AS/NZS 1605.3:2018 pdf free download.Methods for sampling and analysing timber preservatives and preservative-treated timber - Part 3: Analysis methods for determination of preservative retention. This Standard specifies analysis methods for determining preservative retention in preservative-treated wood products. The calculations necessary for determining compliance with the requirements specified in the AS/NZS 1604 series and NZS 3640 are outlined. 1.2 APPLICATION This...