With the implementation of the National Construction Code (NCC) 2019 on 1 May, the safety of Australia’s medium-rise residential buildings turned a corner. For the first time, new residential buildings over three storeys and under 25 metres in effective height were required to have automatic fire sprinklers installed, but the requirements also delivered new designs that can make residential buildings both safer and more affordable.
For many years, medium-rise residential buildings had existed in a gap in Australia’s fire protection regulations – too tall to get out of quickly enough in a fire, but without the protection afforded by the sprinklers required by law in taller buildings.
That gap began to appear in the 1960s, when furnishings made of synthetic materials began filling Australian households. Fuelled by these new materials, the rate of fire spread in homes began increasing dramatically.
Testing conducted in Australia and overseas has shown that in a house containing 1950s-era furnishings made of wood, cotton and wool, a fire might take 29 minutes or more to reach the deadly ‘flashover’ point – the complete ignition of combustible materials due to radiant heat.
In an identical house containing modern furnishings made of synthetic materials, however, flashover point is reached in as little as three minutes. Meanwhile, firefighters require an average of 7-8 minutes to arrive on scene and begin fighting the fire.
Clearly, conditions had changed and the existing fire protection regulations no longer provided the necessary level of safety. The tragic consequences of this were seen in 2012 in a fire in a Bankstown apartment block that was not required to have sprinklers installed, and which resulted in the death of one woman and the serious injury of another. A subsequent coronial inquest found both women would have likely survived the fire without significant injury if the building had sprinklers.
Following the inquest, a six-year collaborative project was undertaken by the Australasian Fire and Emergency Service Authorities Council (AFAC), Fire and Rescue NSW (FRNSW), Fire Protection Association Australia (FPA Australia) and CSIRO to develop and propose effective, safe, fit for purpose sprinkler systems for medium-rise residential buildings.
Out of that collaboration have come the new requirements in NCC 2019, as well as two innovative new fire sprinkler designs tailored for medium-rise residential buildings.
New sprinkler requirements
Under NCC 2019, all new Class Two and Three residential buildings four storeys and above and under 25 metres in effective height are now required to have automatic fire sprinklers installed under the Deemed-to-Satisfy (DtS) provisions. These sprinklers must comply with Australian Standard AS 2118.1 or AS 2118.4, as applicable, or two new sprinkler systems designed by FPA Australia and project partners.
With funding primarily provided by FRNSW, the collaboration tested the new sprinkler systems at CSIRO’s North Ryde fire research facility in NSW. These world-leading sprinkler designs, now referenced in NCC 2019 as Technical Specifications FPAA101D and FPAA101H, use innovative features to deliver high levels of protection with reduced cost and complexity.
The effectiveness of these new sprinkler designs was demonstrated in April 2019 with a demonstration burn organised by the Home Fire Sprinkler Coalition, a new partnership between FPA Australia and AFAC. The burn set alight two identical loungeroom mock-ups, one with sprinklers and one without (pictured). In the sprinklered room, the temperature at head height reached 90 degrees before sprinklers controlled the fire. In the unsprinklered room, the temperature hit 1,245 degrees, collapsing the roof and shattering a glass sliding door before firefighters intervened.
The new FPAA101D Technical Specification specifies a sprinkler system integrated with the drinking water supply of a residential building. It provides sprinkler protection throughout the building, and has been designed for use with available Watermark listed products.
Use of the drinking water system significantly reduces cost, while still providing enough water volume for the concurrent operation of the drinking water supply and enough sprinkler heads to maintain tenability at the point of fire origin to provide occupants time to safely evacuate, or until fire service intervention. Because the system is connected to the drinking water supply, water availability is regularly monitored through residents’ use of other water fixtures.
The FPAA101H sprinkler system, meanwhile, is integrated with the conventional wet ‘charged’ hydrant riser, which is already required in the building. This system also provides protection throughout the building, and has been designed for use with available Watermark listed products.
It similarly reduces the cost of the system by combining pipework with the hydrant riser, but also provides suitable protection to maintain tenability to provide occupants time to safely evacuate or until fire service intervention.
Under NCC 2019, when a building is installed with either of these two sprinkler systems, or those specified in AS 2118.1 or AS 2118.4, concessions may be available on other fire safety DtS requirements. The changes reflect the additional tenability time allowed by the sprinklers.
These include increases in the maximum distance of travel to exits and the maximum length of public corridors, and some alterations to external protection requirements and service penetration requirements in internal non-loadbearing walls, among others.
An independent cost benefit analysis considered the different systems and their accompanying DtS requirements, and compared them against NCC 2016 DtS provisions without sprinklers.
The analysis found that for a six-storey hotel test case, total project construction costs would be 1.7% cheaper using FPAA101D compared to current DtS provisions, 3.2% dearer using FPAA101H, and 4.6% dearer using AS 2118.1 or AS 2118.4.
However, what is most important is that an independent fire engineering analysis determined that a sprinkler system reduced the risk level by at least 67% on the current status quo of no fire suppression in Class 2 and 3 buildings less than 25 metres in effective height. As such, the introduction of sprinklers into these homes provides a significant increase to the level of safety of occupants.
“Automatic sprinklers are one of the most effective life protection measures in a fire. This change to our national building rules will dramatically improve the safety of residents living in the 700-plus new medium-rise buildings of this type built each year,” said FPA Australia CEO Scott Williams.
“This is truly a major milestone for all of those involved in this wonderful collaboration, but mostly importantly the community will see the risk of fire in these types of building reduced significantly.”
For more information, go to www.homefiresprinklers.org.au