The rapid rate of change in the timber preservative and treatment sector – the introduction of new products and developments in standards and specifications – inevitably creates doubts and uncertainty in the marketplace. These include a suspicion that ‘chemicals’ undermine timber’s green credentials; a feeling that quality of treatment and service life is not all it should be and confusion about preservative types. However, the British Woodworking and Damp-proofing Association is addressing these issues.

Managing suspicion

Suspicions about the use of ‘chemicals’ must be managed so that timber use is maximised for the sake of the environment. Life cycle analysis shows that treated timber retains its green credentials in comparison with alternative materials. Wood preservatives have been subjected to rigorous controls in the UK since the early 1970s, first under voluntary schemes and, since 1986, under the Control of Pesticides Regulations. Products are assessed for safety by independent experts before approval is granted and tough conditions are placed on their sale and use.

There are many chemicals in common use today which have never been assessed in this way, which are classified as more harmful if misused than the vast majority of preservatives, and yet are accepted as a fact of modern life. Nearly all such products will become subject to the controls applied to wood preservatives over the next 10 years as the UK implements the Biocidal Products Directive. Under tough new rules, this will involve first an assessment of active ingredients by the EC. Only when these are approved will wood preservatives themselves be considered for approval at national level throughout the EU. However, further action is needed at the point of use to ensure the safety achieved under the procedures are not undermined by careless use involving risk to health, safety and the environment.

The new BWPDA Approved Treater Scheme is designed to address safe and effective use of preservatives. The BWPDA has appointed a new staff member to support the scheme which is based around ISO 9000 certification, including appropriate quality standards; plant operators who have achieved the new National Vocational Qualification; and plant operation in accordance with the BWPDA Code of Practice for Timber Treatment Plants.

Revised Code of Practice

The third edition of this BWPDA Code of Practice was published in 1997. It was prepared by a group representing BWPDA, the Environment Agency and its sister organisations in Scotland and Northern Ireland and the Health and Safety Executive. The Code was funded through the Environment Agency and distributed to the industry by the BWPDA and its pre-treatment manufacturer members. There have been significant developments in environmental protection and health and safety legislation since 1997 and the Environment Agency has agreed to fund a further revision of the Code. A task group will meet under the auspices of BWPDA with representatives from the regulatory agencies, and a new edition is expected to be published next year.

The green perspective

It is necessary that treatment is carried out in accordance with appropriate specifications to ensure that where chemicals are used they are managed so as to deliver the durability required. It is much worse from a green perspective for chemicals to be used in a way that fails to achieve the desired effect since the environmental burden is increased to no purpose. BWPDA Approved Treaters will demonstrate their ability to produce safe and effective treated timber for use in situations where its lack of natural durability would otherwise preclude it from use. The scheme also incorporates a requirement for marking and traceability which will facilitate the implementation of disposal strategies when timber service life ends. The BWPDA will ensure that specifiers and users of treated timber are made aware of the advantages of obtaining supplies from Approved Treaters.

Changes to treatment specifications arising from European standards have the potential to confuse and alienate specifiers from using timber. These changes are also the subject of BWPDA initiatives to guide and advise. The BWPDA manual has long been a source of independent advice on preservatives, methods of treatment and use of treated timber. It is now the key source of information on the new specifications and is the only route to linking new-style specifications to service life. The manual gives specifiers the choice of simple specification phrases encompassing the full authority of the manual and the detail for those who want to understand all the options.

Confidence in place

The final part of the jigsaw to lift confidence in new preservatives is also in place. New European standards give manufacturers and suppliers the freedom to place wood preservatives on the market based on self-declaration that they meet the new performance requirements and are fit for purpose. While specifiers and users are protected by legal obligations on suppliers, suppliers themselves will look to their liabilities when making claims for their products. The new BWPDA Approved Preservative Scheme now offers suppliers and users the assurance that claims have been independently audited.

Approved products not only meet performance expectations but the approval links treatment to service life and ensures that all aspects of application and use are supported from delivery through stability in use, quality control and information on such issues as strength of treated timber and compatibility with fixings, fittings, adhesives and coatings.

These issues become more important as new preservatives are introduced and the choice becomes wider than the familiar creosote, CCA and solvent-based preservatives which have been the mainstay of the industry for over 60 years.