AS/NZS 1604
Joint Australian and New Zealand Standard family for preservative-treated wood-based products, defining hazard classes H1 to H6 and required chemical retentions.
Specification for preservative treatment, published in multiple parts covering sawn and round timber, plywood, reconstituted wood-based products, and LVL. The standard defines six hazard classes from H1 (interior, dry) to H6 (marine immersion) and prescribes the minimum chemical retention and penetration for each approved preservative system, including CCA, ACQ, copper azole, and LOSP. It also sets the requirements for branding, end-tagging, and quality assurance by treatment plants. For buyers, the end-tag is the definitive proof of treatment level: it states the hazard class, preservative type, and treatment plant ID. Always check that the tagged hazard class matches the application; reject untagged or mistagged product, and do not rely on colour alone since some treatments have similar tints.
Values and references on this page are indicative and drawn from common industry sources. Always verify the current AS/NZS standard, manufacturer data sheet or NIAA policy publication before relying on figures for design, specification or compliance work.
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