Alternatives to CCA for ground contact protection of timber: a perspective from UK on performance and service life expectations

IRG/WP 02-30289

E D Suttie, A F Bravery, T B Dearling

The proposed amendment to the European Union's Marketing and Use Directive (1976/769/EEC) in respect of arsenic in CCA wood preservatives seeks to restrict the use of CCA across the European Union. CCA is an extremely important wood preservative in the UK from the manufacturing of the product to the extent of use of CCA-treated timber. Based on our experience and judgement on the use of CCA and on published literature, there do not appear to be any wholly equivalent alternatives to CCA in terms of cost and effectiveness of performance, particularly under the high hazard conditions of ground contact. This is because, although industry can offer alternative products which are approved for use on the basis of laboratory and indicative field tests, these alternatives are often more costly, behave somewhat differently and do not have the same robust track record of in-service experience. This paper presents a perspective from the UK on arsenic-free alternatives and, using examples of selected results from across the world, estimates the service life performance that the end user might expect. The evidence available indicates that about 2 or 3 times as much CC or CCB is required to give equivalent performance to CCA, 1.5 times as much copper azole and 3 times as much ammoniacal copper quaternary compounds (ACQ). It appears that users cannot expect comparable robustness of performance from the treated wood products and must pay a cost penalty for what is not universally accepted as unequivocal health and environmental gains.


Keywords: CCA, alternatives, Marketing & Use Directive, UK

Conference: 02-05-12/17 Cardiff, Wales, UK


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