Purpose
The project aimed to develop practical methods of preservative and fire-retardant treatments for Tasmanian hardwood species to increase their desirable characteristics.
Summary
This research focused on Tasmanian oak and shining gum, which have no natural fire resistance and very low natural durability, making them difficult to treat using conventional methods and chemicals. The project involved developing preservative and fire-retardant treatments for these hardwoods. Specifically, the goal was to improve the durability of hardwood for use in exterior cladding applications (outside, above ground) and to resist bushfires. The secondary aim was to develop treatment or modification systems for interior linings to improve durability, fire performance, and dimensional stability. Key findings included:
- Veneer treated Tasmanian oak exhibited reliable retentions and penetrations to preservative treatments.
- Vacuum pressure impregnation (VPI) of Tasmanian oak, spotted gum plywood, and veneer materials using fire retardants was successful.
- A novel treatment method was developed for Tasmanian hardwood boards used for exterior wall cladding.
The report recommended further research into the upscaling prospects and commercial value of these novel fire-retardant and preservative treatments.
Benefits for the Forests and Wood Products Industries
The project identified potential alternative treatment options for Tasmanian hardwood species demonstrating potential opportunities for industry, including:
- Treatment of Tasmanian oak veneer-based products that meet the requirements of H3 compliance using VPI in conjunction with other measures.
- Treatment of Tasmanian oak and spotted gum plywood and veneer materials with fire retardant meeting the requirements from Group 1 (interior) and BAL 29 (exterior) using VPI.
- Treatment of seasoned sawn plantation Tasmanian hardwood boards suitable for exterior wall cladding that met the penetration requirements for H3 compliance.
- The thermo-mechanical densification trial found that shining gum and Tasmanian oak could be densified using two different compression ratios, showing no sign of spring back.
Acknowledgement
This work was supported by funding provided to Forest and Wood Products Australia (FWPA) to administer the National Institute for Forest Products Innovation program (NIFPI).
Funding for the program was provided by the Australian Government, the Tasmanian Government and Australian forest and wood products industry.
