What are combined sprinklers and hydrants systems as per Australian Standards; AS 2118 and 2419
Any fire protections system would be considered as combined fire sprinklers and hydrants system, if the source of water supply is shared between them and piping network for both the systems incorporates ring main.
If ring main is not incorporated and water supply meet the demand of both the systems simultaneously, fire hydrants can be designed as per 2419.1 and Sprinkler system shall be designed as per AS 2118.1
Sprinkler systems AS 2118.1
These Australian standard states that water supply can be shared with hydrants system but needs to comply with below provisions.
- The demand of both the systems can be met with water source with respect to flow and pressure.
- If the building to be protected is more than 2 storeys, AS 2118.6 comes into effect and all the requirements of AS 2118.6 needs to comply with respect to water supply requirements and infrastructure of piping.
- If the building to be protected is less than 2 storeys, AS 2118.1 says that
- System can have combined booster assemblies if flow is less than 120 L/s
- If flow is more than 120 L/s, separate boosters are required for each system and reticulation of each shall not be combined.
- A separate booster assemblies can be provided and, in that case, piping network after the pump outlet shall have separate lines to get boosted separately. This means, both the systems can share the water supply but cannot share the booster assemblies unless there is ring main in placed or the demand is more than 120 L/s
Fire Hydrants AS 2419.1
The requirements of this standard are fairly simple. According to this standard, any other fire protection system such as sprinkler system can share the water supply provided that the supply line shall meet the combined flow and pressure requirements. For example, if the sprinkler system needs 12.5L/S at residual pressure of 400kPa and hydrant system needs 20L/S at residual pressure of 1200kPa, the supply line shall have combined flow of 32.5L/S at minimum residual pressure 1200kPa to meet the demand requirements of both the systems simultaneously.
Combined AS 2118.6
States that any building more than 2 storey high should have combined fire protection system. It also says that it’s not compulsory, its choice.
Here are bit concerns from designer perspective. AS 2118.1 which is NCC referenced standards and each statement of AS 2118.1 is amount to code requirement sates that buildings more than 2 storey high shall be designed as per AS2118.6 which says that its choice.
Someone can read this in another way that AS 2118.1 leaves the designing of more than 2 storeys to AS 2118.6 and AS 2118.6 leaves this as choice to designer. So, it’s only the discretion of designer, whether to adopt requirements of 2118.6 or comply with AS 2118.1 and AS 2419.1 respectively.
Examples
-
4 storeys building which is less than 25 high.
Option 1. As per AS 2118.6, systems shall have combined piping network with ring main and combined booster assembly shall be provided as long as the flow demand is less than 120L/s
Option 2. As per AS 2118.6, it’s the choice. So, let’s design the system as per AS 2118.1 and 2419.1 respectively.
- Piping network for sprinkler system with separate booster
- Piping network for hydrant system with separate booster
- This option cannot share the booster connections
-
Building with rise in storey less than 2
Option 1. Design the system with
- Ring main
- Combined booster
- With minimum of 2 pumps if pressure is not met for any the system
Option 2. Design the system with
- Separate reticulation of each system
- Sperate booster assembly
- If the pump is required only for hydrant system, it will be only one pump as per AS 2419.1
Conclusion
If you need a fire system which would comply the Australian Standard requirements, feel free to visit our website; http://www.cybilconsults.com.au
