Chapter 4
I Management Of Native Forests
II Plantations-high Productivity Resources
III Protecting The Resource
IV Harvesting The Resource
V Solid Wood And Its Processing
i Sawmilling
ii Drying
iii Preservation
iv Quality and standards
VI Minor Forest Products
VII Reconstituted Wood Products
VIII Pulp And Paper
IX Export Woodchips
X Future Directions
XI Acknowledgements
References
Index
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Preservation (continued)
Also in 1957 a commercial pressure impregnation plant was successfully established in Melbourne to treat sawn radiata pine with water-borne copper chrome arsenate (CCA), a preservative whose use was well-established overseas and which had been earlier studied in trials in Australia. Pressure impregnation of sleepers and structural timbers with creosote or furnace oil containing preservatives such as pentachlorphenol also became widespread during the late 1950s and 1960s, with plants being established in most States. The Boultonizing process, a UK development, was most commonly used, in which green timber was boiled in creosote or furnace oil under vacuum to displace water and then subjected to conventional pressure treatment. Penetration was often facilitated by first incising the timber. Through the 1960s pressure impregnation plants, both creosote and CCA, proliferated in pace with the rapidly expanding economy and because of the growing awareness of the benefits of treatment, particularly for the increasing quantities of radiata pine then becoming available. By 1961 there were 36 plants operating, today there are about 150. Somewhat more than half their output is hardwood and CCA is by far the most widely used preservative in pressure treatment.Although much of the pressure impregnation technology used in Australia has been overseas-based there have been some notable local innovations. One is the use of very high pressure (7000 kPa instead of the usual 1400) developed by Tamblyn[56] in CSIRO for impregnating heartwood and the denser species. This was introduced commercially in Western Australia in 1960 for treating karri telephone pole cross-arms with pentachlorphenol in furnace oil and has since found other applications. In the early 1970s CSIRO also developed a special CCA formulation designed to prevent fence posts from glowing -and eventually completely burning -after a bushfire has passed through them. This is currently produced by a number of preservative manufacturers and widely used.[57] Another recent innovation is the development and use of pigment emulsified creosote (PEC) arising from a joint project by CSIRO and Koppers Australia Pty. Ltd. This produces cleaner and drier timber surfaces than does conventional creosote treatment which in recent years has caused some health concern amongst workers handling it.[58]
The use of preservatives in light organic solvents (LOSP process) was introduced from overseas in the late 1960s originally as a short dip treatment to protect joinery prior to installation but later developed for double vacuum impregnation to produce a more lasting effect. About 12 plants are now in operation, using a range of treatment chemicals such as copper and zinc naphthenates, tributyltin oxide, pentachlorphenol, dieldrin and aldrin.
Protection of timber against attack by Lyctus borer was an important aspect of CSIR's early research. In the early 1930s Cummins[59] developed an effective boric acid diffusion treatment which, with some variations, is still in use. Other diffusion treatments have also since been developed and used commercially as a result of research by CSIRO and some of the State forest services, for example, sodium fluoride, which is compatible with the phenol-formaldehyde resins used in waterproof plywood, and boron-fluoride-chromium-arsenic (BFCA) patented by CSIRO in 1958.[60] Treatment of many timber products made from Lyctus-prone wood was made compulsory by legislation in NSW and Queensland following the development of the boric acid process.
Organisations in Australian Science at Work - CSIRO Division of Forest Products; Koppers Australia Pty Ltd
People in Bright Sparcs - Cummins, J. E.; Tamblyn, N.
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Australian Academy of Technological Sciences and Engineering |  |
© 1988 Print Edition pages 222 - 223, Online Edition 2000
Published by Australian Science and Technology Heritage Centre, using the Web Academic Resource Publisher
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