Building With Timber In Bushfire Prone Areas Of Australia

1. Are we putting fuel on the fire by allowing the use of timber in bush fire prone areas?

2. Are we missing the point by allowing open sub-floor areas for buildings in bush fire prone areas?

3. How can we adequately address building to building ignitions during bush fire events?

4. Building survivability is not just about getting the construction right in bush fire prone areas: should we also consider landscaping and the on-going maintenance of properties? 

Categories of bushfire

For the residents of Australia, bushy fire is a common thing and bushfires are very frequent in Australia due to hot and dry climate in the months of summer. Every year such bushfires harms the government property and harms the common people of the area in many ways and along with it such fires increase the carbon content in the air and pollute the environment heavily (Smith 2013). It is seen that major fire storms affects heavily and becomes the reason behind many losses of lives and damage of domestic and government property year. Sometimes the losses are so destructive that people give names the day when such things happen like a black Tuesday or Ash Thursday. According to statistics in the year of 2009, a bushfire took lives of 172 individuals and damaged property over 3 million dollars (Cavallo and Ireland 2014). Due to massive bushfires in various areas of Australia, each year massive damages are done to the public and government property, as well as to the wild animals and to the lives of many individuals. Due to these kinds of devastating bushfires many a time’s crops get burnt and that increases the prices of the grains in the market (Whittaker, Handmer and Mercer 2012). The purpose of this report is to highlight that whether the usage of timbers are good or bad near bushfire prone areas and how strategically people can use timber in buildings near bushfire prone areas of Australia.

In Australia, the term bushfire originated from ‘the bush’ meaning relatively sparsely inhabited areas of the land. In Australia people call it bushfire when the fire is uncontrolled and nonstructural that burns the grassy or forest areas of the land and in Australia two main types of bushfires are seen.

The fires in the hilly zones of Australia are generally known as mountainous fire and this occurs especially in the dense forest areas of the nation (Bradstock, Williams and Gill 2012). Mountainous fires are seen in places where the land is less accessible for the individuals and not good for agricultural purposes. In most cases, the steep terrain allows the fire to spread in an uncontrolled way and makes it very hard to stop using other forces by forest department (Smith 2013).

The bushfires that take place in flat grassy lands are generally known as flat fire. These types of fires can move freely triggered by uncontrolled wind. In most cases these fires do not pose many threats as these types of fires are easily controllable and cause lesser harms to life and property (King et al. 2013).

Bushfire prone zones

In Australia there are some states where the chances of bushfires are generally very high and in most cases uncontrollable bushfires are seen in those cases. States like Victoria, New South Wales, Queensland and South Australia are known as bushfire prone zones.

Bushfire prone areas

(Geelongaustralia.com.au, 2017)

If any people reside anywhere in Australia, he or she would definitely be familiar with the term bushfire. Extremely dry and warm weather at summertime leads to extensive bushfire in places of Australia (Whittaker, Handmer and Mercer 2012).  Many a times, the bushfire prone areas are densely populated and whenever a densely populated area gets burnt down to ashes, men rebuild the area and they try to build the place in a way so that the next time fire does not spread in an uncontrolled manner.  One of the most important factors is that people should know that they have to erect buildings in bushfire prone zones in a way so that the building does not catch fire easily (Mannakkara, Wilkinson and Potangaroa 2014). It is not an issue that people cannot use traditional building materials erecting buildings near the bushfire prone zones like timber window or door frames. Individuals can use timber and wood products which were tasted to meet the beaming heat and flame contact requirements of the Australian standard AS 1530.  For an example, Stegbar has a variety of timber windows and doors which are being tasted for the safety reasons and those goods satisfied the Australian Standards to meet the requirements for bushfire attack level (Macindoe and Leonard 2012).

AS 3959 divides bushfire prone areas into six major bushfire attack levels based on the severity of the building’s revelation to ember attack, radiant heat and direct contact of the flames. The categories are provided in this section;

BAL_LOW – very low risks

BAL_ 12.5 – low risk

BAL_ 19 – moderate risk

BAL_ 29 – high risk

BAL_ 40 – very high risk

BAL_FZ – extreme risk (Flame zone)

AS 3959 covers the methodology of determining the BAL for an allotment and further goes on to provide the construction requirements for every level of BAL including the floors, external walls, windows, roofs and many more (Groenhart, March and Holland 2012). Meeting the construction requirements for respective BAL classification the new buildings will meet the requirements of the NCC. The standard focuses on providing specifications for construction materials for each of the six BALs and further provides an alternative of using the materials of constructions that meet the terms with the simulated fire testing provisions according to the Australian Standards AS 1530 (Mannakkara, Wilkinson and Potangaroa 2014).

Bushfire threat

There are seven major bushfire resistant timbers that can be used in the buildings which are near to the bushfire prone zones and those are Blackbutt, Merbau, Red ironbark, Silvertop Ash, River Redgum, Turpentine and Spotted Gum. In NSW building regulations depend from the requirements from the Acceptable Construction Manual within the Building Code of Australia (BCA) which is AS 3959 Construction of Buildings in the bushfire prone zones standards (Whittaker, Handmer and Mercer 2012). While erecting the buildings the organizations need to keep in mind the standards set by the government and in this section those are mentioned.

While building wall enclosing subfloor space, the builders have to use timber framing that is clad with noncombustible materials like fiber cement or bushfire-resistant timbers (Dufty 2012). While building the subfloor that supports pillars, staircases people can use regular timbers. Even building deck and joists and even decking and stair treads they can use either regular timber or bushfire resisting timbers (Bradstock, Williams and Gill 2012). While building the balustrades or handrails the builders must keep in mind those they should use timbers less than 125 mm. While building the external walls the builders has to make with less than 400mm timber and with density of 750kg/m (Fairbrother et al. 2013).

• The builders who erect buildings near bushfire prone zones must follow the guidelines set by the government of Australia (Whittaker, Handmer and Mercer 2012).
• The builders should keep in mind that either they have to make sure that they are using the timbers according to the guidelines set and along with that they have to landscape the gardens of the buildings in a way so that they are able to fight the bushfire to a certain extent (Mannakkara, Wilkinson and Potangaroa 2014).
• The builders must make it sure that the gaps between the boards must be 5mm and the spaces below the deck must be enclosed with bushfire resistant timbers and while sealing the timbers they have to use a non-combustible seal.
• The builders should keep the woodchips and the flammable shrubs away from the edge of the timber deck (Cavallo and Ireland 2014).
• Fire resistant plants and stones are very useful to prevent mild bushfires.
• The builders have to keep in mind that in the buildings there must be ample source of water that could be used to fight the bushfire (Whittaker, Handmer and Mercer 2012).
• The builders must buy moisture and decay resistant timbers for building decks.
• The builders must stock domestic or imported certified hardwoods for erecting buildings (Dufty 2012).

Conclusion

Thus to conclude, it can be said that the builders must keep in mind that if they start erecting buildings they have to use building materials those are certified by the government as per the standards set by the federal government of Australia. It is a fact that government must deploy a department to supervise the buildings near the bushfire zone proactively in order to prevent major damages. Lastly, awareness regarding this issue must be raised among the common people and that would be much more effective. Thus, to summarize the journal, it can be said that using the right building materials and making proper planning of the structures are to be made are the main pillars of preventing the damages from the bushfires.

References

Bradstock, R.A., Williams, R.J. and Gill, A.M. eds., 2012. Flammable Australia: fire regimes, biodiversity and ecosystems in a changing world. CSIRO publishing.

Cavallo, A. and Ireland, V., 2014. Preparing for complex interdependent risks: a system of systems approach to building disaster resilience. International journal of disaster risk reduction, 9, pp.181-193.

Dufty, N., 2012. Using social media to build community disaster resilience. Australian Journal of Emergency Management, The, 27(1), p.40.

Fairbrother, P., Tyler, M., Hart, A., Mees, B., Phillips, R., Stratford, J. and Toh, K., 2013. Creating “community”? Preparing for bushfire in rural Victoria. Rural Sociology, 78(2), pp.186-209.

Geelongaustralia.com.au. (2017). Council Minutes - Section B: Reports - 28 October 2014.

Groenhart, L., March, A. and Holland, M., 2012. Shifting Victoria's emphasis in land-use planning for bushfire: towards a place-based approach. Australian Journal of Emergency Management, The, 27(4), p.33.

King, D.C., Ginger, J., Williams, S., Cottrell, A., Gurtner, Y., Leitch, C., Henderson, D., Jayasinghe, N., Kim, P., Booth, K. and Ewin, C., 2013. Planning, building and insuring: Adaptation of built environment to climate change induced increased intensity of natural hazards. Gold Coast: National Climate Change Adaptation Research Facility.

Macindoe, L. and Leonard, J., 2012. Moisture content in timber decking exposed to bushfire weather conditions. Fire and Materials, 36(1), pp.49-61.

Mannakkara, S. and Wilkinson, S., 2013. Build back better principles for post-disaster structural improvements. Structural Survey, 31(4), pp.314-327.

Mannakkara, S., Wilkinson, S. and Potangaroa, R., 2014. Build back better: implementation in Victorian bushfire reconstruction. Disasters, 38(2), pp.267-290.

McLennan, B. and Handmer, J., 2012. Changing the rules of the game: mechanisms that shape responsibility-sharing from beyond Australian fire and emergency management. The Australian Journal of Emergency Management, 27(2), pp.7-13. 

McLennan, J., Paton, D. and Wright, L., 2015. At-risk householders' responses to potential and actual bushfire threat: An analysis of findings from seven Australian post-bushfire interview studies 2009–2014. International journal of disaster risk reduction, 12, pp.319-327.

Smith, K., 2013. Environmental hazards: assessing risk and reducing disaster. Routledge.

Whittaker, J., Handmer, J. and Mercer, D., 2012. Vulnerability to bushfires in rural Australia: A case study from East Gippsland, Victoria. Journal of Rural Studies, 28(2), pp.161-173.

Whittaker, J., Haynes, K., Handmer, J. and McLennan, J., 2013. Community safety during the 2009 Australian ‘Black Saturday’bushfires: an analysis of household preparedness and response. International journal of wildland fire, 22(6), pp.841-849.