Australia is a land of contrasts, and the occurrence
of natural disasters such as bushfires and floods at the same time in
different parts of the country emphasize that this is a nation that is
at the mercy of its environment. It is somewhat ironic that, in the last
days of 2009, while floodwaters inundated vast areas of land in New
South Wales on the east coast, severe bushfires destroyed approximately
40 homes in Western Australia.
It was during the early part of 2009 that
the impact of perhaps the most significant natural disaster in
Australia's history affected the way that Australians live within their
environment. On Feb. 7, 2009, 173 people perished in Victoria as a
result of bushfires - the "Black Saturday" bushfires - that swept across
It is a tragic fact that a disaster such
as the Black Saturday bushfires becomes the catalyst for change. In the
case of the State of Victoria, the circumstances surrounding the
bushfires are the subject of examination by the 2009 Victorian Bushfires
The Royal Commission (the Commission) is an administrative
inquiry established by the Victorian Government on Feb. 16, 2009, to
independently and publicly examine and provide recommendations for the
involvement of the government or its agencies in an event such as the
Black Saturday bushfires.1
Fifty-one recommendations were made by
the Commission in its first interim report, which was published in
August 2009. Those recommendations dealt mainly with actions to be
implemented prior to the commencement of the 2009-10 bushfire season and
The manner in which bushfire warnings
are issued and the development of a new fire severity scale to identify
the risk posed by bushfires;
The provision of information during bushfire
events and arrangements for multi-agency sharing and use of bushfire
Arrangements to facilitate the ability for households or
communities to relocate during bushfires, including amendments to
operational policies of fire authorities to assess and recommend early
relocation when warranted;
The provision of advice by fire authorities -
via a "stay or go" policy - that not all homes are defendable in all
circumstances and that the safest option is to leave early rather than
to stay or defend;
The progressive identification, establishment and
advertisement of designated community refuges, with priority given to
areas where bushfire risk is identified as high;
In order to avoid confusion in relation
to incident management, the development of procedures by agreement
between the fire authorities to ensure that the most experienced,
qualified and competent person is appointed as Incident Controller for
The requirement for the State to settle the higher level
emergency management and coordination arrangements that are to apply
during the bushfire season;
The encouragement of coordination between the
Commonwealth and States/ Territories to ensure the rapid and effective
use of Commonwealth resources during bushfire events, including the
potential for resources to be used to detect, track and suppress bushfires.
A NEW STANDARD FOR CONSTRUCTION OF BUILDINGS IN BUSHFIRE-PRONE AREAS
One important regulatory change that
pre-empted the interim recommendations of the Royal Commission concerned
the construction of buildings in bushfire-prone areas.
Australian Standard 3959, "Construction of Buildings in Bushfire-prone Areas,"2 was
published in 2009, approximately one month following the devastating
Black Saturday bushfires. The new standard was adopted by the Victorian
Government, via amendments to the Building Regulations 2006,3 on March 11, 2009.
The March 2009 amendments to the
regulations related to residential buildings (or residential parts of
buildings) including single dwellings, duplexes, boarding houses, guest
houses, hostels (or the like), residential flat buildings and
residential parts of buildings such as hotels, motels, schools,
healthcare buildings and detention centers. The amendments also relate
to non-habitable buildings associated with residential buildings, for
example, private garages and sheds.4
From a legislative point of view, the
buildings covered by the amendments to the Building Regulations are
those identified as Class 1, 2, 3 and 10a buildings for the purposes of
the Building Code of Australia (BCA).
The BCA details provisions for the design
and construction of buildings and other structures in Australia.
Australian Standard 3959-2009 is referenced in the 2010 edition of the
BCA, which came into force as of May 1, 2010.4
AS3959 contains cautionary notes to
advise that compliance with the requirements of the standard do not
guarantee survival of a building. In Section 11 (Scope), the following is noted:2
this Standard is designed to improve the performance of buildings when
subjected to bushfire attack in designated bushfire-prone areas, there
can be no guarantee that a building will survive a bushfire event on
every occasion. This is substantially due to the unpredictable nature
and behaviour of fire and extreme weather conditions.
The objective of AS3959 is to prescribe
particular construction details for buildings to reduce the risk of
ignition from a bushfire while the fire front passes.
AS3959 identifies a "bushfire-prone area"
as "an area that is subject to, or likely to be subject to, bushfire
Importantly, AS3959 only applies if the site and building are
located in a designated bushfire-prone area as defined by the BCA. The
BCA defines "designated bushfire-prone area" as:4
land which has been designated under a power of legislation as being subject, or likely to be subject, to bushfires.
What is, or is not, land within a
"designated" bushfire-prone area varies between virtually every state
and territory within Australia. In Victoria, the March 2009 amendments
to the Building Regulations apply to the effect that a reference in the
standard to a bushfire-prone area or a designated bushfire-prone area is
a reference to the whole of Victoria. AS3959, therefore, applies to the
entire State of Victoria and a site-specific assessment should be
The process of determining construction requirements for the
purposes of AS3959 requires an initial determination to be made as to
the Bushfire Attack Level (BAL) for the particular building. This
determination is made via an assessment of the site (of the building)
and the vegetation impacting the site.
There are six BALs identified by AS3959,
based upon heat flux exposure thresholds. An abridged version of Table 31 from AS3959 is reproduced in Table 1,2 which describes the predicted bushfire attack and levels of exposure for each BAL.
While not discussed in more detail here,
AS3959 provides two methods for the determination of the BAL: a
simplified procedure or a detailed procedure.
One of the key features of AS3959 is that
the standard seeks to prescribe a deemed-to-satisfy solution for any
building built within 100 meters of vegetation that is identified as a
bushfire hazard. This has also been one of the main criticisms of the
The adoption of AS3959 was opposed by two significant
stakeholders on the FP-020 committee, Australasian Fire and Emergency
Service Authorities Council (AFAC) and the Commonwealth Scientific and
Industrial Research Organisation (CSIRO). The main reason for the
opposition of AFAC, in particular, was that organisation's belief that
there are serious flaws in the new standard. The clear message from the
opposition to the adoption of the standard is that construction
standards in bushfire-prone areas need to be much tougher.5
The reasons for AFAC's opposition included: 6
- Provisions for construction in the flame zone (highest level of risk) -
any home/building that is being constructed in these areas (flame zone)
needs an individual assessment and needs to be individually designed to
the specific fire risks the property faces.
- Gaps -
the new standard specifies gaps to be up to 3 mm (or of an unspecified
size if sarking is used behind the gap), allowing for a much greater
likelihood of ember ignition of roof cavity, wall cavity and the
occupied spaces within the house. Sarking (or, more specifically,
sarking-type material) is defined by the BCA as "a material such as a
reflective insulation or other flexible membrane of a type normally used
for a purpose such as water proofing, vapor proofing or thermal
- Test methods -
there are reservations about test methods identified by the standard
for determining the performance of components under bushfire conditions.
- Subfloor requirements for BAL 12.5 and BAL 19 -
the new standard has no requirements for subfloors or to prevent the
spread of fire from adjacent decks into the subfloor of the building.
- Grasslands - the new standard provides no requirements for this fuel type.
- Issues relating to doors, windows, shutters and wall barriers.
- Egress - no consideration of requirements for the egress path or destination.
- No provisions for ongoing maintenance - to ensure compliance to the standard for the life of the building.
The issues relating to construction in
the flame zone, gaps (aperture size of window mesh and perforated
sheeting), test methods, subfloors, grasslands, doors, sarking-type
material and glazed elements are identified in the Preface to AS3959 as
being issues that are likely to be reconsidered by the FP-020 committee
for inclusion in a future edition of the standard or as amendments to
the standard. The preface to AS3959 also notes that the committee will
review the standard, including construction in the flame zone, following
the outcomes of the 2009 Victorian Bushfires Royal Commission.2
PRIORITIES FOR BUILDING IN BUSHFIRE-PRONE AREAS
The second interim report of the 2009 Victorian Bushfires Royal Commission - Priorities for Building in Bushfire-Prone Areas - was published in November 2009.
The commission's second interim report
contained seven additional recommendations, with specific reference to
the commission's terms of reference, which require it to "consider and
make recommendations on the fireproofing of houses and other buildings,
including the materials used in construction".7
In relation to AS3959, the commission
heard evidence in relation to several issues relating to the standard,
The apparent weakening of the intent of
the standards via a combination of no requirements for subfloor
materials and the allowance of grassland fuels right up to the
Key concerns regarding the use of sarking-type material
behind wall cladding, effectively as a secondary ember-protection
measure, in the absence of any definitive testing of such material to
determine its performance as an ember barrier;
Concerns that AS3959 provides for a
lesser level of ember-protection measures for BAL 12.5 and BAL 19 in the
areas of subfloors and material prescriptions for doors, windows and
wall barriers (than the 1999 version of the standard).
The recommendations made by the commission in its second interim report7 included amendments to AS3959 to:
address the inclusion of unmanaged
grassland in the vegetation types and classifications, and use of
sarking as a secondary ember-protection measure; and
increase ember-protection measures at
lower Bushfire Attack Levels, in particular in relation to subfloor
requirements and materials prescribed for doors, windows and wall
In the meantime, recovery and rebuilding efforts are well under way.
The first interim report of the Royal
Commission noted that in excess of 2,200 homes were lost during the
Black Saturday bushfires on February 7, 2009.1
The rebuilding process is a key part of
the recovery of individuals, families and communities affected by any
natural disaster, especially one of the scale and intensity of the Black
It is apparent that the publication of AS3959, and its
subsequent adoption in Victoria via amendments to the Victorian Building
Regulations, was intended to clear the way for the rebuilding process
to commence as soon as possible after the devastation of Black Saturday.8
The process has not been without its problems, however.
The issues identified by stakeholders in
relation to the standard, particularly those in relation to provisions
for construction in the flame zone (that is, those buildings assessed as
being subject to BAL-FZ) have translated to delays for rebuilding.
A significant criticism of authorities
has been that rebuilding efforts are being hampered by bureaucratic
delays and an obsession with process.9 The criticisms have
seized upon the perception that there does not appear to be any defined
policy from regulators as to how to deal with issues with building in
the flame zone. As a result, rebuilding has been slow due to the
continued disagreement of how to deal with houses identified as being
subject to BAL-FZ under AS3959.
The challenges facing those wishing to
rebuild have been acknowledged by the Victorian Bushfire Reconstruction
and Recovery Authority (VBRRA). A key contributing factor to delays in
plans for rebuilding has been identified as a lag in terms of the
availability of building materials that are approved as being suitable
for use in BAL-FZ situations.5
The issues relating to the unavailability
of building materials have been most prevalent in terms of requirements
to install bushfire (proof) shutters or fire-rated window systems10 in BAL-FZ situations.
The VBRRA identified the availability of
an increased range of BAL-FZ-compliant materials as helping to reduce
delays in rebuilding efforts.5
Cost is another significant issue for
those people seeking to rebuild their homes. Anecdotal evidence suggests
that the costs associated with achieving the construction requirements
for buildings proposed to be rebuilt in the most extreme bushfire areas
could amount to an additional $22,000 (AUD) for fire safety measures on
top of the usual construction costs.8
While the State Government has indicated
that the Victorian Bushfire Appeal Fund was likely to make some funds
available to help compensate for rebuilding costs, there has been no
decision to commit the fund to meeting all of the extra expenses for the
bushfire victims relating to the achievement of the additional
construction requirements of AS3959-2009.8
The Royal Commission plans to deliver its
final report by July 31, 2010, on its investigations of the causes and
responses to the bushfires that swept through parts of Victoria in late
January and February 2009.
The recommendations made in the commission's final
report will be intended to minimize the likelihood of a recurrence of
the tragedy of February 7, 2009.1
A review of AS3959 following the release
of the commission's final report will have the benefit of the
commission's findings and recommendations to assist in shaping future
editions of the standard.
Simon Carroll is with Australian Bushfire Assessment Consultants.
- Interim Report, Victorian Bushfires Royal Commission, Melbourne, Australia, 2009.
Australian Standard 3959, "Construction
of buildings in bushfire-prone areas," Standards Australia, Sydney,
- (Victorian) Building Regulations, Building Commission, Melbourne, Australia, 2006.
- Building Code of Australia, Australian Building Codes Board, Canberra, Australia 2010.
- Blundell, L. "Rebuilding After the Bushfires," The Fifth Estate, 17 December 2009.
- Llewellyn, R. "New AS:3959 Building in Bushfire-Prone Areas," kw news, Australian Fire and Emergency Service Authorities Council, East Melbourne, Australia, March 2009.
- Interim Report 2, Victorian Bushfires Royal Commission, Melbourne, Australia, 2009.
- Rood, D. & Dowling, J. "Bushfire Rebuilding to Cost Victims $22,000 Extra," Stock & Land, March 8, 2009.
- Bachelard, M. & Beck. M. "Bushfire Rebuilding a Failure," Stock & Land, May 2, 2010.
- Draper, M., "Bushfire Rebuilding Is a Pain: Resident," Sydney Morning Herald, August 24, 2009.