NCC 2019 now requires all new Class 2 and 3 residential buildings with a rise in storeys of four or more (and an effective height of 25 metres or less), to have automatic fire sprinklers installed under the Deemed-to-Satisfy (DTS) provisions.
Specifically, Table E1.5 of Volume One has been amended to include these buildings among those which require sprinkler protection. Specification E1.5 has also been amended and a new Specification (E1.5a) has been incorporated to detail the requirements of these systems, as well as concessions that are available for buildings which have sprinkler protection.
In NCC 2019, a Class 2 or 3 building with a rise in storeys of four or more (and an effective height of 25 metres or less) is to have a sprinkler system as detailed in FPAA101D, FPAA101H, AS 2118.1 or AS 2118.4. The type of system that may be used is dependent on a number of building features. In every circumstance, concessions are available which are appropriate on account of the reduced severity of a sprinkler controlled fire.
These concessions include increased distance of travel to exits, internal hydrant omission and some Fire Resistance Level reductions for certain building elements.
FPAA101D Technical Specification
The new FPAA101D Technical Specification details a sprinkler system which draws water from the drinking water supply of a residential building. It provides sprinkler protection throughout the building, and has been designed for use with available WaterMark certified products.
Use of the drinking water system significantly reduces cost. The system specification has been designed to provide enough water volume to sprinkler heads in order to achieve safe evacuation and assist with fire service intervention. Because the system is connected to the drinking water supply, water availability is regularly monitored through residents’ use of water fixtures.
FPAA101H Technical Specification
A system built to the FPAA101H Technical Specification draws water from the conventional wet ‘charged’ hydrant riser, which may already be required in the building.
System cost is reduced by combining pipework with the hydrant riser, yet suitable protection to promote safe evacuation is achieved.
Why the changes?
The changes are the outcome of a collaborative project between the Australian Fire and Emergency Service Authorities Council (AFAC), Fire Protection Association Australia (FPAA) and Fire and Rescue NSW (FRNSW) to develop and propose effective, safe, fit for purpose sprinkler systems for medium-rise residential buildings. The project followed the recommendations of a coronial inquest into a fatal 2012 fire in a Bankstown apartment block, which was not required to have sprinklers installed.
With funding primarily provided by FRNSW, the collaboration tested the new systems at CSIRO’s North Ryde fire research facility in NSW. These world-leading sprinkler designs use innovative features to deliver high levels of protection with reduced cost and complexity.
How these changes were considered
An independent cost benefit analysis considered the different systems and their accompanying concessions, and compared them to a hypothetical building without sprinklers, designed in accordance with the NCC 2016 DTS Provisions. The analysis found that for a six-storey hotel test case, total project construction costs would be 1.7% cheaper using FPAA101D (compared to NCC 2016 DTS Provisions), 3.2% dearer using FPAA101H, and 4.6% dearer using AS 2118.1 or AS 2118.4.
However, more importantly, independent fire engineering analysis determined that a sprinkler system reduced the risk level by at least 67% for a Class 2 or 3 building (less than 25 metres in effective height) without sprinkler protection. As such, the introduction of sprinklers into these buildings provides a significant improvement to the safety of occupants.