AWPA E12-20 ✓ Most Recent

This test method describes an accelerated laboratory procedure for determining the corrosion rate of metals when in contact with preservative treated wood. The test is not designed to predict absolute corrosion rates, but rather to provide a corrosion rate in comparison to wood treated with a preservative that has known corrosion characteristics. The procedure exposes metal samples between treated wood blocks at set conditions and the corrosion rate in mils per year is calculated from the data. The rate cannot be extrapolated to all possible scenarios. The results obtained with this procedure are highly dependent on procedure variables and the care taken in performing the work, and may not accurately reflect real-world corrosion rates. Important factors include metal specimen preparation (cleaning), environmental exposure conditions, wood moisture content, and post-exposure specimen cleaning. It is critical that wood treated with an appropriate control preservative be included in a test. Comparisons should be made only against wood treated with those control preservatives, with all experimental parameters held constant. A detailed discussion of corrosion test procedure variables is given in NACE Standard TM0169/G31 (Item No. 21200, National Association of Corrosion Engineers, and P.O. Box 218340, Houston, TX 77218). It is recommended that the first-time user consult the NACE standard prior to using this AWPA standard. Additional background material and a general discussion of corrosion testing can be found in Fontana, 1986. This test method is intended to be a screening test. It may also be used to provide information for standardization of protection treatments.