When arsonists attacked Scarborough’s iconic Pagoda building recently, they might have felt short-changed.

Instead of a spectacular blaze, the result was more of a damp squib, as fire-retardant (FR) treated timber limited the damage to less than 1% of construction costs.

The timber deck and main structure were treated with retardants from Arch Timber Protection. Without these, Scarborough Borough Council believes the entire building would have been gutted – at a cost of more than £200,000. The treated timber caused the fire to self-extinguish and the fire brigade weren’t needed.

It’s a graphic example of the effectiveness of FR timber. With modern construction calling for increased safety through fire protection of building components, particularly the use of timber and timber-related products in public buildings, it’s little surprise that the most recent figures show a fall in the number of fire-related deaths.

The Office of National Statistics reveals the number of fire deaths recorded in the UK fell to 484 (12 months to June 30, 2005) from 580 in the previous year. This is the lowest total since 1958.

In its guide to FR treatment of solid timber and panel products, the Wood Preserving Association (formerly the BWPDA) estimates the different costs of fire, including property damage, death, pain and suffering and precaution costs, at £4.7bn for the UK.

And, while the use of FR timber and timber products is helping to bring this figure down, the WPA points out that, just because wood is up-rated by flame retardant treatment, it’s not a substitute for good design and workmanship.

“The flame retardant pre-treatments recommended for the various commodities or end use situations are complementary to good design, workmanship and site practice – not a substitute for them,” states the guide.

Legislation minefield

It’s a good point. But the real challenge for merchants and importers is understanding the minefield of legislation concerning FR products – and making sure that the product they supply is both fit for purpose, and meets all legislative requirements.

“One part of the problem is that merchants tend to be ‘jacks of all trades’, and so, unless they have good systems in place, they purchase on price, ease of availability – or whether they like the rep,” said Keith Fryer, co-director of merchant and importer T Brewer and Co Ltd.

The first challenge is knowing what the different types of impregnation treatment are. There are currently three types: DI (dry interior); HR (humidity resistant); and LR (leach resistant).

Stephen Cope, marketing executive of Montague L Meyer, is on the WPA’s fire retardant committee. He believes that many companies are still in the dark about the differences between treatments and the requirements of the legislation, with many firms unwittingly selling products that are breaking the law.

“Some companies are selling FR products that are technically illegal without the faintest idea they are breaking the law,” he said. “As a result, some get an unfair advantage over companies doing it right.”

Despite the work of industry organisations such as the British Woodworking Federation and the WPA, confusion still exists, but, given the complex nature of the legislation, it is hardly surprising.

There are three main applications for FR treated timber and wood-based panels: building construction, transport, and applications like exhibition stands and furniture. Timber treated with Arch’s Dricon, for example, has recently been used in high-profile applications. These have included the Padstow Lifeboat Station, the National Assembly for Wales, and the Robin House Children’s Hospice in Balloch, Scotland.

FR standards

Currently, the UK operates two systems against which the usual levels of performance required of impregnation FR treated timber and wood-based panels are classified. The principal standard that has been used for many years for assessing the reaction to fire performance of wood building materials is the British Standard, BS 476.

The test method most widely used for assessing the effect of FR treatments is BS 476 Part 7, which is used to classify a material in terms of the ‘spread of flame’ across its surface under the test conditions. In general, untreated timber or panel products fall into Classes 3 or 4: treatment with FR chemicals, like Arch’s Dricon or FirePro, from Osmose, can upgrade such materials to Class 1. This level, the highest achievable with this test method, is the performance required for wall and ceiling linings. However, in certain high-risk areas, such as escape routes, Building Regulations require a Class 0 standard of performance. “This is basically a measure of reaction to fire,” said Stephen Cope, “in other words, how quickly will a product start to burn because someone has put a match to it.” Quality FR treatments can also achieve this level of protection.

“Dricon is based on a unique blended, chemically-tested formulation,” explained Arch product manager Richard Adams. “It is suitable for all internal situations – including saunas and swimming pools – as well as exterior applications that are weather protected with a suitable coating. And, it is the only FR treatment in the UK to be awarded a British Board of Agrément Certificate.” Arch’s portfolio also includes Non-Com Exterior, which can be used to protect external timbers such as cladding, leaving a natural finish.”

Like Arch’s treatments, Osmose’s FirePro meets the newer Euroclass classifications of B and C (under European Standard BS EN13986) that are currently only relevant to plywoods used within the construction industry. Compliance with the Euroclass standard is a legal requirement in Europe under the Construction Products Directive for all panel products used in construction and allows the company to CE mark their timber (CE marking is not obligatory, but compliance with the requirements to be able to CE mark is).

There is currently no Euroclass product standard for solid timber, although it will come into force from October next year.

“There is a misunderstanding that Class 0 has been replaced by Euroclass B and Class 1 by Euroclass C,” said Mr Cope. “It has been in the market place but not in performance, because the tests are completely different.”

Osmose FirePro is applied to timber products in an industrial controlled treatment process using vacuum pressure impregnation. The products must be air- or kiln-dried after treatment.

PTG’s new facility

PTG Treatments has recently opened an FR treatment facility at Ilford, treating timber and panel products with Osmose’s FirePro.

“European legislation is superseding the British Standards,” said managing director Neil Ryan. “We have gone down the Euroclass route, which is similar, but not identical to the British Standards because they involve different test methods.

“We are now offering Euroclass B or C, and if someone asks for a specification to a British Standard we will work with them and explain how the new European Standards work.”

Arch takes a similar approach. “The timber trade could do more to help themselves,” said Richard Adams. “Education is the best route and we regularly hold seminars to keep merchant customers up to date. Merchants get enquiries but often don’t know where to go and don’t take them further. Those that do, we can work with to reach a successful outcome.”

It might be a complicated issue but, as the specialists confirm, education is the key. The challenge for merchants and importers is to make sure they understand all the requirements – before they get their fingers burnt.