scope:

This method describes procedures for the evaluation of depletion of wood preservative formulations from treated wood materials used in exterior exposures and above ground. The method is applicable to solid wood, plywood, laminated veneer lumber, and wood-based composites. The procedures may be described by the term "above ground depletion tests". This test is most useful when conducted in parallel with a standard decay test method.

In its most basic form the tests expose treated wood-based samples to natural rainfall and other moisture conditions in field test exposures. The concentration of active ingredients in these exposed samples are then periodically compared to those from unexposed retained samples. Two general procedures are described in detail that can be used alone or in combination with Standardized AWPA above ground and ground proximity test methods. One or more methods may be selected depending on the type of exposure for which the depletion data are desired. The two basic methods described are: (Method 1) wood-based samples exposed in an above ground or ground proximity exposure where each individual exposed sample has an end-matched, unexposed retain sample for depletion comparison; (Method 2) multiple woodbased samples are exposed for each analysis time period, with each sample analyzed once after a specific exposure period and compared against similar unexposed retain samples treated at the same time. Results will not be directly representative of expected depletion rates in commercial products, but will provide relative data compared to standardized systems that are known to be effective treatments under the same exposure conditions. The requirements for preparation of the material for testing and the test procedures appear in the following sections: