By Koroush Keshavarz – Principal Fire Engineer
The new revision of the sprinkler standard has finally been adopted by the Building Code of Australia. The NCC 2019 Building Code of Australia Volume one issued in 1 May 2019 has referenced AS2118.1-2017 and AS2118.1-1999 has been phased out.
In this post I’ll overview what the new standard covers, what happens to Form 71, and a new method for calculating the water demands of sprinkler systems, but if you’d like to learn more or talk about your own sprinkler systems in more detail please contact me at firstname.lastname@example.org
The new revision of the sprinkler standard includes several newer technologies such as Early Suppression Fast Response (ESFR) sprinkler systems, and focuses more heavily on risk analysis approach, paying attention to water consumption and environmental impacts during sprinkler tests. Water supply arrangements for sprinkler systems have also been relaxed in the new revision.
The new standard no longer uses the terminology of ‘grades 1 to 3 water supplies’. The standard now only requires a single source of water supply to be provided to serve the sprinkler system. As such, the dual water supply previously required for grades 2 and 3 water supply is now obsolete. It recognises that while having a duplicate main increases the reliability of the system, it does not provide 100% redundancy for the system. This approach is in line with the international standards and guidelines such as Factory Mutual Datasheets requirements.
However, the standard makes it clear that the water supply (town main) should provide adequate flow for the simultaneous operation of sprinkler and hydrant systems. It has been noted that on some occasions designer or fire contractors are considering the water demand of the hydrant and sprinkler systems individually, whereas the standards’ intention is to add up sprinkler and hydrants water demands.
In Queensland, a Form 71 fire hydrant and sprinkler system commissioning test is used for the purposes of commissioning water-based fire safety installations, as required by the Queensland Development Code.
While this form is not intended to be used for all testing requirements for commissioning of sprinkler or hydrant systems, contractors are regularly using the form to demonstrate compliance of an existing hydrant and sprinkler system with the Australian standards. I believe the Queensland Building & Construction Commission (QBCC) must update Form 71 in order to clearly reference the combined sprinkler/hydrant water demand for buildings. This will guarantee that attending fire brigade units will have adequate water supply available in the event of a building fire.
AS2118.1-2017 also places heavier emphasis on water conservation. The standard now recommends that a recirculation tank is used to conserve and re-use water during periodic sprinkler control valve test, testing of pumps and system drain down.
With the new standard we also have a new method of calculating the water demands of sprinklers systems. The new method considers an assumed number of heads operating simultaneously in relation to the relevant hazard of the building space, rather than total number of sprinkler heads located within the ‘assumed area of operation’. This change provides increased transparency to the hydraulic calculation. For example, the new revision of the sprinkler standard requires the operation of 18 heads in an area which is categorised as ordinary hazard group 3, compared to AS2118.1-1999 which required all sprinkler heads located within an assumed area of operation (216 m2) to be included in the hydraulic calculation.
While these improvements to the standard are certainly very welcomed, I believe that AS2118.1-2017 requires further improvement to provide the same level of guidance and details that’s provided in the international standards such as NFPA 13.
If you’d like to discuss the new sprinkler standard in further detail and understand what it means to your current or future building project, please contact me at email@example.com