scope:

This Standard sets out requirements for the preservative treatment and identification of timber to provide protection from decay and insect attack. This includes marine borers in all likely exposure conditions throughout New Zealand. The requirements are based on hazard classes that are described in this Standard.

The assessment of treatments in this Standard is on an evidential basis for resisting fungal, insect or marine wood borer attack within the prescribed hazard class.

In addition, in this Amendment No. 5 some consideration has also been given to the intended end-use of the treated timber.

The requirements for hazard class H1.1 and H1.2 apply to all species for which hazard class H1.1 and H1.2 is specified in NZS 3602. Hazard classes H2, H3.1, H3.2, H4, H5 and H6 apply only to Pinus species.

Some special requirements are also included for softwood Laminated Veneer Lumber (LVL). Refer to AS/NZS 1604 Parts 2 to 5 with the exception of H1.2 treatment for LVL for which this Standard will apply.

While it may be possible to treat other species using the provisions of this Standard, such treatments are outside the scope of this Standard and the adequacy of the resulting treatments will need to be demonstrated.

For the treatment of hardwoods refer to AS 1604.1. For the treatment of other wood-based products, refer to AS/NZS 1604, Parts 2 to 5.

This Standard is intended for use by treatment plants. Assessment of compliance is to apply at the plant gate.

NZS 3640 is to be used in conjunction with NZS 3602, NZS 3603 and NZS 3604 which are referenced in the New Zealand Building Code (NZBC) Compliance Documents.

NZBC Compliance Document acceptable solution B2/AS1 may reference all or part of a Standard. As this Standard may not be referenced as a complete Standard users need to refer to B2/AS1 for compliance requirements.

The New Zealand Timber Preservation Council (NZTPC) and AgriQuality as examples operate quality control and branding schemes. Further details are given in Appendix A. This Standard does not preclude the adoption of any other appropriate quality assurance schemes which may be introduced in the future.

The effectiveness of preservative treatment can be adversely affected by subsequent handling, storage and utilisation. These issues are outside the scope of this Standard, but some advisory information is given in Appendix B.