Can traditional fire sprinkler heads be used for Bushfire Spray Systems

1. Can traditional fire sprinkler heads be used for Bushfire Spray Systems Mark Potter Fire Safety Program Leader Country Fire Authority

2. Objectives What is a Bushfire? History of major bushfire losses Overview of USA study tour Overview of report findings Conclusion

3. What is a bushfire?

4. History of major bushfire losses

5. Study Tour Cedar fire area in southern California Globe and Tyco sprinkler companies NFPA Conference FM Global research facility Worcester Polytechnic Institute NFPA � Firewise National Institute of Standards and Technology (NIST) Literature review

6. Ramona House survived the 2003 Cedar fire. Sprinkler system supported by research report. Fed by an electric pump connected to a generator. Water supplied by an onsite tank.

7. Scripps Ranch House was unattended Sprinkler system was activated prior to evacuation Reticulated supply Sprinkler heads provided on one side of the house

8. Cedar fire impacting on Scripps Ranch

9. Lakeside Owner installed system Gravity fed from an elevated tank Predominantly plastic piping Activated prior to evacuation

10. Report findings It is possible to utilise traditional sprinkler heads in clearly defined circumstances, however the disadvantages will most likely outweigh the advantages.

11. Advantages Research found that the most effective method of delivering water onto glass when exposed to high levels of radiant heat is for the sprayers to provide the water to the tempered glass in a form that is like driving rain rather than streams flowing down the glass. Traditional fire sprinkler heads are fully enclosed and as such prevent the entry of foreign matter which may block the spray head.

12. Advantages Provided the traditional sprinkler head is installed correctly and will be exposed to radiant heat it can be considered automatic.

13. Disadvantages The system will only activate when the house is exposed to significant levels of radiant heat. I.e. the system will not operate when exposed to ember attack.

14. Disadvantages There is no provision for a manual override function. Under high wind conditions there is potential for overspray onto adjoining sprinkler heads to occur.

15. Design considerations The house must be exposed to at least 10 kW/m� for a minimum of 5 minutes to enable the sprinkler head to activate. Only those areas of the house that are exposed to in excess of 10 kW/m� can be provided with traditional sprinkler heads. The flow requirements for the system is to be the total of all sprinkler heads operating simultaneously.

16. Design considerations A thorough assessment of the bushfire risk must be conducted prior to the design of a bushfire spray system. The assessment must include as a minimum the location of all vegetation, the type of construction and define the expected bushfire attack mechanisms.

17. Alternative designs During the study tour and subsequent investigations the use of deluge valves was assessed. Two valves have been identified. The valves will activate after exposure to radiant heat with water being delivered via open sprinkler heads.

19. Advantages of deluge valves Allows a manual override to be included into the design. Eliminates the potential for overspray affecting the performance of other sprinkler heads. This system can be tested and flushed as required.

20. Conclusion Further research is required to: better define the flow rates required to limit the impact of radiant heat and flame contact. understand the performance of building elements when protected by a bushfire spray system. All bushfire spray systems must be designed and installed after consideration of the type of construction and the local vegetation.

21. Conclusion A bushfire spray system that utilises traditional sprinkler heads can be utilised however the disadvantages outweigh the advantages. A bushfire spray system that utilises a deluge valve can be considered as it provides flexibility and reliability.