Deadline for treated wood quality accreditation on the horizon

From July 2022 every wood treatment operation managed by or supplying members of the Timber Trade Federation must be quality assured by an independent third-party. As the deadline approaches, UK based wood treaters are likely to turn to the Wood Protection Association’s ‘Benchmark’ quality scheme.

The WPA Benchmark quality scheme provides independent confirmation that wood products have been treated correctly in accordance with BS 8417, the British Standard for preservative impregnated wood, and the WPA Code of Practice for Industrial Wood Preservation 2021. Whilst BS 8417 specifies the minimum levels of preservative penetration and retention for every application where wood is used, it does not provide recommendations on how to achieve these critical levels of protection. In this respect it points to the WPA Code of Practice for the essential process guidance.

The WPA Benchmark quality scheme operates on the principle that wood treated in accordance with the WPA Code will achieve the minimum penetration and retention requirements for the end use and service life set in BS8417.

“Benchmark broke new ground when it was launched ten years ago but it is now tried and tested with a proven track record.” says Gordon Ewbank, WPA CEO, who believes that the decision taken in 2020 by TTF members to require thirdparty verification of treated wood will be a major driver to change the way such products are marketed in the UK, building supply chain and buyer confidence and growing demand.

How WPA Benchmark works

WPA Benchmark verifies the quality of an individual treated wood product such as a fence post, decking joist or building component. The scheme provides independent confirmation for both sellers and buyers that a wood product is compliant with the standards set in BS 8417.

Wood treaters looking to join WPA Benchmark must be able to demonstrate that a consistent relationship known as the ‘Safe Relationship’ exists between penetration and retention requirements and the more easily measurable aspects of the treatment process, such as preservative concentration and pressure cycle. They must then be able to show that they can control these various aspects in subsequent treatment activities. Verification that a treatment safe relationship is in place for every product requiring WPA Benchmark certification is assessed by an independent auditor. Depending on the data provided by the treater this is carried out either remotely or at the treatment site.

Once a treater achieves accreditation the continued certification of their products is subject to an annual surveillance audit. Depending on the compliance history of a treater this too can be a remote audit to reduce costs.

Contact More details of the scheme and costs can be found in WPA/TTF Guidance Note TW07 WPA Benchmark QAS Executive Summary, available to download free of charge from www.thewpa.org.uk. Further information contact: Gordon Ewbank 07887 632471. Those lines for which the production process has been subject to audit and for which the required penetration and retention of preservative has been assured by direct testing or by safe relationship testing. Approved Products will normally be defined by end use/Use Class, species and service life as a minimum. The scope of Products approved will be recorded on a company’s Benchmark accreditation certificate and should be clearly stated in/on company marketing materials, online or in paper form.

Those companies operating a treatment plant or plants that have been subject to audit and shown capable of producing Approved Products under the terms of the Benchmark scheme. Not all materials produced by an Approved Treater will necessarily be Approved Products, depending on the scope of products submitted for audit.

The WPA has expanded its team of independent auditors to help meet demand for treaters seeking accreditation to WPA Benchmark before the deadline of July next year. Gordon Ewbank emphasises that process of accreditation does not happen quickly and can take a number of weeks if the required data is not available or is incomplete.

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