Recommended treatment quality levels for rounded spruce products have been increased in the revised draft of BS 8417 Preservation of Timber Recommendations.
The draft, which is released for public consultation, recommends that acceptable quality levels (AQL) for rounded resistant timbers such as spruce are increased to 10%. The AQL for sawn resistant timbers remains at 25%, while timbers classed as permeable stays at 1%.
The Wood Protection Association (WPA) said treaters of round resistant timbers will need to ensure the higher quality level is being achieved.
WPA director Steve Young said the input of WPA members into the revision process had been invaluable.
“The frontline experience of WPA treaters with the newer wood preservatives has been particularly relevant in parts of this revision concerning those species classed as resistant to treatment like spruce,” he said.
The release of the revised standard draft follows some reports of early failures to spruce rounded fence posts treated with newer wood preservatives.
Mr Young urged members to consult preservative suppliers to verify the changes needed to ensure continuing compliance with the new standard.
He also confirmed that standard compliance and an audit of operating regimes of individual treatment plants would form the basis of a treated wood quality scheme to be introduced by the WPA in collaboration with leading wood treaters in early 2011.
The revision will replace both the previous versions of BS 8417 2003 and A1 2007, as well as BS 1282: 1999.
The WPA campaigned for the new standard to be easier to interpret than existing standards.
Consultation expires on December 31 and publication of the revised standard is expected in the first half of 2011.
