With the legislation of AS1851 in NSW coming into force in 2025, the 5-yearly service of the fire hydrant system and sprinkler system will be mandatory for any building that has these systems installed. Civil Fire has already begun to quote these services. This article is intended to give a more detailed description of what the 5-yearly services involve, how they are completed and why it is needed. Click here for more general information about AS1851.
Hydrant Systems
A building’s fire hydrant system, featuring landing valves (like the one shown here) installed at regular intervals, enables firefighters to connect hoses directly to the hydrant system. The hydrant system is then required to deliver sufficient pressure and flow for firefighting on all levels.
Some hydrant systems will have a booster at the front of the property. This is where the fire brigade can connect their trucks to provide extra water flow and pressure into the hydrant system in order to achieve the amount of hose spray required to fight fire on every level. The taller the building, the more pressure and flow that is required to achieve adequate hose spray on the higher levels.
The purpose of the 5-yearly hydrant service is to replicate the conditions under which the fire brigade would use the hydrants to make sure there are no faults in the system. AS1851 tells us that at the 5-yearly service, we need to replace every hydrant landing valve, replace all of the check valves and replace all of the pressure gauges onsite. In order to replace these parts, the water needs to be drained from the hydrant system or frozen at the supply to avoid flooding the building. This new equipment then needs to be tested to make sure it can withstand the required pressure and flow that would be used by the fire brigade in the event of an actual fire. If your building has a booster, there are 2 x tests that are required to ensure the building can meet these requirements:
The booster flow test involves pushing water through the system to ensure there are no blockages or obstructions from the booster to the most remote hydrant (usually on the top floor of the building). It is essential for fire fighting operations that the water is able to flow freely through the whole building.Â
The hydrostatic test is designed to prove that the newly installed equipment and existing pipes can handle the pressure required to fight a fire. The test must be completed at 1.5x the working system pressure, so this can put stress on the system and reveal leaks or other issues. More information about hydrostatic testing here.Â
Civil Fire is currently using an ex-fire brigade appliance (fire truck) to undertake this testing. This appliance is able to connect to the booster and simulate the conditions required by the standard. Any faults or defects found during these test may then be re-quoted for rectification, and then the test will need to be completed again until the system is able to operate as required. For smaller buildings, a manual pump may be able to achieve the required pressure and flow to complete the 5-yearly testing, and this will be quoted accordingly.
Sprinkler Systems
A sprinkler system is designed to autonomously dispense water onto a fire without human intervention. Such systems play a pivotal role in curtailing the spread of smoke and flames, thereby mitigating the extent of damage incurred.
A sprinkler system is made up of sprinkler heads that are spaced along pipework throughout the building. The sprinkler heads all contain a glass bulb with a specific temperature rating. When the temperature reaches a certain point (depending on the rating of the bulb), the bulb will burst and activate that sprinkler head. You may have seen movies where one sprinkler head activates and every sprinkler in the building goes off. This is not how it happens in real life – only the activated heads will start spraying water to ensure that there is a maximum amount of water flow where it is needed.
Sprinkler heads are single use equipment, and once the flow of water has started, the only way to stop it is to isolate the water supply to the system. In the time it takes to isolate the water supply, a part of the building may be completely flooded. For this reason, the flow of water is not tested at the 5-yearly inspection at the sprinkler heads. Rather, the flow and pressure are tested at the main drain valve, and the serviceable parts are all replaced. This includes the sprinkler alarm valve, check valves, screw valves and pressure gauges. Replacing these parts extends the life span of the system without causing any damage to the building. A representative sample of sprinkler heads is required to be removed and tested at the 10 yearly (dry sprinkler systems) and 25 yearly inspections (wet sprinkler systems).
