AS2419.1: 2021 – Understanding the latest updates to fire hydrant system standards
The 2021 version of AS2419.1 introduces significant improvements in designing, installing, and commissioning fire hydrant systems that was introduced on the 1st of May 2023.
A. Large Warehouses and High-rises are No Longer in Scope
Preface (ii). AS2419.1:2021 excludes buildings with an effective height of greater than 135m, warehouses (Class 7b and 8) with a total area greater than 108,000m2, and warehouses with automatic racked systems. These systems are discussed in informative Appendix D, C and C respectively.
B. Proving the Reticulation Main Residual Supply Pressure Method
22.214.171.124 Reticulation main as a sole supply
- The Utility or “A Party” shall determine that the main is adequate to provide unassisted flows and pressures under 95th percentile conditions.
- If the utility has a calibrated model that accurately determines the friction loss, background demand and network boundary conditions under 95th percentile conditions, then, the supply residual pressure is determined using that utility model. Otherwise,
- The supply residual pressure is determined using the static pressure from the uncalibrated utility model in combination with field measured friction losses. Otherwise,
- As a tertiary option the residual pressure can be determined using a utility approved calculation/method.
C. Booster Changes
7.2 Changes to when a booster is required
A booster is now required when more than 2 feed hydrants are required to provide coverage. This replaces the “more than 6 external hydrants” requirement.
7.3.1 Booster Location
- The booster is preferentially located in the façade of the building and within 20m of the main pedestrian entrance.
- If it’s in the façade of the building but further than 20m from the main pedestrian access then the booster requires a red strobe light which is activated by the smoke detection and/or sprinkler systems.
- If the booster is remote from the building then it is has to be either, located at the property boundary main vehicle access and able to be seen from the main pedestrian entrance, or, within 20m of the main pedestrian entrance and within 20m of the façade of the building containing the main pedestrian access and able to be seen from the main pedestrian entrance.
- If there are multiple buildings with internal hydrants then each requires its own booster cabinet. Alternatively, a single booster located at the principle vehicle access at the site boundary can serve every building.
D. Hydrant Flow Rate Changes
Table 2.2.5 (B)&(C) Reduced carpark flow requirements
The number of flowing outlets for open deck carparks (Class 7a) is now based on the size of the largest storey, not the largest fire compartment. This reduces the size of the fire compartment for multilevel open deck carparks. Previously the openings formed by vehicular ramps between storeys connected the fire compartment for each floor area.
Table 2.2.5(B) Reduced hydrant flow rates in a sprinkler protected building
Buildings less than 25m high with a fire compartment floor area of less than 1000m2 now require 1 flowing outlet. This is only a reduction for Class 6, 7 and 8 buildings and Class 2, 3, 5 and 9 buildings of more than 2 storeys.
E. Hydrant Coverage Changes
3.5.1 External hydrants coverage to multi-storey buildings
- If there are no internal hydrants, then external hydrants can provide coverage up to 4 levels above and 1 level below ground.
- If there are internal hydrants, then external hydrants can provide coverage up to 2 levels above and 1 level below ground.
3.5.2 Use of street hydrants
Street hydrants can be used in lieu of an on-site feed hydrant system if a maximum of two street hydrants are required to provide coverage to any building. A Location plan is now required to detail the location and performance of the street hydrants. It is typically located near the FIP or the main entry.
3.5.3 Simplified coverage measurement
Coverage is now measured as 40m from an attack hydrant and 70m from the appliance for feed hydrants. This is a simplification from the 10m water stream connected to a 30m hose that enters 1m into the room.
126.96.36.199(a)(i) 100m distance from a hydrant to a hardstand
The distance from a hardstand to an external attack hydrant located on a podium can be increased from 50m to 100m in a Class 9(c) healthcare building, and a building that is sprinkler protected throughout. If the extended distance to a hardstand is applied then the coverage distance reduces from 70m to 40m.
3.6.1 Internal coverage distance increased to 45m
If travel distances throughout the building are in compliance with the DTS provisions of the NCC then the internal coverage distance can be increased from 40m to 45m.
F. No Single Point of Failure
8.13.1(b) Redundant riser for buildings over 50m
Buildings over 50m high now require two independent risers located in separate stairs.
6.5 Redundancy in full-duty pump supply
The water supply serving each full-duty pumpset shall be configured with no single point of failure.
G. Block plan
The block plan must now also include the following;
11.5(g)(v) The length and size of underground PE pipework.
11.5(g)(viii) The location and ID number of each fire hydrant.
11.5(h)(vi) The water supply residual pressure.
H. Commissioning Test Changes
12.2 Hydrostatic pressure testing – Commissioning Test
- Appendix S gives procedures and acceptance criteria to pressure test feed hydrants, attack hydrants, and buildings with more than 50m height.
- Steel and PVC pipe is generally a 2 hour hold time and PE pipe is extended to a 5 hour hold.
- An allowable makeup rate formula is included to allow for air in the water being forced into solution.
I. New Pump, Tank and Hydrant Types
Pumps are spit into half-duty and full-duty pumps. Half-duty pumps require 5L/s per outlet and full-duty pumps require 10L/s per outlet in building greater than 50m height (Clause 2.2.6). Two pumps are required for buildings greater than 25m high (Clause 2.2.8). The intent is to remove the single point-of-failure that the fire appliance plus relay pump presented with two site-maintained full-duty pumps.
1.3.50 Fire water tanks
Tanks are split into several types. Break tanks, full-capacity tanks (4 hour supply), gravity break tank (in a high-rise to supply water at 700kPa without a pump), high-rise water tanks (minimum 36kL in a high-rise) and reduced capacity tanks (minimum of 24kL).
2.2.4 (c)Attack/Feed hydrants
An attack/feed hydrant is installed downstream of a booster, located externally, and within 20m of a hardstand. It requires an unassisted flow of 10L/s at 200kPa per outlet. The attack/feed hydrant is not a new concept but it is now included in the definitions as a new hydrant type.
J. Minor Changes
188.8.131.52(e) Hydrant ID plates
Hydrants require a 20mm hydrant ID plate connecting the hydrant ID to the block plan.
3.6.2 Internal hydrants not on the FFL they are protecting
Internal hydrants don’t have to be on the same FFL as the level they are protecting providing the hydrant is not more than 2 stairs above the FFL or not more than 1 landing below the FFL. This is for ascending stairs. See Figure H.7.2(B) for full details, this one is easier to see than read.
Enclosed rooftop plantrooms of more than 250m2 require coverage protection.
Marinas have a reduced coverage distance of 10m less than typical. Informative Appendix J makes recommendations on the minimum flow rate.
4.4 In-ground tanks
Below ground tanks can have a suction pipework with a maximum of 2.2m for 150MM pipe and 5m length for 100MM pipe. And a maximum vertical lift of 3m.
6.11.2(d) Diesel tank exhaust
Diesel engine exhaust must discharge outside the pump room to a safe location at least 2.7m above a path or road.
7.3.3 Hydrant accessibility
The hydrant must now be located more than 10m from any Electric Vehicle charging stations and more than 3m from the vent of a gas assembly.
8.7.2(b) Internal isolation valves
Internal isolation valves are to be installed inside a fire isolated stair (if applicable) and the valve handle within 2.4m of the ground level.
8.10 Flow test facility
A permanent flow test facility, with a pressure gauge, is required to safely drain test water if the building is more that 2 storeys high.
10.7.2 Threaded rod to support risers
Threaded rod cannot be used to support riser clamps and hangers.
Meet the Author
Dan Barwick is the Managing Director of HTC Group and a Chartered Mechanical Engineer (CPEng and RPEQ). He has 12 years of experience applying fluid dynamics theory to fire hydrant systems and industrial processing plants. He has knowledge of AS2419, AS1851, and the associated legislation. He is a member of the AHSCA, NFIA, and the BPEQ. Dan has presented technical content for AHSCA Qld and Vic chapters and has helped develop hydrant testing methodologies with Water Utilities in Queensland and Victoria.