The large attendance at the Timber Trade Federation’s (TTF) recent Fire Seminar in London is testimony to the current high interest levels in fire protection following the Grenfell fire.

More than 100 people drawn from across the timber and timber preservative sectors were at the event, which detailed fire retardant specification and products.

Gordon Ewbank, chief executive officer of the Wood Protection Association (WPA), declared that fire protection /fire retardant specification was currently the “number one topic” for discussion.

“Without exception everybody you talk to in this industry who is involved in the fire protection of timber products has seen a large increase in enquiries,” said Mr Ewbank.

Mr Ewbank told delegates that the Hackitt Review looking into the Grenfell fire identified that the current system of building regulations and fire safety was “not fit for purpose and that a culture change was required to support the delivery of buildings that were safe, both now and in the future”.

He said the Hackitt report had identified shortcomings in product testing, labelling and marketing of products with regards to building regulations and fire safety.

He said the government was talking about banning combustible cladding materials on high-rise buildings. “This obviously has a knock-on effect for the timber industry,” he said.

Mr Ewbank explained the difference between reaction to fire classification and fire resistance, saying there was “enormous” confusion between the two.

“Fire treatments slow down the growth phase, giving more time to escape and save the structure and small fires will be extinguished more quickly.”

But he said it was not technically possible to improve the fire classification of wood to the top Class A specification.

He said the Wood Protection Association’s Approval Scheme for Flame Retardant products provided independent verification of flame retardant formulations applied to wood based materials, allowing full traceability of products through the supply chain.

The WPA is partnering with Local Authority Building Control (LABC) to design a national educational programme on enhancing the performance of timber in fire. It has put together a detailed project communications plan and sponsor group to push the initiative forward, with TTF and Wood Campus as co-sponsors.

David Hopkins, managing director of the TTF said that most of the issues to do with fire retardancy centred on panel products, so presentations at the seminar were heavily weighted towards panels.

Post-Production FR Treatment

Stephen Cope, of Meyer Timber, joined with Lonza’s Julie Hargreaves to cover post-production fire retardant treatment of plywood, detailing quality assurance,

Declaration of Performance (DoP), CE marking and the legal process of placing on the market.

“A treatment certificate is just a claim and is not evidence that the treatment works,” he said.

Nor does it give the field of application or that it has been placed on the market legally, while a DoP is a legal requirement and CE marking needed.

Mr Cope helped demystify clauses in wood panels standard EN13986: 2004, the Construction Products Regulation (CPR) and the Classification Report as evidence of type testing, as well as audited Factory Production Control certificates. Table ZA.2 calls up systems of Assessment from the CPR and shows the Reaction to Fire Classifications covered by System of Assessment 1, identifying the specific situation for which System of Assessment 1 (DoP) is required – including an improvement of the reaction to fire classification.

Meyer’s FR plywood product is fire tested by Warrington and has intended end uses/ field of application, as well as DoPs and CE marking.

“This is all about quality assurance and letting our customers know that the product does exactly what it says on the tin,” said Mr Cope.

Lee Christie of Koppers and Steve Adams of PTG, shared a case study of wood products with FR added post-production for delivery to a single site.

Looking at a 20mm larch cladding product enquiry, Mr Christie said it would check its database for the species and thickness requested, showing it had classification of B S1 d0 (Exova Warrington Fire).

Koppers’ Exterior Fire-X treatment process is controlled by the WorkNet control software to make sure every piece of timber is monitored and treated correctly. After packaging the FR treated product, documentation is produced giving the product specifications and classifications for the customer.

PTG has rebadged its treatment Sentrin FRX – the same as the Koppers Fire X treatment – to avoid confusion in the market.

Classifications for different species and thicknesses using the treatment are held. Mr Adams said its Sentrin Chromacoat system is a compatible coating system for use with Sentrin FRX.

Koppers and PTG highlighted that the FR chemicals used were WPA approved chemicals.

FR Treated OSB

David Murray, head of innovation at MEDITE SMARTPLY, detailed the company’s FR OSB for structural use in construction – the fire retardant is added during manufacture and applied to every strand, giving fire retardancy throughout the panel.

The product has both a DoP and CE marking.

The supplier of the fire retardant is Zero Ignition. A chemical reaction takes place between the FR and OSB, creating charring to protect the integrity of the board.

“The more FR products you put into a building [the more] you can reduce the fire risk,” said Mr Murray.

This helps with the STA Separating Distance Guidance aimed at new urban housing developments.

He pointed out that arson was the most common cause of a site fire and demonstrated a video of a room corner fire test of the FR OSB product at a BRE rig, showing the fire went out in a 40min duration test.

Mr Murray said structural panel products that are FR treated after production needed a new DoP.

“A new DoP needs to be issued after treatment to determine reaction to improved fire characteristics and any change in non-fire properties (structural) that may occur during treatment.”

And he reminded delegates that the DoP was a legal responsibility under the CPR when CE marking was applied.

Mr Murray advised suppliers to read the CPR, understand their responsibilities, upskill the workforce, inform their supply chain, check the DoP and ask for full evidence of certification.

“Never accept a pressure impregnated wood panel without a valid DoP declaring structural properties after treatment,” he said.

The Legal Question

Iain Garfield, partner and head of BPE Solicitors’ commercial team, advised and warned delegates of the potential legal pitfalls of supplying FR products.

“If a customer says to you he wants a specification for a project and you know it is not going to work, you can’t supply it without being responsible when it goes wrong,” he said.

Mr Garfield said to avoid liability with the customer, end-user and regulators it was important to have proper contract terms, provide products of satisfactory quality that were fit for purpose and be careful in product descriptions.

With FR products, he said suppliers could sub contract liability to the treatment company. Exclusion and indemnity clauses and insurance were important considerations, he added.

“Be careful when you make statements in publicity material if you can’t back it up.” During a question time, TRADA marketing and membership manager Rupert Scott said the industry needed to “shape up” and someone in the supply chain had to rise up to take responsibility should problems occur with products.

David Hopkins admitted there was some ambiguity in the regulations about responsibilities but said the first line of responsibility was the timber supplier who supplied the product.