Proposed EU legislation aimed at severely restricting the use of CCA-processed timber from 2004 has been a major factor in the decision by timber giant Forest Garden plc to switch production at its site in Lockerbie from traditional chromated copper arsenate (CCA) to the copper-based wood pressure treatment Osmose Naturewood AC500.
The group claims that the move sets “an important industry precedent” and that other of its plants will shortly follow suit. Technically, the transition to Osmose Naturewood will not require any autoclave or processing changes at Forest Garden, although the new solution “allows for a faster production cycle, rather than needing 48 hours’ drying time”.
The new autoclave pressure treatment plant and dip tank commissioned in November last year has already produced marked benefits for the Lockerbie operation, according to site manager Peter Ross. Its large pumps, designed to “move fluid and air around the system at optimum speed”, have enabled the company to start pressure in the tank in around three minutes compared with more than 20 minutes with the previous system. Furthermore, the new plant offers improved control over the usage – and potential wastage – of valuable preservative, and enables Forest Garden to “change from one hazard class to another at just the click of a button”, according to Mr Ross. Osmose Naturewood covers hazard classes 1-4, although not hazard class 5 which applies to marine structural timbers.
The plant at Lockerbie, designed by Osmose in partnership with IWT of Denmark, is based around a 20x2m tank into which timber on tracks can be fed by remote control. Once the timber is in the tank, hydraulic pumps angle it 15O downwards so that excess preservative drips off the timber and is recovered by vacuum/scavenger pump for reuse.
The tank also has two ‘doors’ to minimise the time between removing one load and introducing the next. Timber emerging from the tank after treatment is “virtually drip free”.
The new treatment plant has a capacity to process 50,000m3 of timber per year. As a result, Forest Garden anticipates that around 20% of this capacity will be available to offer to other sawmillers and timber users. Indeed, Mr Ross confirmed that Forest Garden was “already deep in negotiation with other companies” interested in using the new facilities.
To assist clients with traceability and record-keeping, Osmose’s associated Worknet software package will provide them with a print-out of what has been processed and to which particular hazard class. Diagnosis of repair and maintenance issues can be effected via modem from the Osmose base in Marlow.
Restrictions by EU
Forest Garden explained that, while CCA-preserved wood has been used safely in garden structures for almost 70 years, the EU is expected to restrict its use in residential applications in order to “allay any potential public concerns about the arsenic content”. While continuing to back CCA-treated products, Forest Garden said: “We felt it was important to take a lead in ensuring our customers are able to benefit from an effective alternative well in advance of any legislative changes.”
Andy Hodge, European marketing manager for Osmose Naturewood producer Osmose Wood Preserving, underlined that the product has enjoyed “a decade of successful commercial use throughout Europe, North America, Australia and Japan”. The water-based preservative contains copper and an organic co-biocide – an alkaline copper quaternary (or quat) system – said to suit all structural timber, garden furniture decking, fencing, pergolas, playground equipment and landscaping accessories. It offers effective protection against brown and white rot, soft rot, and insects and termites, and is claimed to compare “very favourably” in cost terms to the CCA alternative in hazard class 3.
US moves
Mr Hodge explained: “The US’ top four DIY multiples Home Depot, Lowes, Menards and McCoys are already planning to move away from CCA-treated timber to ‘quat’ alternatives. By the end of 2003, it is estimated that copper ‘quat’ preservatives such as Osmose Naturewood will account for more than 75% of the alternative preservative market in the US and 90% in Canada – and we expect the UK to follow suit very soon.” Mr Hodge predicted that the early months of 2003 would see a significant proportion of users “making the transition to copper-based alternatives”, and that some of the bigger timber companies would opt for larger treatment facilities as a means of achieving “economies of scale”. Mr Hodge added: “You need to have efficient machinery to make money out of the material you are sawmilling. In the past, the industry has perhaps failed to realise fully that treatment is a way of adding value.”
Osmose Naturewood is one of three brands offered by Osmose (UK), the other two being Protim Clearchoice and Osmose Lifewood. Naturewood applies to timber that has been pressure treated with Osmose preservatives such as the Celcure AC range for external applications with both in-ground and out-of-ground contact, including timber decking, fencing, landscaping timbers and other outdoor timber projects.
According to Forest Garden, early customer response to Naturewood in the UK has been very positive – especially among multiples and other leading firms which are aware of the proposals to change EU legislation. “They have been pleased to see that we are making the change with our preservatives, knowing that the new legislation is coming through,” said group marketing manager Vicky Barker.
