A timber component may need extra protection through a preservative treatment depending on its application and natural durability. Wood preservatives enhance resistance to fungal decay and wood-boring insects for timber species that naturally do not have high resistance enabling the product to achieve a longer service life.
Potential requirements for testing include testing fence posts for fencing contractors who want to check if the wood they buy has been appropriately treated; we frequently get involved with fencing, timber-crib retaining walls and external joinery that have failed prematurely in service.
What is timber preservative testing?
Industrial wood preservation has two main facets: penetration and retention, which must be achieved to provide effective treatment to the required level.
Specifying a suitable treatment level and application method depends on the wood's end use and the desired service life. The most effective treatment method is pressure impregnation of the timber preservatives. 'BS 8417:2011+A1:2014 ‘Preservation of wood. Code of practice’ refers only to pressure impregnation methods.
Other common methods include dip treatments and surface brush or spray treatments, although these tend to be more superficial and don’t achieve the required penetration.
Timber Preservative Testing With BM TRADA
BM TRADA offers timber preservative testing of treated wood using test methods and protocols from relevant British and European Standards to establish whether treatment levels in wood samples have been met at the time of treatment. We test freshly treated wood or wood that has failed in service. This is a laboratory-based qualitative and/or quantitative analysis.
Qualitative Timber Preservative Testing
Our team utilise colour reagent testing to establish the depth of penetration of the preservative. The colour reagent solutions used are outlined in BS 5666-2: 1980 'Methods of analysis of wood preservatives and treated timber, Qualitative Analysis'. Penetration requirements for the different levels of treatment are prescribed in the 'BS 8417:2011+A1:2014 Preservation of wood' Code of practice.
Quantitative analysis of Timber preservatives
Quantitative analysis determines retention levels in the analytical zone by examining the proportion of chemicals retained by the wood after treatment. This is reviewed through ICP-OES (inductively coupled plasma–optical emission spectroscopy).
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Wood based product testing
Find out more about our testing of the properties and uses of wood and wood-based products, structural and non-structural.