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Bushfire Protection Assessment
BlueCare
Grass Tree Court, Sunrise Beach
BUSHFIRE ASSESSMENT REPORT
Grass Tree Court, Sunrise Beach
ISSUE B
June 2008
Client: BlueCare
Prepared by Landscape Architect:
LandGraphics
Landscape Architects and Environmental Planners
Level 2, Esplanade & Second Building, Cotton Tree
Email [email protected]
P.O. Box 18 Maroochydore 4558
Telephone 07 5443 4044
Facsimile 07 5443 4534
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TABLE OF CONTENTS
PROJECT BACKGROUND ................................................................................................................................................ 4
1.0 INTRODUCTION / BACKGROUND INFORMATION ....................................................................... 5
1.1 Background .................................................................................................................................. 5
1.2 Scope of the Report ..................................................................................................................... 5
1.3 Brief Site Description ................................................................................................................... 5
1.4 Existing Vegetation ...................................................................................................................... 6
1.5 Fire Brigade.................................................................................................................................. 8
1.6 Fire Weather ................................................................................................................................ 9
1.7 Fire Run ....................................................................................................................................... 9
1.8 Fire History ................................................................................................................................. 10
1.9 Likely Fire Paths ........................................................................................................................ 10
1.10 Existing Fire Trail Network ......................................................................................................... 11
2.0 BUSH FIRE THREAT ASSESSMENT ..................................................................................................... 12
2.1 Hazard Assessment Methodologies Employed ......................................................................... 12
2.2 State Planning Policy Assessment Methodology....................................................................... 12
2.3 AS3959 Construction of Buildings in Bushfire Prone Areas ...................................................... 13
2.4 Bushfire Modelling ..................................................................................................................... 14
2.5 Qualitative Assessment ............................................................................................................. 17
3.0 RECOMMENDATIONS ......................................................................................................................... 18
3.1 Fire Breaks ................................................................................................................................. 18
3.2 Fire Trails ................................................................................................................................... 18
3. 3 Water Supplies ........................................................................................................................... 19
3.4 Gas and Electricity supplies ....................................................................................................... 20
3.5 Building Construction Standards................................................................................................ 20
3.6 Street Numbering and Identification .......................................................................................... 20
3.7 Internal Roads ............................................................................................................................ 20
3.8 First Aid Fire Fighting ................................................................................................................. 20
3.9 Evacuation Plan ......................................................................................................................... 20
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3.10 Landscaping ............................................................................................................................... 20
4.0 CONCLUSION .................................................................................................................................... 21
APPENDIX 1: DESIGN FIRE ............................................................................................................... 22
Assumptions for Calculations.................................................................................................................. 23
APPENDIX 2: QUALIFICATIONS OF AUTHOR .................................................................................. 24
APPENDIX 3: ADDITIONAL PLATES .................................................................................................. 25
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Project Background
Postal address: Grass Tree Court, Sunrise
Street or property Grass Tree Court, Sunrise
Name:
Suburb, town or Sunrise Beach Postcode: 4567
locality:
Lot/RP no: Lot 1 on SP177650
Local Government Area: Sunshine Coast Regional Council (Noosa)
Type of area: Urban Rural Residential
Type of development: Subdivision no. of proposed lots no. of existing lots
Boundary adjustment Lease which is subdivision
Community title Strata subdivision
Revision History / Document Status
Issue Issue Date Author Checked
(A) Draft for Comment May 2008 Anthony Power
(B) DA Issue June 2008 Anthony Power
Cover: Banksia aemula
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1.0 INTRODUCTION / BACKGROUND INFORMATION
1.1 Background
LandGraphics Landscape Architects were commissioned by BlueCare to prepare a bushfire hazard assessment of Lot 1
on SP177650 (4.66 Ha) and Lot 6 on RP901384 (0.868Ha). The bushfire hazard assessment accompanies a
development application for Material Change of Use of Premises under the Noosa Shire Planning Scheme.
1.2 Scope of the Report
The scope of this report is limited to providing a bushfire hazard assessment and recommendations for the subject
property. Where reference has been made to surrounding lands, this report does not purport to directly assess those
lands, rather it may discuss bushfire impact and / or progression through those lands and possible impact to the subject
property. The bushfire hazard assessment report should be reviewed every 5 years by a suitably qualified person.
1.3 Brief Site Description
The subject site covers an area of 5.528Ha and is accessed via Grass Tree Court, Sunrise. The site is located in an area
of low relief (plain). The Noosa National Park adjoins the site to the west. Burgess Creek flows through the National
Park.
The site contains closed heath and sedgeland. The site has a western aspect ranging from approximately 32m AHD on
the eastern boundary to 15m AHD on the western boundary.
The vegetation and slope has been assessed in four directions for each proposed building envelope. Where appropriate
out from the boundary of the subject land the slope class “most significantly affecting fire behaviour having regard for
vegetation found on it]” for a distance of at least 100m has been determined.
Map 1: Location Map
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1.4 Existing Vegetation
Vegetation is described in map 2 Regional Ecosystems map obtained from the Queensland Environmental Protection
Agency. The predominant vegetation type is Regional Ecosystem 12.2.15 / 12.2.12, 12.2.13 / 12.2.9 and 12.2.5 / 12.2.9.
These regional ecosystems range from healthland / sedgelands to woodland to open forest types. In this regard different
vegetation types will display different fire behaviours when burning. The predominant vegetation type is a mix of tall and
short heathland vegetation.
The full description of the Regional Ecosystems / Vegetation Types is:
RE12.2.15
Coastal sedgeland with Baumea spp., Juncus spp. Lepironia articulata, Gahnia spp. and Eleocharis spp. and associated
water bodies. Occurs on Quaternary coastal dunes and beaches. Low part of coastal landscape where water collects
from both overland flow and infiltration from adjoining sand dunes. Major vegetation communities include: 12.2.15a:
Lacustrine wetland (e.g. lake). Associated permanent water bodies. Occurs on Quaternary coastal dunes and beaches.
Low part of coastal landscape where water collects from both overland flow and infiltration from adjoining sand dunes.
12.2.15b: Palustrine wetland (e.g. vegetated swamp). Lepironia articulata closed-sedgeland. Occurs on Quaternary
coastal dunes and beaches. Low part of coastal landscape where water collects from both overland flow and infiltration
from adjoining sand dunes. 12.2.15c: Palustrine wetland (e.g. vegetated swamp). Cladium procerum closed-sedgeland.
Occurs on Quaternary coastal dunes and beaches. Low part of coastal landscape where water collects from both
overland flow and infiltration from adjoining sand dunes. 12.2.15d: Palustrine wetland (e.g. vegetated swamp). Baumea
rubiginosa closed-sedgeland, with Cyclosorus interruptus and Blechnum indicum. Occurs on Quaternary coastal dunes
and beaches. Low part of coastal landscape where water collects from both overland flow and infiltration from adjoining
sand dunes. 12.2.15e: Palustrine wetland (e.g. vegetated swamp). Leersia hexandra closed-grassland. Occurs on
Quaternary coastal dunes and beaches. Low part of coastal landscape where water collects from both overland flow and
infiltration from adjoining sand dunes.
12.2.12
Closed or wet heath ± stunted emergent shrubs/low trees. Characteristic shrubs include Banksia spp. (especially B.
robur) Boronia falcifolia, Epacris spp., Baeckea frutescens, Schoenus brevifolius, Leptospermum spp., Hakea actites,
Melaleuca thymifolia, M. nodosa, Xanthorrhoea fulva with Baloskion spp. and Sporadanthus spp. in ground layer. Occurs
on poorly drained Quaternary coastal dunes and sand plains. Low part of sand mass coastal landscapes where water
collects from both overland flow and infiltration from adjoining sand dunes. Major vegetation communities include:
12.2.12a: Palustrine wetland (e.g. vegetated swamp). Empodisma minus, Baumea rubiginosa, Epacris microphylla
closed-heathland with emergent low shrubs of Leptospermum liversidgei. Occurs on Poorly drained Quaternary coastal
dunes and sand plains. Low part of sand mass coastal landscapes where water collects from both overland flow and
infiltration from adjoining sand dunes. 12.2.12b: Palustrine wetland (e.g. vegetated swamp). Xanthorrhoea fulva wet
heathland. Occurs on Poorly drained Quaternary coastal dunes and sand plains. Low part of sand mass coastal
landscapes where water collects from both overland flow and infiltration from adjoining sand dunes.
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12.2.13
Open or dry heath. Characteristic shrubs include stunted Banksia aemula and Allocasuarina littoralis as well as
Xanthorrhoea johnsonii, Leptospermum semibaccatum, ,Phebalium woombye, Dillwynia retorta and Caustis recurvata.
Occurs on Pleistocene dunes.
12.2.9
Banksia aemula low shrubby woodland. Mallee eucalypts sometimes present, e.g. Eucalyptus latisinensis. Occurs on
Quaternary coastal dunes and sand plains with deeply leached soils.
12.2.5
Open-forest to low closed forest. Species can include Corymbia intermedia, C. tessellaris, Banksia integrifolia subsp.
integrifolia, B. aemula, Acacia spp., Lophostemon confertus, Callitris columellaris, Livistona spp. and Endiandra sieberi.
Melaleuca quinquenervia in swales. Understorey generally shrubby and can include vine forest species. Occurs of
Quaternary coastal dunes and beaches and sandy banks of coastal streams. Major vegetation communities include:
12.2.5a: Palustrine wetland (e.g. vegetated swamp). Swales dominated by Melaleuca quinquenervia often with Livistona
spp.. Occurs of Quaternary coastal dune swales.
The site vegetation has been ground truthed by PLACE Pty Ltd and found to be present on the site.
Map 2: Regional Ecosystems Map and Place Environmental Vegetation Mapping
Site
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Left: Low Heath / Sedgeland in the
National Park to the west of the site.
Fuel has a high vertical and
horizontal connectivity and is
influenced heavily by wind speed
and direction.
Right: Low to High Heath on sandy
soils. Vegetation has leaves with a
high surface area to volume ratio
and therefore can sustain ignition
relatively easily.
1.5 Fire Brigade
There are two fire brigades located in the immediate area:
• Tewantin Fire Station – located at Hilton Esplanade Tewantin approximately 8.2km from the site
(approx. 16mins to site). This is an auxiliary brigade on 24hour call; and
• Noosa Fire Station – located at Langura Street approximately 2.5km from the site (approx. 5 mins to
site). This is a permanently manned brigade.
Both of these brigades are urban brigades and are therefore professionally manned. They would have
support from Rural Brigades around the coast and probably most notably in this area from Doonan and Tin
Beerwah Rural Fire Brigade. Fire suppression support would also likely to be available from QPWS.
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1.6 Fire Weather
The fire season in South East Queensland is typically from August to November. This is the dry season for SEQ. Strong
westerly winds can accompany bushfire weather during this period. Westerly winds are typically drier winds and
accompany low humidity. In this regard winds from this direction are typically regarded as bushfire winds, though
bushfires will spread under the influence of any wind regardless of its direction where there is fuel to enable its continued
combustion. Fire behaviour and therefore bushfire risk is heavily influenced by weather conditions. Fire weather in
Queensland is typically much less severe than in southern states.
1.7 Fire Run
The length of fire run influences the area in which a fire has to develop and reach its potential maximum intensity for the
conditions at the time of the fire. In this regard it is important to assess the length of fire run to grasp an understanding of
the scale of fires that may be able to eventuate in the area. Fire runs less than a 1km in length may be safely regarded
as having a lesser risk than longer fire runs.
Fire runs may be modified by natural features such as creeks, swampy wet areas, rock formation or wet vegetation
types. They may also be limited by roads, firebreaks or active intervention of fire suppression techniques such as lighting
of backing fires from control lines.
The fire runs in the National Park adjoining the site range from moderate (approx 850m) to large several kilometres to the
south. Fires runs to the west are typically in the vicinity of 1km. The National Park contains several fire trails from which
the fire run may be reduced. Burgess Creek also flows centrally through the adjoining section of park and except for
under high to extreme fire weather conditions would help limit the extent of fire spread.
Fire runs are shown on map 3.
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Map 3: Fire Run Distances
Fire run to NW
approx. 1km
Fire run to W approx
850m
Fire run to SW
approx 1.2km
Approx. location of Burgess Fire run to S
Ck and associated swampy many km
vegetation.
1.8 Fire History
The Noosa Planning Scheme Review: Bushfire Hazard Project included a workshop which included relevant parties such
as fire agencies. At the workshop previous fire history was recorded. The review indicates that fires occurred in the
Sunrise Area in the summer (mid 1950’s), Spring 1965 (1000ha), Spring 1989 (40ha), September 1986 (1570ha),
September 1991 (85ha), December 1992 (10ha), September 1994 (1ha), October 1994 (0.5ha) and 2007. Nine buildings
where burnt in the 1986 fires but not destroyed (Noosa Fire Stn pers comm.).
1.9 Likely Fire Paths
The predominant vegetation and fuel loads are located to the south and west of the site. This vegetation coincides with
the predominant ‘bushfire winds’ which are from the SW to NW. In this regard wildfire approaching the site is likely to
come from these directions. Depending on the dryness of the vegetation, fuel loads and weather at the time of the fire,
the fire path may restricted to one side of Burgess Creek which traverses the National Park. A relatively wide fire front
could develop, especially when wind direction is variable. There is a long fire path to the south, in this regard the western
and southern sides of the development are the most vulnerable to bushfire impact.
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1.10 Existing Fire Trail Network
The Noosa National Park and adjoining Council owned land contain an existing fire trail network in various states of
repair. The fire trail network will be employed as the likely first line of defence by fire authorities in the event that a fire
was approaching the development site. The fire trails would also be used if any prescribed burns were planned. The fire
trails are very important in terms of providing control lines for fire suppression.
The existing network of trails is adequately placed to defend the proposed development. QPWS should be encouraged to
maintain / slash the trail within the National Park prior to each fire season. The fire trail network is illustrated on map 4
below. The development is to be designed to enable continued access to the existing fire trail network. These trails have
been used by the Noosa Fire Brigade in recent times (Noosa Fire Stn pers. comm.)
Map 4: Existing Fire Trail Network
Legend
Site Boundary
Approx. location of existing fire
trails
Grass Tree
Noosa National Park
Dame Patti Dve
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2.0 Bush Fire Threat Assessment
2.1 Hazard Assessment Methodologies Employed
The Noosa Shire Council identifies the subject land as bushfire prone land on Councils Bushfire Overlay. In this regard a
detailed bushfire assessment is triggered.
Various methods were used to determined the bushfire hazard for the site including:
• The methodology described in A3.8 –A3.20 of the SP01/03 Guidelines.
• The site bushfire attack method described in Australian Standard AS3959 - 1999: Construction of buildings in
bushfire prone areas.
• Bushfire modelling for various patches of vegetation on and surrounding the site. Radiant Heat Flux calculations
were made using the View Factor and Liecester Models;
• A qualitative assessment of bushfire attack based on the authors experience.; and
• Discussion with Noosa Fire Station Staff.
All findings were ground truthed.
2.2 State Planning Policy Assessment Methodology
The State Planning Policy Guidelines 1/03: Mitigating the Adverse Impacts of Flood, Bushfire and Landslide includes
guidelines for determining the level of bushfire hazard on a site. The method involves the assigning of ‘loading factors’ for
the various components most likely to influence bushfire hazard including vegetation type, slope and aspect.
A loading of 1 to 5.5 equates to a low severity of bushfire hazard, 6 – 12.5 a medium severity of bushfire hazard and 13
or greater a high severity of bushfire hazard. The predominant fire hazard to the north west to south has been assessed
using this method. Most of the vegetation on the site will be cleared as result of the proposal. In this regard this
vegetation will no longer exist to support flaming combustion and therefore has not been assessed. The remaining
vegetation in the adjoining National Park is the vegetation that will support wildfire. In this regard the vegetation type,
aspect and slope of these areas have been used. The adjoining vegetation within close proximity to the site can be
categorised as Wallum Heath for the purposes of the State Planning Policy. Other vegetation structural types such as
woodland and open forest exist nearby however will not significantly influence the fire hazard to the proposed
development.
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Table 1: SPP Assessment Methodology
Element Adjoining Area of Comment
National Park to the Site
Vegetation Wallum Heath 6 RE12.2.15, RE12.2.13 and 12.2.9 and RE12.2.12.
Community
Slope Plain 0 – 5% 1 The bulk of the vegetation is located under a flat plain.
Dominant Aspect East to South 0 The site has a slight westerly aspect, however the fuel
and all land (vegetation) presenting the fire hazard is flat and therefore has
under 5% slope no aspect.
TOTAL 6 A total of 6 indicates a Medium Bushfire
Hazard
2.3 AS3959 Construction of Buildings in Bushfire Prone Areas
The Australian Standard for Construction of Buildings in Bushfire Prone Areas has its own methodology for the
assessment of categories of bushfire attack. Bushfire attack categories under the Standard include low, medium, high
and extreme. The Australian Standard is currently under review and will include a much more sophisticated method of
assessing bushfire attack class and levels of building construction.
The proposed development has a setback of approx 10 - 15m from the adjoining heathland vegetation. Heathland
vegetation is categorised as Low Shrubs (Group 16 – Closed Heath) and Tall Shrubs (Group 13 - Open Scrub) under the
standard. The slope is rated as less than 10 degrees.
Based on the abovementioned parameters and using Table 2.1 – Determination of Category of Bushfire Attack for a Site,
the category of Bushfire Attack is extreme for building sites within 15m of the tall scrub and high within 15m of the low
scrub. This would necessitate the provision of a level 3 std of construction for extreme sites and a level 2 std of
construction for the high sites.
The existing Australian Standard assessment methodology is now typically regarded as deficient by bushfire experts and
more appropriate methods of determining construction requirements such as empirical bushfire models are available.
The revised Australian Standard will address these issues. The revised std should be released within a year.
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2.4 Bushfire Modelling
Bushfires may be modelled using mathematical modelling techniques.
For heathland vegetation wind speed is a dominant factor in determining fire behaviour characteristics. For planning
purposes a wind speed of 45km/h is generally considered the appropriate (worst case) wind speed for inputting into
empirical models and has therefore been adopted for this assessment. There are two types of heathland on the site – tall
heath to approx 3m in height and low closed heath to 1.5m in height. The tall heath has a higher fuel load and therefore
contributes to higher fire intensities.
The results of the modelling for a credible worst case fire scenario on the property ‘Design Fire’ are summarised below.
The result could be equated to a 1 in 50 year event which is the recognised level of planning recognised as being by the
Australian Bushfire Council. The majority of fires occurring within a 50 year timeframe would not reach the intensity
predicted in this worst case scenario.
Fire behaviour was modelled as potentially being very intense during a credible worst case bushfire weather scenario
and based on the existing topography and vegetation type and extent. The intensity of the modelled fires is such that the
worst case fires could not be directly attacked by fire suppression authorities and a defensive strategy would need to be
adopted. It is therefore important that the proposed development include design attributes which make the development
more easily defendable.
Based on the proposed 15m setbacks from the predominant vegetation the modelled radiant heat for the worst case
scenario is such that direct flame contact with the proposed buildings would not occur. Copies of the modelling results
are included below. Calculation equations and assumptions are included in Appendix 1.
Tall Heath Results
Low Heath Results
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The following graph indicates the radiant heat flux profile of the modelled fire under the 45km/h wind
scenario for the Liecester Model for the low heath which is the predominant vegetation of the National Park.
Radiant Heat Flux Profile (Heathland) using Leceister Model
70
60
Radiant Heat Flux (kW/m2)
50
40
30
20
10
0
Distance from Un-managed Vegetation (m)
2
The resultant radiant heat flux using the Leicester Model at 15m setback (building facade) is 24.64kW/m in
-1
the low heath. The fire line intensity is 23794kW/m which is a very intense fire. Direct suppression with
water is not possible with this intensity of fire.
The radiant heat flux at the building facade would require the provision of a level 2 standard of construction
under AS3959 using the Leicester model for the low heath and level 3 std for the tall heath.
The flame length of the design fire for the low heath is predicted to be 7.99m and 12m for the tall heath. The
proposed setback of approximately 15m is of sufficient distance to not allow flames to directly touch the
proposed buildings.
Use of the View Factor Model for the calculation of radiant heat flux indicates a lower level of incident radiant
heat flux than the Leicester Model. The View Factor Model is the more recent and preferred model among
bushfire practitioners. The incident radiant heat is still such that a level 3 std of construction is warranted
where buildings adjoin the tall heath and a level 2 std of construction where buildings adjoin the low heath.
The modelling results need to be tempered and in reality may be over conservative. The models rely on
determining a number of mathematical variables which are open to conjecture among the bushfire
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community and or are modified by site conditions. Important variables for the design fires include the wind
speed, flame temperature and fuel load.
Wind Speed has been used at 45km/h in accordance with accepted practice, however the heathland is
surrounded by taller forest vegetation which would have a reducing effect on wind speed. The actual affect
on a given day is almost impossible to define. However the presence of these trees would tend to have a
calming effect on fire behaviour in the heathland.
Flame temperature is the single most important factor in determining bushfire setbacks and is being debated
among the Australian Standards Committee for the forthcoming redraft of AS3959: Construction of Buildings
in Bushfire Prone Areas. Flame temperatures of 1090K (816 deg C), 1000K (726.85 deg C) and 910K
(636.85 deg C) are being considered by the committee. There is also recent research including Project Vesta
conducted by the CSIRO that flame temperature varies within the column of the flame itself, with the top of
the flame being the coolest. The change in flame temperature has large implications for the ability of a
building to withstand the incident predicted radiant heat flux. It is the authors opinion that for very intense
fires a higher flame temperature is likely to result. The selection of an appropriate flame temperature for
legislative requirements is under keen debate among the bushfire community.
No detailed fuel accumulation studies have been undertaken for heathland vegetation in Queensland to the
authors knowledge. In this regard fuel loads of 15t/ha (short heath) and 25t/ha (tall heath) have been
selected as used in NSW and accepted by the Australian Standards Review Committee for all of Australia.
On-site visual inspection confirmed that these fuel loads are appropriate. Burning of the vegetation would
have the effect of temporarily reducing the fuel load.
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2.5 Qualitative Assessment
There has been a history of wildfire in the Noosa Area. In this regard it is prudent to plan for bushfire mitigation
particularly where development abuts large areas of flammable vegetation such as National Parks.
Discussion with officers at Noosa Fire Station in June indicated that fires occur in the National Park with frequent
regularity (approx. Every 3 – 4 years) many of which are started by children at the nearby schools. The actual timing of
fires however depends upon the prevailing weather conditions and an ignition source – i.e. something to start the fire and
the weather conditions to sustain it.
The heathland vegetation is comprised of an elevated fuel load that has a high connectivity vertically and horizontally,
low - moderate bark fuel and a low – moderate surface fine fuel. The tall heath around the fringes of the development
has a very high to extreme elevated fuel load. In this regard fire spread across the elevated heath is likely to be rapid
under severe fire weather conditions. Conversely during periods of lower fire danger any fires in the heathland would
pose little threat to the development. Fire behaviour in Heathlands are very susceptible to variations in wind speed and
direction and in this regard fire behaviour can change suddenly.
Heathland vegetation can burn very intensely as the empirical model results indicate. Actual fire behaviour would vary
spatially and temporarily especially in response to local variations in fuel load, fuel structure, fuel moisture content and
wind. The spotting potential of healthland vegetation is less than some other types of vegetation, though spotting could
still be up to a couple of hundred metres in extreme conditions, though most intense for approx. 50m. Spotting would be
the most intense in close proximity to the actual fire front with burning ember density decreasing with further distance
from the front. In this regard there is potential that the development could be impacted by ember attack.
Past fire events in the area and discussion with Noosa Fire Station Officers indicate that firebreaks in the vicinity of 10 –
15m are appropriate to mitigate most heathland fires especially if a fire authority response is deployed to defend the
property under attack. Problems may occur under worst case scenarios where fire behaviour is more severe than the
norm and fire crews are already deployed elsewhere and cannot help protect the development. In this regard bushfire
mitigation must be designed to be able ‘stand alone’ if a fire fighting response is unavailable or delayed.
Under most circumstance a fire fighting response will be available and the likelihood of loss of buildings is considered
very remote in these circumstances. The creation of suitable fire breaks, increasing the resilience of the buildings and
assisting fire authority response (access and water) are all appropriate measures to assist in bushfire mitigation.
The Noosa National Park and adjoining Council land contain fire trails which would allow access to fire crews. The fire
fighting response to intense heath fires is likely to be based on an indirect attack where back-burning methods are used
rather than direct attack with water. Fire fighting response / techniques would be determined by the Incident Controller at
the time of the wildfire.
Escape routes are directly available to the east away from flammable vegetation. Any decision to evacuate the retirement
village would be determined by BlueCare Management in conjunction with Emergency Services. Evacuation would only
likely be required where it was felt that residents would be adversely impacted by smoke or stress.
The construction of the development will have the added benefit of significantly reducing the bushfire hazard to lots 763 –
770 on Columbia and Ben Lexcen Drive.
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3.0 Recommendations
3.1 Fire Breaks
A 12 - 15m wide fire break is to be maintained between proposed buildings and the adjoining predominant vegetation.
The fire break is to be maintained in accordance with the following:
• No tree or tree canopy is to occur within 3 m of the dwelling;
• The presence of a few shrubs or trees in the Inner Protection Area is acceptable provided that they:
• are well spread out and do not form a continuous canopy;
• are not species that retain dead material or deposit excessive quantities of ground fuel in a short period
or in a danger period; and
• are located far enough away from the building so that they will not ignite the building by direct flame
contact or radiant heat emission.
• Any landscaping or plantings should preferably be local endemic mesic species or other low flammability
species;
• A minimal ground fuel is to be maintained to include less than 4 tonnes per hectare of fine fuel (fine fuel means
ANY dead or living vegetation of <6 mm in diameter e.g. twigs less than a pencil in thickness. 4 t/ha is
equivalent to a 1 cm thick layer of leaf litter);
• Any structures storing combustible materials such as firewood (e.g. sheds) must be sealed to prevent entry of
burning debris where these structures are located against the building or within the 15m firebreak; and
• The firebreaks allow unimpeded access all around the dwellings to fire crews and equipment.
Firebreaks proposed (15m) exceed those required in the State Planning Policy (10m). Where the fire break is
accompanied by a stone or block ‘ha ha’ wall as illustrated below the fire break may be reduced to 10m. The effect of the
wall is to block radiant heat and stop the passage of flame as well as reducing the effective flame length. The taller the
‘ha ha’ wall the more effective it will be. The actual height of the ‘ha ha’ will be determined by engineering requirements.
‘Ha Ha’ wall
Source: Adopted from Ramsay & Rudolph. CSIRO Publishing 2003
3.2 Fire Trails
Fire trails are to be constructed which will allow fire appliances to access the western and southern side of the proposed
buildings adjoining the National Park and Council land. An additional fire trail is to be constructed which connects to the
trail off Grass Tree Court. A continuation of access to the existing fire trail network is to be afforded to continue the
effectiveness of the fire trails and prevent the creation of ‘dead ends’ which are dangerous for fire fighters working on
such trails. Important connections are to be maintained (i.e. access for 4WD fire vehicles) as indicated by the orange
arrows on the map below. The development proposal allows for these connections.
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The land to the south of the site is zoned as ‘Community Services’ and it is therefore conceivable that this land would be
developed in accordance with the entitlements of that zone. Should development be undertaken to the south of the site,
a fire trail would no longer be required as a bushland / development interface would no longer result. Similarly the
existing fire trail on the western side of the houses along Ben Lexcen Drive and on the site will be made redundant by the
construction of the development. In this regard this portion of the fire trail will not need to be retained however a
connection to the remaining portion of fire trail will be required as indicated on the map below.
The fire trail on the southern side of the development may be provided on the development side or more practically on
the adjoining Council land. This fire trail will be an important control line to fires approaching the site from the south,
however will also be made redundant when the land to the south is developed. In this regard the trail on the southern
boundary may in reality be a temporary trail.
Legend
Site Boundary
Maintain Connections Grass Tree
Existing Section of fire trail made
redundant
Noosa National Park
Dame Patti Dve
3. 3 Water Supplies
The development will be connected to reticulated water supplies. Fire hydrants are to be located and installed in
accordance with Australian Standards. Fire hydrant locations are to be highlight with standard street marking (yellow
painted icon on kerb and cats eye reflectors).
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3.4 Gas and Electricity supplies
Any gas services are to be installed and maintained in accordance with AS 1596. The relief valves of any gas cylinder
located near dwellings are to be directed away from buildings and away from combustible materials.
3.5 Building Construction Standards
Buildings within 50m of the National Park and predominant flammable vegetation are to be constructed in accordance
with a level 1 standard of construction under AS3959. Buildings directly adjoining retained vegetation on the southern
and western boundaries are to be constructed to a level 2 standard of construction under AS3959. Building construction
standards are to be reviewed at the time of building approval and may be subject to the new Australian Standard for
Building in Bushfire Prone Areas yet to be released.
3.6 Street Numbering and Identification
The new property number should be easily identifiable from the street by emergency crews. Letter box / entry
statements numbers should be large print (greater than 80mm in height) and be made of material which is
reflective and therefore easily identifiable at night.
3.7 Internal Roads
All internal roads are to be able to accommodate an urban 2wd tanker / fire appliance.
3.8 First Aid Fire Fighting
All building blocks (i.e. each group of units) on the western and southern side of the perimeter road are to
have a fire hose reel installed on a convenient and prominent location. The hoses must be of a suitable
length to enable access to all sides of the buildings to extinguish spot fires.
3.9 Evacuation Plan
An evacuation plan for the village is to be developed by the management of the facility in accordance with
best practice and relevant standards. A good guideline for the preparation of bushfire evacuation plans is
available from the NSW Rural Fire Service. Staff are to be trained in what to do in a bushfire emergency and
how to manage residents.
3.10 Landscaping
Landscaping of the development is to be considerate of the requirements for asset protection zones. In
addition no flammable species are to be used directly against buildings and especially windows. Mulches
used adjacent to buildings should be a non-flammable type such as stone. Landscaping should be designed
to avoid the creation of fire paths towards buildings.
3.11 Maintenance
All firebreaks, fire trails and other bushfire mitigation measures are to be maintained to achieve optimum
bushfire mitigation potential. Maintenance guides are available from the Queensland Fire and Rescue
Service and their website. A pre-fire season checklist is to be developed and completed by the operators of
the retirement village each year.
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4.0 Conclusion
In the author’s professional opinion the bushfire protection requirements listed in this assessment provide an
adequate standard of bushfire protection for the proposed development, a standard that is consistent with
the State Planning Policy 1/03.
Anthony Power
Environmental Planner / Bushfire Specialist
References
Caird, R. & Rudolph, L. 2003. Landscape and Building Design for Bushfire Prone Areas. CSIRO Publishing. Collingwood.
Environmental Protection Agency, 2006, Regional Ecosystem Description Database, viewed 7 October, 2006,
http://www.epa.qld.gov.au/projects/redd/index.cgi?reid=12.9-10.14
Noosa Council, 2004, The Noosa Plan, Noosa Council website, www.noosa.qld.gov.au, accessed 1/10/06.
Queensland Government, 2003, State planning policy 1/03 guideline: Mitigating the adverse impacts of flood, bushfire and landslide,
Department of Local Government and Planning, Brisbane
Standards Australia 2000, Construction of buildings in bushfire-prone areas, AS 3959, Second edition 1999 and Amendment 1, 2000,
Standards Australia International Ltd, Sydney
Tan, Z, 2006, Effect of fire run distance on bushfire behaviour and its implications for bushfire hazard rating and prescription of asset
protection zones, NSW Rural Fire Service Technical Paper 002/2006, NSW Rural Fire Service, Sydney.
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APPENDIX 1: DESIGN FIRE’S
Bushfire Design Fire’s for the portion of the surrounding bushland most influencing bushfire behaviour have been
evaluated as part of the bushfire engineering process. The design fire is determined to enable matching of the building
design and material science to the resultant exposure. This included determination of:
• Flame length;
• Rate of spread;
• Fire intensity;
• Radiant heat flux as a function of distance; and
• Radiant heat time profile.
A design fire for the heathlands has been determined. Sensitivity studies were not undertaken for this project. Sensitivity
studies could be undertaken for wind speed and fuel loads. However were not considered warranted as the proposed
Master Plan enables the provision of appropriate bushfire mitigation responses.
Calculations
The following equations were used in determining the following fire behaviour characteristics.
Fire Intensity: McArthur’s Equation I = HWR/36
Rate of Spread: Noble’s Equation R = 0.049*V1.21*VH0.54
Flame Length: Alexander’s Equation Lf = 0.0775*I0.46 (heath)
4
T
Radiant Heat Flux: View Factor Model Qd = φσΤ
e
Where
2 2 2 2 2 2 2
φ = 1/π{ (X /√ 1 + X ) tan-1[Y /√1+ X ] + (Y /√ 1 + Y ) tan-1[X1/√1+ X ] + (X /√ 1 + X ) tan-1[Y /√1+ X ] + (Y /√ 1 + X )
1 1 1 1 1 1 1 2 2 1 2 2 2
2
tan-1[Y √1+ X ]}
1/ 1
-11 2 4
σ = Stefan-Boltzman constant (5.67 x 10 kW/m K )
0
Τ = Temperature of flame ( K).
e
X , Y , X , Y are intermediate variables, which are defined by:
1 1 2 2
X = [Lf (sin α + θ- 0.5cos(α+θ) tan θ) – d sinθ - h]/d cosθ - 0.5 Lf cos (α+θ)]
1
Y = Y = (0.5Wf)/[d cosθ - 0.5Lfcos(α+θ)]
1 2
X = {h+[d cosθ - 0.5Lf cos(α+θ)] tan θ}/{d cosθ - 0.5Lf cos (α + θ)]
2
Where Wf = flame width (m)
α = flame angle (degrees)
d= distance between vegetation and receiver
h= height of radiation receiving point (m) from the ground.
T= transmittance factor
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Assumptions for Calculations
The following assumptions were adopted for quantification of the design fire (credible worst case scenario).
Assumed values are listed below:
Vegetation: Short Heathland & Tall Heathland
Effective Slope (degrees): 1 - flat
Separation Distance (m): 15
Flame Width (m): 100
Flame Angle (degree): 81
Flame Temperature (K): 1090
Flame Emissivity: 0.95
Overall Fuel Load (t/ha): 15 (low heath) 25 (tall heath)
Relative Humidity (%): 25
Ambient Temperature (K): 308
Heat of Combustion (kJ/kg): 18600
Elevation of Receiver (m): 3.82
Fire Run (km): >1km
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APPENDIX 2: QUALIFICATIONS OF AUTHOR
Anthony Power has a Graduate Diploma in Planning and Design for Bushfire Prone Areas from the University of Western
Sydney, currently one of only four people in Queensland with this specialist degree. He is currently the Fourth Officer of
Kureelpa Rural Fire Brigade in the Sunshine Coast Hinterland. He has presented to Local Authorities and the South East
Queensland Fire and Biodiversity Consortium on development in bushfire prone areas. He was also the bushfire
assessment specialist for Maroochy Shire Council from 2005 to late 2007. Anthony also has several bushfire
qualifications from the Queensland Fire and Rescue Service including Certificate 1 in Fire Management and Crew
Leaders Accreditation. Anthony is a member of the Fire Protection Association and is well versed in the practical and
theoretical aspects of bushfire suppression and mitigation. He also has tertiary qualifications in Urban and Regional
Planning, Natural Resources and Horticulture all of which are relevant to understanding bushfire mitigation for new
developments.
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APPENDIX 3: ADDITIONAL PLATES
Top Left: Short Heath
Below: Tall Heath / Woodland
Mid Left: Fire Scars on tree
Bottom Left: Additional Fire Scars
Below: Existing QPWS fire trail in Nat. Park.
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