In prime minister’s Question Time on 21 February, Theresa May responded to a question about why there are still people living in tower blocks with cladding that has been identified as unsafe.

Mrs May highlighted the fact that immediately following the appalling fire at Grenfell Tower, local authorities and others had worked with their local fire authorities to ensure that action was taken where it was thought necessary, to ensure the safety of the occupants.

These swift steps dealt with any immediate risk, whilst effective long-term solutions are sought. It is those long-term solutions that we now need to focus on.

The Ministry of Housing, Communities and Local Government (MHCLG) has stated that: 'The Government will consider providing financial flexibilities for local authorities to undertake essential fire safety work to make buildings safe.'

Regardless of whether insurance companies are prepared to pay out in the long term, local authorities should therefore be able to get some financial support to get the job done. In either case, it is crucial to gain a good understanding of the precise extent of the work (and therefore the amount of funding) that is required.

The DCLG testing programme, using the rigorous BS8414 test method, was an initial step to clarify which cladding solutions could be considered safe. Since those first tests in July and August 2017, additional full system BS8414 tests have been carried out — currently being signed-off by the BRE — which show several further solutions that can be deemed compliant with Part B of the Building Regulations.

As new information has been coming to light, the official guidance has been updated regularly, with the most recent data release from MHCLG on 22 January 2018. It should be noted that the broad guidance remains that any wall system containing a PE cored ACM cladding panel (such as was on Grenfell Tower), even when combined with non-combustible insulation, would not be considered compliant.

At the other end of the scale, systems with an A2 rated, solid-cored ACM, are deemed to have passed the test, regardless of whether they are combined with rock fibre, PIR or phenolic insulation, with the proviso that different products from different manufacturers will vary, which may affect fire performance.

It is those cladding systems with FR cored ACMs that present the greatest complexity. The Government tests on these systems yielded a pass result for rock fibre and a marginal fail for PIR and phenolic. The data release document states: 'However, it is important to note that there are many different variants of this cladding and insulation and it is possible that products from different manufacturers may behave differently in a fire.'

It should not be assumed therefore, that FR core ACMs in combination with rock fibre are automatically compliant. On the other hand, more recent tests have shown that two cladding systems using FR cored ACMs and one brand of phenolic insulation, are in fact compliant with relevant requirements of the Building Regulations. This means that some buildings, which are insulated with that brand of phenolic insulation, may not require remedial work or may require less than was originally estimated.

The BRE holds a register of all cladding configurations which have been successfully tested to BS8414 at: www.bre.co.uk/regulatory-testing.

Remember that BS 8414 results only apply to the specific design tested and seek professional advice and guidance as to whether your system complies. Note also that recent tests may not yet be listed on the BRE website. You can refer to the manufacturers and/or designer of your current system to get the latest information.

With the greater range of systems that have now passed the critical BS8414 test, there may well be a smaller number of buildings on which remedial work is required, and the remedial works that are required may be far less onerous than had hitherto been thought.

Adrian Pargeter is head of technical and marketing at Kingspan Insulation