14. DD ENV 1099: Plywood - Biological
durability. Guidance for the assessment of plywood for use in different
hazard classes
(Along with BS EN 335 - Definition of hazard classes of biological attack
Parts 1,2 and 3, this voluntary European Standard now contains a U.K.
national annex (informative) covering the application of preservatives
to plywood. This national annex replaces BS 6566 Part 7 : Plywood – Specification
for classification of fungal decay and wood borer attack, the withdrawal
of which becomes effective in April 1999.)
This standard gives guidance on the selection of plywood for use in
the different hazard classes of biological attack as defined in BS EN
335-1.
It covers
- selection
- use of treated plywood
- installation principles
- factors relevant to plywood composition related to biological
durability such as species, sapwood/heartwood, type of adhesive
etc.
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- fungi, insect and marine organisms
See Table 1 of this document.
U.K. National Annex (informative)
This annex provides guidance on the application of preservatives to
plywood where the natural durability of the veneer is inadequate for the
panel’s intended end-use.
Table NA3 summarises the hazard classes as listed in BS EN 335 section
4.2.
Table NA1 refers to the lowest durability class of the veneers. Douglas
Fir and Southern Yellow Pine are both categorised under durability class
4. Read across to the particular end-use hazard class involved and hence
onto the minimum treatment class required, i.e. T1 to T3.
Table NA2 defines the acceptable preservative types applicable to each
treatment class.
Guidance should also be sought from the treating company. |
