Sprinkler System Plumbing

This Christmas Tree tops the fire sprinkler system in the Wentworth by the Sea hotel in New Castle NH:

Fire sprinkler system plumbing
Fire sprinkler system plumbing

The long pipe leading around the corner to the left-front riser drains the test valve. The honkin’ big supply pipe stands to the rear of the regulators and valves. You can’t quite see it from here, but those water pressure gauges showed about 180 psi.

The bathroom fixtures had the usual pressure and instant hot water, so there’s complex plumbing inside the walls, too.

Some equipment, you hope just never get used…

6 thoughts on “Sprinkler System Plumbing

  1. The pressure has to be enough to overcome the ‘head’ (approximately half a pound per square inch per foot of head) and leave enough to operate the sprinklers at the highest level.

    1. If I’d been thinking, I’d have taken a picture of the pressure gauges on each floor. There should be 20 or 30 psi difference from top to bottom, so, with 180 psi on the top floor, it’d be well over 200 in the basement!

      There’s no such thing as a slow leak at those pressures…

  2. I could not readily find the pictures I took a few years ago of several I saw that were considerably more complicated. It really looks like a Rube Goldberg device, but I could never find the bowling ball section. I’m sure that it all has a purpose, but upon first glance and knowing what it does, it seems rather unnecessarily complicated. Love to see a block diagram, it might explain a few things.

    1. I think the long drain line provides a way to test the pressure-drop alarm switch, but beyond that it’s a mystery.

      We’re obviously the kind of people who routinely take the stairs just so we can find them in an emergency…

  3. That is a relatively simple installation, imagine a system on a passenger (cruise) ship where the water, after the the pressure drop switch activates, comes from a sea water pump to supplying the system. That pump will be fed by emergency electrical power and, arrangements will be required to flush the system of seawater after use, or test, to prevent corrosion. Another twist is when the water lines are subject to freezing temperatures and the lines are charged with nitrogen.

    1. when the water lines are subject to freezing temperatures and the lines are charged with nitrogen

      That sounds like it’d be a delicate operation on a sprinkler system, but it’d certainly make sense in a large structure where the alternative is having all those steel pipes crack!

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