EXOVA'S reports used by developers to show how combustible cladding systems meet safety standards do 'not seek to accelerate compliance with building regulations', insists the Warrington-based company.

The laboratory testing specialist, which has an Exova Warringtonfire site in Howley, on Holmesfield Road, is one of the UK's accredited bodies that produces 'desktop assessments' (DAs) for clients.

The assessments have been reported as being a factor in explaining how flammable material has become more common on tall buildings.

As reported by BBC Newsnight, combustible cladding has been permitted at some sites partly based on reports arguing fires involving combustible aluminium panels 'would behave similarly' to ones with non-combustible ceramic tiles.

The confidential reports contained assessments that showed how a given cladding design was safe and met legal standards.

The two reports obtained both related to a style of cladding system similar to that used at Grenfell Tower – a combustible insulation material underneath aluminium composite panels.

But neither of the reports proposed using the same materials as those used on Grenfell Tower.

Both reports related to aluminium cladding containing fire retardants.

The DAs have come in for criticism following the Grenfell Tower tragedy last month, in which at least 80 people died.

But an Exova spokeswoman issued a statement to the Warrington Guardian outlining the purpose of such an assessment.

She said: "Exova's specialist fire business provides a range of services that help to deliver fire safety across many sectors around the world, including the built environment.

"Exova is one of the accredited bodies in the UK that produces DAs for clients.

"The purpose of a DA is to provide a qualified assessment, based on a large body of testing evidence and detailed analysis, on whether a cladding system meets the requirements of building regulations."

However, DAs are not used alone, with several regulatory routes available, and used, to demonstrate to an inspector that cladding is safe on a tall building.

The spokeswoman added: "As an independent accredited body, our role in producing the DA is not to enforce building regulations, but to provide materials testing and assessment services against national or international standards, as required by our clients.

"This assessment is based on criteria set by various standards bodies.

"A DA does not seek to persuade, or accelerate compliance with building regulations – to suggest otherwise would be a fundamental misrepresentation of the established, prescriptive methodology of an assessment.

"After submission by the client to the building control body, the assessment is either agreed by building control or more information is required by the building control authority to demonstrate the cladding system meets the requirements of BR 135.

"It is also important to emphasise that a DA is not used in isolation, nor does it provide formal approval for the use of a certain system.

"Rather the client uses the report to demonstrate whether that system meets a specified standard, e.g. BR 135."

It has also been confirmed that cladding on UTC Warrington, on Dallam Lane, is not similar to the material used on Grenfell Tower.

A spokesman for the Education and Skills Funding Agency, which is responsible for the safety of the site, said: "UTC Warrington have been working with all parties to confirm the cladding criteria.

"From this review it is known that it is not an aluminium composite panel, which was similar to the Grenfell Tower.

"The ventilation strategy is based around each of the rooms within the building and throughout the floor levels being serviced by a comprehensive arrangement of mechanical air extract and supply systems.

"Due to the mechanical nature of the system, the building has no need for any opening windows.

"The system fully complies with the latest building regulation requirements."