From a sustainability point of view the timber industry has the "best material available" and treating timber prolongs the life cycle further, Alexander Prager, head of marketing at Dr Wolman GmbH, told the company’s annual conference last week.
And ensuring timber’s good reputation was very much the theme of the two-day event. Acknowledging that perceptions of treated timber were sometimes poor, especially recently in the UK where premature fence post failures have hit the headlines, Mr Prager said consistent quality treatment was a means of enhancing timber’s reputation.
To back up this argument BASF Wolman and IVL, the Swedish Environmental Research Institute, have completed a life cycle assessment (LCA) on timber treated with Wolmanit CX-10 according to BS 8417. The study looked at two fence designs in Use Class 4 pressure-treated pine; plastic; and untreated UK-grown European larch and Siberian larch – and found in favour of the treated timber.
Presenting the findings on the first day of the conference, at the BRE, Martin Erlandsson of IVL said the Wolmanit CX-10 treated fence offering a 30-year minimum service life had the best environmental performance, followed by the minimum 15-year service life of Wolmanit CX-10 treated timber with a lower retention.
Incising Sitka spruce
It’s good news for treated timber but in the UK 60% of commercial forest is Sitka spruce, a species that is difficult to treat to BS 8417’s requirement for 6mm penetration for Use Class 4, and so treaters are turning increasingly to incising to improve preservative uptake. BRE and BASF Wolman have undertaken trials on incised Douglas fir, Sitka spruce and larch, and the results are positive.
As part of the trials, a fence of incised spruce was installed in 2005 and "it’s doing well", Dr Ed Suttie, the BRE’s director of timber and materials sustainability, told the conference.
Incising produced a more reliable and uniform spruce product and provided the "feasibility to meet BS 8417".
"The key thing is reliability," said Dr Suttie. "Incising provides uniform penetration and so improved penetration and retention."
The study also showed that moisture content was critical to incising’s efficacy and that 25-30% moisture content was ideal with spruce.
As part of the research, in 2003 interviews were carried out with DIY retailers, fencing companies and preservative manufacturers. The interviews revealed concerns about the appearance of incised material and the added cost of more processing. However, Dr Suttie said that as incised products were clearly identified by the marks on the timber, incising could be an opportunity for promotion.
The industry had to address "market uncertainty and lack of confidence", he said, and quality treated timber could deliver reliability into finished products. The Grown in Britain campaign, aimed at expanding the use of UK-grown timber, was further motivation.
"It’s going to be good for Britain and good for you," Dr Suttie told the audience.
Wolman technical manager Ernst Wormuth said a trial on incised and unincised Sitka spruce posts of 75mm² and 100mm² showed better penetration with incised material.
"From today’s perspective on square sawn timber, incising is the only way of achieving consistent penetration of 6mm on all four sides to meet BS 8417," he said.
Dosing levels
But while incising does improve preservative penetration, it was still important to have the right dosing levels, said Richard Gulland, who is responsible for Wolman’s technical sales in the UK and Ireland.
"We need to push for independent field testing of the relationship between incising and the chemical," he said.
Independent testing, similar to that of the NTR scheme in Scandinavia (TTJ November 12/19, 2012), is something that BASF Wolman has supported for a long time.
"BASF’s position is a quality scheme will help the best products," said head of sales Dr Mihael Boras. "There are many benefits of a quality scheme: it can create market pull; it gives customers confidence; and provides an opportunity to compete against imported products.
"Our industry isn’t very good at marketing treated wood but a quality scheme can be used as a brand," Dr Boras added.
The UK had BS 8417 and the Wood Protection Association’s (WPA) Benchmark scheme but what was lacking was the transparency of third-party auditing and publication of retention levels, he said.
The Benchmark scheme, introduced in 2011, provides third-party assessment of a product’s ability to perform in line with BS 8417. To date, 17 products and product groups using pine, Douglas fir, larch and incised spruce have been certificated.
Third-party product approval
In November the WPA will take its quality assessment a step further when it introduces a third-party product approval scheme for preservatives (TTJ September 21/28). An independent panel will assess manufacturers’ laboratory and field test data and if it is deemed to reflect what the manufacturer is advising treaters then the product will be "WPA approved".
The next phase will allow those that manufacture Benchmark certificated products using a WPA-approved preservative to offer a WPA warranty.
It’s a development that’s welcomed by WJ Components’ Mark Egglestone. Earlier this year the Hull-based treater opened a new facility at the Scotline Terminal in Rochester, which delegates visited on the second day of the BASF Wolman conference.
The Rochester facility is similar to the company’s Hull base, with two high-pressure tanks treating to Use Classes 2, 3 and 4 using Wolman CX.
"We’ve spent time testing samples, which has led to our achieving WPA Benchmark certification, and now we can offer a 10 and 15-year warranty," Mr Egglestone said.
The Benchmark scheme and manufacturers’ warranties helped give customers confidence that treated timber would perform as it promised, said Mr Egglestone, but ideally he wanted retention levels published, as they are under Scandinavia’s NTR scheme.
He also urged the industry to think about how LCAs could be used to underpin the use of treated timber.
