A fatal fire in a Scottish tower block last year triggered a review of cladding systems. As a result, the Building Regulations may be amended. What will it mean for manufacturers, installers and specifiers?
At midday on 11 June 1999, a fire started in a flat on the fifth floor of Garnock Court, a 14-storey residential tower in Irvine, Ayrshire. Within minutes, it burst through the window of the flat. Seconds later, onlookers reported that a vertical ribbon of cladding on one corner of the block was ablaze.

Ten minutes after that, the flames had reached the 12th floor. As the fire took hold on the outside of the building, it began to break into the flats above. By the time the fire brigade arrived, the nine upper floors of the building were engulfed in flames. A wheelchair-bound pensioner died in the blaze.

The cladding on the outside of the building was suspected of contributing to the fire's severity, and concerns were raised that housing blocks around the country could be at risk. This triggered a parliamentary inquiry into the extent of the problem, which was carried out by the Environment, Transport and Regional Affairs Select Committee.

The committee's findings were contained in a report published last month, Potential Risk of Fire Spread in Buildings via External Cladding Systems. The report's recommendations, if implemented, could have a wide-ranging effect on manufacturers, specifiers and installers of cladding. More specifically, cladding may have to meet new requirements, to be contained in Approved Document B of the Building Regulations.

The report does not go as far as recommending that any particular system on the market should be avoided, but it does insist that manufacturers test cladding in a more rigorous way than they do now. A new test is proposed that will recreate as closely as possible what happens when cladding is exposed to fire.

In the current test, a small section of a single piece of cladding, sometimes less than the size this page, is tested to ensure that it does not encourage the spread of flames across its surface. The committee concluded that this test does not reproduce a real fire scenario. Another point about the test as it stands is that it does not look at the complete system as it would be when installed in a building.

The committee has proposed instead that a test developed by the BRE be specified in the Building Regulations. In this, whole sections of cladding, including fixings and seals, are tested.

Triggered by what happened at Irvine, the report has also clarified whether cladding that forms a window unit (type 2 in the accompanying diagrams of the three main cladding systems) should be classed as cladding or a window. This was a major debating point for the inquiry, and its eventual decision to count these "preformed infill systems" as cladding has implications for their manufacturers and installers.

At Garnock Court, the "ribbon of cladding" that transmitted the fire was a strip of floor-to-ceiling PVCu window unit, which was divided into a glazed upper half and a grp lower half.

If the committee's recommendations are implemented, a similar system installed in a new block would have to be pretested to see how it behaved in a fire.

The committee's report addressed the technical debate over whether or not some glazing/ cladding systems should be subjected to the more stringent tests by re-emphasising a catch-all requirement already in the rules. This would "make it clear that any addition to the outside of a building which has the potential to lessen its resistance to external fire spread is subject to the Building Regulations".

A second implication of a reclassification of glazing panels is that their installers would be made more aware of the implication of their work on fire risk.

As Simon Taylor, a director of cladding installer Northern Heights, says: "Few others in adjacent disciplines understand the special problems associated with cladding to existing buildings.

"A window man may be blissfully unaware of the consequences of his work or the history of such work on high-rise blocks. If no allowance for fire design is made then the results are entirely predictable and well-known to the industry."

While Whitehall looks at whether the Building Regulations should be improved, local authorities are going to do the same with their tower blocks. The initial reaction – that 500 of them were going to have to be completely reclad – has calmed somewhat. In fact, nobody is really sure what the extent of the problem is, although it is a safe bet that councils will seek to modify rather than replace systems – if the regulations will let them.

Stephen Ledbetter, director of the Centre for Window and Cladding Technology, believes the most sensible way to proceed it would be "to carry out a risk analysis". This would still require a survey to gauge the extent of the problem, but would allow an informed decision to be made once the scale of the problem had been established.