We are designing a helicopter deck integrated fire fighting system (in-deck nozzles) according to NFPA-418 2016 for a offshore installation. The deck integrated nozzles are UL listed and approved by civil aviation authority-UK according to CAP-437 standard. We will have this system as self-contained type fitted with a fresh water pressure vessel with compressed air cylinders used as water supply source since there is no fire pumps on board to cater such high flow rates.
The question is about the discharge duration for such systems. Can these systems be designed for 5 minute discharge duration as against 10 minutes specified in section 220.127.116.11.
CAA-UK CAP-437 requires the DIFF system should bring the fire under control in less than 30 seconds and during various tests we have demonstrated that the system is capable of extinguishing fires in less than 30 seconds time.
In section 5.7.5 Water Supply 18.104.22.168 it states that the water supply for the foam system shall be from a source approved by the AHJ. In this section is there any possibility to reduce the water supply to cater for 5 minutes discharge?