Grenfell Tower Fire: How a Structurally Fire-Resistant Building Became a Death Trap

The fire that consumed Grenfell Tower on 14 June 2017 was a horrifying example of how a combination of regulatory failures, flawed decisions during refurbishment, and inappropriate materials can turn a seemingly safe building into a death trap. Despite its reinforced concrete structure, which is generally impervious to fire, the building became an uncontrollable inferno due to several contributing factors.

1. Inappropriate Use of Combustible Cladding

The primary contributor to the rapid spread of the fire was the use of aluminium composite material (ACM) panels with highly flammable polyethylene cores. These panels were installed during a 2012–2016 refurbishment aimed at improving the building's energy efficiency and aesthetics. When the fire reached the exterior of the building, the ACM panels acted as fuel, causing flames to spread vertically up the tower in a matter of minutes.

The choice of cladding was heavily criticized. The inquiry revealed that the polyethylene-filled ACM panels were chosen despite there being safer, albeit more expensive, alternatives. The cladding’s use in high-rise buildings was already controversial, given its known fire risks, which had been identified in fires in other parts of the world.

2. Fire Spread Through Insulation and Other External Components

In addition to the ACM cladding, the insulation material used in the refurbishment was also flammable. The inquiry found that Celotex RS5000, a polyisocyanurate insulation, was used on Grenfell Tower’s exterior despite its combustible properties. Once the fire penetrated the cladding system, it ignited this insulation, accelerating the spread of the fire.

This was exacerbated by poor installation and the absence of functional fire barriers between the floors, which allowed the fire to travel without being contained. The window frames and infill panels also lacked fire-resistant properties, contributing further to the rapid spread.

3. Gaps in Regulatory Systems and Testing

One of the major institutional failures identified was the inadequacy of the regulatory framework governing the use of building materials. At the time of the Grenfell refurbishment, the Building Regulations permitted the use of materials that passed limited, small-scale fire tests. However, these tests did not accurately simulate how materials would behave in a real fire scenario, especially when combined in cladding systems like that on Grenfell Tower.

Moreover, the materials used were certified based on outdated or incomplete fire testing data, providing a false sense of security. The inquiry report highlighted how fire safety regulations allowed dangerous materials to be approved due to weak enforcement and interpretation.

4. Mismanagement and Negligence During Refurbishment

The inquiry identified critical failures in communication and coordination between various stakeholders involved in the tower's refurbishment. Key decisions regarding the choice of materials were made by contractors and subcontractors without sufficient regard for safety. Design flaws in the way the cladding system was installed further reduced its fire resistance.

The contractors, architects, and consultants involved in the refurbishment failed to ensure that fire risks were fully considered, and there was little oversight by those responsible for managing the building, particularly the Kensington and Chelsea Tenant Management Organization (KCTMO).

5. The Failure of the “Stay Put” Policy

Grenfell Tower was designed to follow a "stay put" policy in the event of a fire, meaning residents were instructed to remain in their flats unless the fire was directly affecting them. This strategy relies on the principle that fires will be contained within individual flats and will not spread externally. However, once the fire reached the cladding, the building’s exterior was quickly engulfed in flames, rendering the stay put policy dangerous and ineffective.

The London Fire Brigade (LFB) was slow to abandon the stay put policy, leading to confusion and delayed evacuations, which contributed to the high death toll. The inquiry report severely criticized the LFB’s handling of the situation and lack of preparedness for a high-rise fire of this nature.

6. Historical Warnings and the Government’s Inaction

Warnings about the fire risks associated with combustible cladding had been circulating for years before the Grenfell disaster. Notably, the 2009 Lakanal House fire in South London, which also involved combustible cladding, should have spurred action. However, despite the lessons from that tragedy, the government did not tighten regulations or take meaningful action to address the risks posed by combustible materials in high-rise buildings.

Warnings from fire safety experts and industry bodies went unheeded, and no decisive measures were taken to mitigate the known risks before the Grenfell fire.

7. Institutional Failures

The Grenfell Tower Inquiry revealed widespread institutional failures that contributed to the disaster. The Kensington and Chelsea Borough Council and the Tenant Management Organization were found to have ignored complaints and concerns from residents about fire safety for years. Additionally, the building control process, which should have flagged potential fire risks, failed to identify or address the dangers posed by the ACM cladding and insulation.

Conclusion

The Grenfell Tower fire exposed profound failings in fire safety regulation, building materials testing, refurbishment practices, and emergency response. These issues, combined with the inappropriate use of combustible materials, turned a structurally fire-resistant building into a death trap. The lessons from this tragedy must serve as a wake-up call to ensure that fire safety is prioritized and that those responsible for building safety are held to the highest standards.

References

1. Grenfell Tower Inquiry: Phase 2 Report, Volume 1: "The Path to Disaster".

2. Grenfell Tower Inquiry: Phase 2 Report, Volume 4: "The Refurbishment of Grenfell Tower"​.

3. Grenfell Tower Inquiry: Executive Summary​.

4. UK Government Building Regulations and Fire Safety Updates (2020)​.