NZS 3640 Amendment 3
19 September 2006
NZS 3640 Amendment 3
Following protracted consideration, including an independent report and recommendation from an overseas expert, Standards New Zealand have approved Amendment 3 to the timber treatment standard, NZS 3640.
The amendment will permit:
The use of boron at a retention of 0.8% BAE in H3.1 subject to the timber being primed at the treatment plant.
The use of LOSP copper naphthenate at a retention of 0.05% in H3.1.
Timber treated to H3.1 is used as:
External products where there is no risk of water entrapment such as fascia weatherboards and external joinery.
Structural members in situations where there is a risk of periodic wetting such as in enclosed balcony framing and enclosed flat roof framing.
Note there is no pre-priming requirement for the LOSP copper naphthenate. However, NZS 3602, which is the standard covering the use of timber in building, requires H3.1 Radiata Pine weatherboard and exterior finishing timbers to be protected with a well maintained three-coat paint system (this includes priming of all faces including cut ends prior to fixing).