Deluge System with Regular Pendents Allowed?

11/25/2020

We have a large production facility where there is an isolated small room that is remote from the sprinkler riser room. This small room houses tools and other equipment which the owner sees as valuable property and does not want it to get wet unnecessarily, especially during trip testing when they test the deluge system.

The sprinkler system is an open-head deluge system, except for these few regular pendent sprinklers.

Are these pendent sprinklers acceptable to be installed on a deluge system?

I was under the impression that only open-head sprinklers could be used on a deluge system.

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3 Comments

Dan Wilder

11/25/2020 09:48:48 am

By definition, no and you are correct. If the owner is thinking that is a preventative measure to avoid water discharge into these rooms, sell him on a preaction system. The purpose of flowing all the sprinklers is to identify any that could be obstructed (not flowing). I'm betting these drops are likely plugged as there is no way to drain water/debris out of them.

Deluge Sprinkler System. A sprinkler system
employing open sprinklers or nozzles that are attached to a
piping system that is connected to a water supply through a
valve that is opened by the operation of a detection system
installed in the same areas as the sprinklers or the nozzles.
When this valve opens, water flows into the piping system
and discharges from all sprinklers or nozzles attached
thereto.

Glenn Berger

11/25/2020 10:15:40 am

Bad Idea! On the flip side, what will activate flow if the closed-head pendent sprinkler reaches its temperature rating. NOTHING!

Franck

11/25/2020 10:47:03 am

As indicated above, you should not mix deluge and closed sprinkler heads on the same system.
You could have 2 separate systems. One deluge for the main system and a small sprinkler system (preaction or wet), in the small room
(should be acceptable to the AHJ to have a small pipe connection to your remote water supply area and a valve + flowswitch to avoid the cost of an entire ACV for this small system).

In the current situation, you will have severe corrosion issues (in addition to the plugging by debris as indicated to Dan, that will accumulate to lower parts), especially since you indicated that the heads were pendent (if you trip your deluge system, the water will kept trapped at the pendent head location, and thus aggravating the corrosion issue for your entire piping system).

As indicated by Glenn, a fire in the high value room will activate the heads (if properly installed below the ceiling for heat accumulation), but maybe not the deluge system (if the detection system for deluge activation is not inside the room), and then you will have no water.
And if the detection system activating the deluge system is also extended to this small room, this means that a small fire within this room will activate the sprinkler in this room (ok, good news), but also the deluge system on the rest of the facility...
In all cases, not a desirable situation.

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