Research conducted following the Grenfell Tower fire in London shows the UK building materials testing regime may be fatally flawed.

The study – commissioned by the Association of British Insurers and conducted by the UK Fire Protection Association – has found some test fires under “real-world” conditions are 100 degrees hotter than those created in standard tests.

The research was submitted to an independent review of building regulations and fire safety.

The current testing regime sometimes examines cladding materials as a sealed unit, when in practice they often include gaps, are pierced by vents or ducts, and cover more extensive areas.

A test fire conducted by the Fire Protection Association using cladding filled with gaps, leaky sides and some ventilation found the cladding rapidly caught fire along a six-metre stretch.

A test fire conducted under standard conditions, with sealed cladding, climbed only 1.5 metres before self-extinguishing.

Fires under the official testing regime use only wood, whereas real-world fires can contain about 20% plastic. A test fire conducted with plastic produced flame lengths one metre longer than in a wood-only fire. The plastic fire was 100 degrees hotter than standard test fires and exceeded lab safety conditions.

Building materials such as aluminium lose much of their strength at higher temperatures, the study shows.

The researchers say fire safety measures often rely on assumptions about how long it will take a fire to penetrate certain areas of a building. Fittings such as vents make a big difference to this, and must be realistically modelled.

The Association of British Insurers has called for an end to the use of combustible materials in construction and a reformed testing regime replicating real-world conditions.