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the right questions” of the companies treating their timber and “understanding if they’ve got the right answers”. This will help establish if the company is treating to the correct – and current – standard and that it can provide the correct documentation and certification. “From many conversations with
prospective customers, we have sometimes come up against companies in the market place that are using out of date certification to warrant their processes,” said Mr Gadsby. An additional problem, added Mr
Torkington, is easy accessibility to surface applications via online platforms such as Amazon. “People can buy a tub and spray or paint it on the timber and think it’s going to prevent fires – but they have no idea if it will because it hasn’t been tested and there is no
control over the application,” he said. Obviously the company would like to level the playing field for commercial reasons but it does have a strong sense of moral obligation to raise awareness of the issues “as ultimately the whole wood industry will suffer if there is a timber fire-related accident where inadequate treatment has been performed”. WJ’s Burnblock process is audited annually by Finotrol, a Finnish company that specialises in construction product certification and it’s a protocol that it hopes other treatment providers can be persuaded to adopt. And in the absence of any “policing” of the sector, WJ would like to see robust self-regulation. “The role of the Wood Protection
Association and the Timber Trade Federation should really be advisory,
whereby they provide the appropriate information and guidance for their members to follow best practice,” said Mr Gadsby. “We would like to see the treaters working together to self-regulate, such that appropriate regulations are followed,” he continued. “There is more than enough FR timber treatment to go around, especially in the wake of Grenfell. However, this situation could change dramatically if FR timber gets a bad reputation as an unviable material.”
“Our CE mark and Declaration of
Performance is backed by a chain of testing and auditing to prove the fire- retardant timber is fit for purpose. We firmly believe the UK should interpret the CPR as the EU does and fully control a life- protecting treatment process.” ■
FR treatment) must have a clearly defined manufacturing process. This process must be audited by a notified body which will verify the treatment process and/or CE mark the product. They will also be responsible for ongoing surveillance to ensure the accreditation is maintained.
The FR chemical manufacturer will have a fire classification report, by species, which is issued and audited by a notified body under Assessment and Verification of Constancy of Performance (AVCP) system 1. The company placing the fire retardant timber on the market or the treater would then be audited by a notified body under AVCP system 1 against the FR classification report. The notified body would grant the seller / FR treater with CE certification for their process. This is a Certificate of Constancy of Performance (CoCoP). A Declaration of Performance (DoP) can then be issued with each supplied batch of treated timber. The DoP ensures full traceability of the FR treated timber entering the supply chain. DoPs are species specific. Different species have different cell structures and/or densities, which can have a significant effect on the quantity of chemical required during pressure impregnation. As a result, the FR treatment process varies depending on the species in terms of treatment time and pressure. It is therefore essential that the species details are provided by the treater’s customer and the treater has the appropriate DoP to allow them to treat the specific species in question. FR treatment is also species specific. Generic terms such as Far Eastern plywood, softwood and hardwood are ambiguous and do not meet the requirements of an FR Classification Report and are therefore not CE compliant.
UNDERSTANDING COP AND DOP DOCUMENTS
Typical CoPs and DoPs will contain the following information:
• Product: details of the timber species, eg larch; what it is, eg solid wood panel,
tongue and groove profiled; and what fire retardant treatment has been used, eg Burnblock. Classification is valid for the end use as cladding or as support for cladding elements.
• Thickness: what is the nominal thickness of the material, ie 21.5mm.
• Density: what is the timber’s nominal density range, ie 650 - 750kg/m3
.
• Intake: how much dry FR material must be absorbed in line with the approved
factory control process. Dry amount of FR 36.5 kg/m3
.
• Substrate: details of the substrate that must be used to mount the timber onto any
substrates in classes A1 and A2-s1, d0 of at least 9mm thickness and with a density equal to or greater than 653kg/m3
.
• Fixation: how cladding should be fastened, eg mechanically fixed to the substrate.
• Air gap: details of whether an air gap (typically 40mm) behind the panel is
required.
• Mounting: how panels can be mounted, eg horizontally, vertically or both.
• Joints: how panels can be joined, eg vertical, horizontal joints or both.
• Reaction: reaction to fire classification: what rating has been provided for the
above conditions, eg B-s1,d0. Where first letter (B) refers to its fire rating. Where “s” refers to its smoke rating, with 1 being the least smoke produced. Although s1 is highest achievable on timber (some uses will only allow minimum smoke
FURTHER INFORMATION
TRADA wood Information sheet (WIS 4-11) – Wood-based panel products and timber in fire
TRADA wood Information sheet (WIS 2/3-3) – Flame- retardant treatments for timber products
14915: 2013 + A1:2017: Solid wood paneling and cladding - Characteristics, evaluation of conformity and marking.
EN 13986:2004+A1:2015: Wood based panels for use in construction – Characteristics, evaluation of conformity and marking
production, eg London Underground due to safety considerations). Where “d” refers to the amount of flaming droplets produced when subjected to a flame, with 0 being the lowest number produced, ie no droplets produced
AVCP EXPLAINED AVCP is a harmonised system defining how to assess products and control the constancy of the assessment results. This system safeguards the reliability and accuracy of the Declaration of Performance.
• Assessment of performance is a one-time activity
• The Verification of Constancy of Performance is an on-going process
• System 1, eg Fire retardancy – Product certification comprising the issuing
of a Constancy of Performance with determination of the product type and continuous surveillance by a notified product certification body. ■
www.ttjonline.com | May/June 2021 | TTJ
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