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I used to work in the old Douglas aircraft hangar at LAX; the ceiling was 37 feet to the lights and heaters and 40 feet to the sprinkler heads.

The sprinkler pipes were connected to a 10 inch water main piped under the floor from a perimeter square circle arrangement at ordinary city pressure.

The sprinklers were triggered by a sensor array on the ceiling and an emergency trip-handle in the fire closet where a 120 cubic foot Nitrogen bottle was piped to the unloading valve against a spring closure.

If triggered, the gas would open the valve and hold it open until the valve was manually reset.

The beauty of this system is that it required no electrical power to operate.

Back to the bottle as an explosive, over-pressured device: the amount of heat necessary to over-pressure air in a bottle would also be sufficient to burn through the piping long before the over-pressure condition ever occurred thereby releasing pressure and then this is a concern only if the sprinkler head fails to open and put out the fire (the source of heat).

I used to work in the old Douglas aircraft hangar at LAX; the ceiling was 37 feet to the lights and heaters and 40 feet to the sprinkler heads.

So getting the water to the pipes required about an atmosphere of pressure.

What was the function of the N2 bottle?