Reducing Water Consumption of Fire Protection System
Advisory Note
December, 2009
Due to prolonged drought in many parts of Australia there is a heightened community consciousness in relation to unnecessary water consumption. While water based fire protection systems are generally designed to be operated only when there is a fire, they need to be regularly inspected and tested to help ensure they will operate when needed. The inspection and testing regimes confirm both operation and performance of the system and although necessary, such inspection and testing generally consumes potable water.
To help address community concerns & reduce water consumption due to maintenance of Fire Protection systems the Victorian Plumbing Industry Commission has led a project as part of a Victorian Government initiative examining ways to minimise water use during maintenance and testing of fire sprinkler systems. The project has taken over 2 years to complete and culminated in a guideline describing a number of initiatives to minimise water consumption of operational fire sprinkler systems. The guide is available for free download from the plumbing industry commission website (http://www.pic.vic.gov.au).
Although the scope of the guide is limited to fire sprinkler systems, most of the initiatives can be adapted to other water based fire protection systems, such as fire hydrant & fire hose reel systems. A total of seven initiatives have been identified as follows
1. Pressure Setting Adjustment: This initiative is applicable to systems which have booster pumps to achieve the required system performance. The PIC research project found that many fire pump pressure relief valves aren't set properly, operating too early and unnecessarily discharging water during regular weekly/ monthly testing. There are four main areas of focus for this initiative
- Optimising the pressure relief valve setting.
- Increasing pressure relief valve setting in diesel pump raw water cooling lines to minimise discharge to drain.
- Adjusting pump start pressures in multi pump installations so that the 2 pumps do not start together.
- Provision of a pressure schedule
2. Monthly Testing: The revision of the AS1851 fire system maintenance series of standards introduced an option to adopt monthly testing in lieu of weekly as traditionally required. This has the obvious water saving advantage of conducting only 12 monthly tests in lieu of 52 weekly tests saving around 75% of the water used in this component of the maintenance regime.
3. Pressure Reduction: Similar to pressure setting adjustment the objective of this initiative is aimed at minimising operation of pressure relief valves by reducing the operating pressure of the pump where the pump duty significantly exceeds the system requirement.
4. Recirculation: This initiative comprises installation of a recirculation system to capture water discharged during a test and re-circulate it back into the system. This initiative is applicable to pump boosted systems which are suitable for pressure setting adjustment or pressure reduction initiatives.
5. Capture and Re-use: Water from testing activities is captured and re-used for other purposes such as:
- Toilets and sanitary fittings
- Urban irrigation
- Donated to council for street cleaning
6. Improved Drain-down Zoning: Alterations to sprinkler systems normally require the water in the system drained down to permit the changes to occur. For buildings that undergo regular changes this can result in a significant quantity of water use for just drain down and re-fill of the system. By installing subsidiary stop valves and/or check valves to zone the system, coupled with local drain valves in each zone. This avoids the need to drain the entire system just to undertake work in one part of the building.
7. Drain-down Management: This is a non-physical initiative using management principles to plan, monitor & review system modifications to reduce the need for system drain-down. Strategies include
- Use of impairment notice system to justify need to drain the system.
- Consideration of alternatives to drain down.
- Programming and consolidation of works to minimise frequency of drain-downs.
The suitability of each of these initiatives will vary from site to site and from system to system, however the first three initiatives are likely to be the most cost effective to implement for a majority of buildings.
For further information please contact:
Geoff Flower
Engineering Services Manager
Walker Fire Protection
on 03 9279 7100 or engineering@walkerfire.com.au
While every effort has been made to ensure the accuracy of the information in this publication A. G. Coombs assumes no responsibility for errors or omissions or for any consequences of reliance on this publication.