Progress with the revisions to timber-related standards, NZS 3640:2003 and NZS 3602:2003

Powelltown Sawmill Logs

For the past 12 months, two standards development committees have been working on revisions to the timber-related standards NZS 3640:2003 Chemical preservation of round and sawn timber and NZS 3602:2003 Timber and wood-based products for use in building. The committees include representatives from various sectors:

  • timber preservative manufacturers
  • timber auditor interests
  • wood and timber-based product manufacturers
  • the building regulator
  • research organisations
  • regulatory agencies
  • local authorities
  • relevant industry bodies.

NZS 3640:2003 Chemical preservation of round and sawn timber

  • NZS 3640 was published in 2003 and sets out the requirements for preservative treatment for timber to provide protection from decay and insects, and provides identification requirements in the form of six hazard classes. NZS 3640 has been amended five times since it was first published, and the standard is now due for a full revision to reflect changes in practice and materials, such as new treatment applications and engineered woods.
  • As part of the review, a public request for information on new timber treatments and for any proposed amendments to existing treatments was sent out in July 2016.
  • The draft standard will be released for public comment in December 2017.

NZS 3602:2003 Timber and wood-based products for use in building

  • NZS 3602 sets out required specifications to ensure specific building components are sufficiently durable to function for a specified intended life. This standard was published in 2003 and has not been revised since then.
  • As part of the review a call for information on additional timber products was sent out in October 2016 as it was recognised that the standard could include additional timber products such heat-modified timber, non-biocidal modified timber, and wood-plastic composite.
  • We have released the draft standard for public consultation and request comments by 2 March 2018.

Public consultation

  • All draft standards are posted on the Standards New Zealand website. The DZ 3640 and DZ 3602 draft standards are being widely publicised through various channels including the Standards New Zealand e-zine, the Standards New Zealand website, and through key sector organisations.
  • The public consultation drafts are each supported with a briefing document that outlines the key changes to the standards and the rationale for the proposed changes.

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Published in building.