Preservative Treated Timber
Preservative treatment of timber and wood based products is a process of modifying the natural material with chemicals with the objective of protecting the material in service from attack by fungi which causes decay, by borers and termites.
TYPES OF PRESERVATIVES There are three main types of preservatives 1. Oil-borne preservatives
c. Tanalith T (Permethrin insecticide in a self drying oil carrier such as linseed oil)
2. Water-borne preservatives
(Copper, Chromium, Arsenic) is a multi salt solution the active ingredients of
which are compounds of the elements of copper, chromium and arsenic.
(Ammoniacal, Copper, Quaternary) is a mixture of the compounds of the
elements of copper and quaternary ammonium.
c. Boron type such as that derived from Boric acid or Boric oxide
3. LOSP (Light Organic Solvent Preservative) consists of a solution of a light organic
solvent such as White Spirit mixed with a fungicide and/or insecticide
a. Fungicides such as Tributyltin oxide, Pentachlorophenol, Copper naphthenate and
b. Insecticides such as Cypermethrin, Deltamethrin, Permethrin and Bifenthrin
Treatment Chemicals and Hazard Levels HAZARD LEVEL H1 H2 H3 H4 H5 H6 CREOSOTE Hazard Levels and Applications BIOLOGICAL EXPOSURE SERVICE CONDITIONS
The above is intended to provide general information in summary form. The contents do not constitute specific advice and should not be relied upon as such. Formal specific advice should be sought by members with respect to particular matters before taking action.
IDENTIFICATION Australian Standard AS1604 –Specification for preservative treatment specifies requirements for preservative treatment for sawn and round timber. Any timber claiming compliance with the Standard is required to be permanently marked (branded) to indicate –
1. Preservative code number. A two digit number from 01 to 99
2. Treatment plant number. A three digit number from 001 to 999
3. Hazard class. The letter H followed by a number from 1 to 6. In some cases an additional
• F (associated with H2) to signify an “envelope” treatment suitable for areas south
• A (associated with H3) to signify a lower dose of chemical where the timber will be
further protected by an exterior grade paint system
FIGURE 1 EXAMPLES OF BRAND LAYOUT
1. Various State Forest Departments maintain a register of treatment plants.
2. A list of preservative codes is provided in AS1604 Part 1
The Standard has an optional provision for colour coding to be used in addition to the brand to identify treatment. Timber treated with LOSP and/or envelope treated to H2, H2F or H3 may be colour coded in accordance with Figure 2.
HAZARD BRAND Figure 2 COLOUR CODING CUTTING TREATED TIMBER Specifications for preservative treatment generally require all “sapwood” to be penetrated with chemical but not necessarily all of the “heartwood”. Therefore when a piece of treated timber is docked, checked or drilled untreated timber could be exposed. It is important to preserve the integrity of the treatment by applying an appropriate solution to protect the exposed material. Brush-on treatments, compatible with the different treatment chemicals, are usually available at the point of sale of the timber. HEALTH AND SAFETY Working with treated timber is considered safe provided basic procedures are followed. Recommended procedures for safe handling and storage are explained in material safety data sheets (MSDS) which are available on request at the point of sale or from the producer. Different chemicals have a specific MSDS and can require specific precautions for safe handling, storage and disposal of waste. General procedures involve the use of gloves, eye and respiratory protection and general hygiene such as washing hands after handling and cleaning up sawdust as you work. For further Information - Contact HIA Technical Services1300 650 620
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