Preservative LOSP Treatment
Light Organic Solvent-borne Preservatives (LOSPs) are preservatives that contain combinations of fungicides and insecticides for timbers used in internal and external situations. All of these preservative components are incorporated in a solvent carrier such as white spirit.
LOSP treated timber may retain some of the solvent used in the treatment process for a period of time after treatment. The following precautions should be taken to minimise any potential health effects to users:
LOSP treated timber should be stored in a well ventilated, under cover area with any protective wrapping removed.
Where possible packs should be opened a day or two before use to allow any residual solvent vapours in the inner boards to evaporate.
Preservative CCA Treatment
Structural plywood is generally impregnated to H3.2 hazard class with CCA (Copper Chrome Arsenic) treatment to AS/NZS1604.3:2002. H3.2 hazard class is described as: “outside, above ground, subject to periodic, moderate wetting and leaching”. Refer to the standard for more detail.
CCA waterborne preservative is used for structural plywood. It has a green colour, and is dried following treatment so that the sheets may return to the correct dimensions and are at a moisture content suited to use in building. The fillets used to separate sheets in drying may leave marks on the sheet surface. These fade after a time, and are easily covered with paint but may be visible under stain.
The process of treating with CCA and subsequent drying is likely to increase the face checking of the panel.