding system was intended to improve the building’s thermal performance and to give it a ‘fresher, modern’ look. Installation of the cladding was undertaken by Harley Facades, but at least 8 other contractors and subcontractors were involved in aspects of the refurbishment.

The Reynobond cladding used consisted of a polyethylene core sandwiched between, and fusion bonded to, two aluminium sheets. This is a commonly-used form of ACM cladding (Aluminium Composite Material), however, cladding panels with a mineral rather than 'plastic' core are considered to offer better fire performance.

Fire safety experts have speculated that the cladding could have created a chimney-effect in the void between the itself and the original concrete façade, which may have contributed to the speed at which the fire spread.

Several other major high-rise fires have been attributed to similar cladding systems in recent years, including; the Lakanal House fire in Camberwell (2009) [see image below], Wooshin Golden Suites fire in Busan (2010), Lacrosse Tower fire in Melbourne (2014), and The Marina Torch and The Address Downtown fires in Dubai (both 2015).

Lakanal House.jpg

Grenfell Tower is managed by a tenant management organisation – Kensington and Chelsea Tenant Management Organisation (KCTMO) – on behalf of Kensington and Chelsea Council. Criticism was levelled at KCTMO in the aftermath of the fire, and attention was drawn to the residents’ organisation, the Grenfell Action Group, which has repeatedly expressed fire safety concerns.

Controversy surfaced over the lack of common fire alarms, and confusion regarding the 'stay put' fire advice given to residents, which recommended that in the event of fire, they should wait in their flats for rescue, rather than attempting to escape. This is a common strategy in such buildings, as the subdivision of the overall building into fire compartments (in this case individual flats) should prevent fire from spreading. In this case however, the compartmentation may have been compromised by the newly-installed cladding, which allowed fire to spread up the outside of the building.

There was also concern about the absence of a sprinkler system. Part B of the building regulations requires the installation of sprinklers in new residential blocks of more than 30m in height, but it does not require that they are retrofitted in existing blocks.

After the Lakanal House fire in 2009, a report was published which recommended the installation of sprinklers in 4,000 tower blocks across the UK. However, the government declined to bring in prescriptive rules for developers requiring them to retrofit sprinklers, saying; "...we consider a regulatory requirement is unnecessary and disproportionate".

The British Automatic Fire Sprinkler Association said it would have cost just £138,000 to install sprinklers to Grenfell Tower, at an average cost of £1,150 per flat. However, such work is disruptive, and local council leader Nick Paget-Brown suggested there was not a collective view among residents in favour of sprinklers, telling BBC's Newsnight “We are now talking retrospectively after the most enormous tragedy, but many residents felt that we needed to get on with the installation of new hot water systems, new boilers and that trying to retrofit more would delay the building and that sprinklers aren’t the answer.”

The Regulatory Reform (Fire Safety) Order 2005, which came into force in 2006, requires that owners of premises other than private dwellings appoint a responsible person who takes reasonable steps to reduce the risk from fire and makes sure people can safely escape if there is a fire. Fire authorities no longer issue fire certificates, but are the main agency responsible for enforcement, carrying out inspections, assessing complaints and undertaking investigations. However, a review of the Order published by the Department for Business Innovation & Skills in 2013, found there was considerable discretion as to how each fire authority approached its duties, and that many small businesses were not aware of their responsibilities.

Successive housing ministers have been criticised for delaying a review of fire safety regulations and Approved Document B of the building regulations for four years, following the recommendations made after the Lakanal House fire.

On 16 June 2017, Prime Minister Theresa May announced a public inquiry would be held, while urgent safety reviews were conducted into thousands of similar tower blocks, particularly those renovated with the same cladding system.

It was also announced that The Metropolitan Police had launched a criminal investigation, working with the Health and Safety Executive and London Fire Brigade. Speaking on 19 June, 2017, Chancellor Philip Hammond said; "My understanding is that the cladding in question, the flammable cladding which is banned in Europe and the United States, is also banned here... There are two separate questions. One is: are our regulations correct? Do they permit the right kind of materials and ban the wrong kind of materials? The second question is: were they correctly complied with?"

On 18 June, the government required social housing owners to compile lists of buildings with aluminium composite cladding panels and buildings more than 18m high by the end of 20 June 2017. Owners must then send samples of any Aluminium Composite Material (ACM) cladding for fire tests. A letter from Melanie Dawes (File:Acm cladding checks.pdf), Permanent Secretary for the Department for Communities and Local Government (DCLG) to all local authority and housing association chief executives stated; “Once inspections are completed and necessary work identified, DCLG will work with housing associations and local authorities to identify the most appropriate options for supporting funding.”

On 21 June 2017, Melanie Dawes wrote a similar letter to owners, landlords and managers of private residential blocks offering testing of ACM cladding, paid for by DCLG. Ref https://www.gov.uk/government/publications/safety-checks-on-private-residential-blocks

On 22 June 2017, the Royal Institute for British Architects (RIBA) published a Statement on Design for Fire Safety, including guidance for members on fire safety following the fire at Grenfell Tower. Ref: https://www.architecture.com/knowledge-and-resources/knowledge-landing-page/riba-statement-on-design-for-fire-safety

On 23 June 2017, the Police confirmed the fire started in a Hotpoint fridge freezer. They also announced that small-scale fire tests had been carried out on the Reynobond ACM cladding and Celotex insulation and both had failed. Detective Superintendent Fiona McCormack said; "The insulation was more flammable than the cladding. Tests show the insulation samples combusted soon after the test started."

On 24 June 2017, the government issued a Statement from the Secretary of State regarding the cladding testing failure rate. Ref https://www.gov.uk/government/news/statement-from-the-secretary-of-state-regarding-the-cladding-testing-failure-rate

It confirmed that all the cladding samples so far, that is, samples from 34 high-rise buildings in 17 local authority areas, had failed a combustibility test carried out by the Building Research Establishment (BRE). Fire and rescue services are being asked to conduct fire safety inspections of those buildings to decide what remedial works might be required.

However the statement makes clear that:

...a failure in testing of the cladding does not necessarily mean that a building will have to be evacuated; the decision by Camden Council to evacuate 4 of the 5 towers on the Chalcots Estate was because the failed testing of the external cladding was compounded by multiple other fire safety failures which the fire inspection team found within the buildings.

See also: ACM cladding, and Celotex RS5000 PIR insulation.

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Comments

The planning application for this work did specify (and only specified) a fire-retardant insulation product, Celotex FR5000. It is not as thermally insulating as the polyethylene Celotex PE5000 - so this was a conscious decision at the outset by the design team to place fire performance above insulating performance.

This decision was evidently reversed subsequently, and this second decision process to place fire performance lower needs to be evidenced for examination and understanding.


Where in the planning application does it say that?


The product used was Celotex RS5000 PIR insulation, which is polyisocyanurate.


Just as a query with regards to the design concept and decision making with regards to the comment above referring to Celotex RS5000 PIR insulation.

Would i be correct in my assumption that this should have been covered in some aspects by a design risk assessment that should have been completed as part of the the contract and duty under the CDM 2015 Regulations?

If this is so given the terrible events of the Grenfell Tower fire, where does the main duty lie for the use of the correct items for fire as opposed to thermal aspects which may have been part of the hierarchy of control when completing a design risk assessment?