Treated Timber Specifiers Guide
In Australia, there are a number of different timber preservatives produced by Koppers. Each type of preservative can treat timber destined for different applications, however, the way the timber is treated will vary accordingly. To ensure that the correct treatment type and level of treatment is used in an application, a system of Hazard Classes is used according to the definitions in Australian Standards as shown in the document below.
The higher the Hazard Class, the more severe the exposure is, therefore, it is important to purchase preservative treated timber to the correct Hazard Class irrespective of the preservative type. This means you need to specify the correct Hazard Class for a particular application and ensure that this is marked on the timber that you purchase or your builder uses. There are some restrictions on use of CCA (Copper Chrome Arsenate) in decking and associated posts and handrails, picnic tables, playground equipment and the like, see
The treatment guide below, will assist you to determine the correct Hazard Class for the preservative treated timber in your application. Simply download the PDF below.
Notes:
- Examples shown in this document are not exhaustive.
- It is recommended that specifiers nominate the minimum hazard class level appropriate to the specific exposure and service conditions.
- Extract from AS1604.1, Specification for preservative treatment© SAI Global.