Proposed changes to NZS 3640
23 June 2005
Public Comment Draft to NZS 3640
NZS 3640 Amendment 2
New Clause 3.4.6
MP3640 stated the retentions for the individual actives. For analytical purposes, if the correct percentage of copper was present the required retention was deemed to have been met.
Under the revised standard, only the TAE is given.
Analysing for TAE is expensive and unnecessary.
Analysing for copper only is an effective and cost efficient means of determining retention.
Change to Clause 5.1.3
Also with regard to branding and identification, currently NZS3640:2003 states that timber should be marked with permanent ink, a burn or incision brand or branded with a stapled plastic tag.
Some licensees have encountered operational problems with the staple gun as well as safety issues. They have trialled the use of hot glue and found this method to perform as well as or even better in some circumstances to stapled tags.
They have found:
▪ Adherence to be good even under adverse
weather conditions.
▪ The reverse side of tags are readable as they
do not get torn as in stapled tags.
▪ Speed of application is potentially superior.
▪ Safety is enhanced.
We would like to be able to propose an amendment to NZS3640:2003 that permits the use of glued tags. I know there could be concerns raised about permanence , however we are aware of trials conducted where after two
months there has been no deterioration in the fixing of glued tags or in the glue itself. The tags in question have endured rain and hot, sunny conditions over the months of December, January and February. The glue used has a melting point
of 108o C.
New Clause 5.1.4.1
In New Zealand we have divided H3 into H3.1 for timber in uses where there is no risk of moisture entrapment and H3.2 for timber to be used where there is a risk of moisture entrapment. H3.2 precludes the use of LOSP based preservatives.
In Australia timbers used in a vertical plane and which will have a paint system applied will be branded H3A. Structural timbers will be H3. Australia H3 and New Zealand H3.2 are designed for similar uses but are not entirely identical. Australian H3 will permit LOSP based preservative but this is not permitted in New Zealand H3.2
Retention requirements for the use of other preservatives (water based) for H3 and H3.2 are however almost identical.
Treaters in the interests of flexibility, efficiency and economy would like to be able to produce and brand timber that will be acceptable in both markets. It is possible to treat timber that will satisfy the requirements of both countries but
branding for both markets is a problem. With this in mind we suggest a form of branding that would require SNZ ruling on whether or not it would comply with NZS3640.
Updated Table 6.1
While CuN is included in Table 4.4 - LOSP fungicides - as being approved for use in H1.2, no retention has been specified in Table 6.1. The required retention for CuN should be added to Table 6.1
Updated Table 6.2
The CuN level for H3.1 can be lowered to 0.05 after trials at FRI show it to be effective at this level.
Thye public comment draft can be found in the publications section of this website