waterflow detector in preaction sprinkler system

[morgan.z]

I recently run into a project which has a waterflow detector issue in preaction sprinkler system in multiple floors. For wet sprinkler system ,NPFA 13 has floor control assembly ,which has waterflow detector for each floor as in 8.17.4.2* Wet Pipe System . But this is only for wet system. It seems that no such approach for peaction or dry system. and my understanding is that ,for preaction or dry system, water will flows into all piping of all floors upon the fire detection triggering , so it can not detect which floor /or zone is on fire by water flow detector on the piping . it is impractical to install waterflow detector in each floor or zone , or ceiling/ rack if they are under one praction valve , only installing one waterflow detector like pressure -type on the mains is ok. Could please someone with experience advise. it will be very helpfull!

 

[UFT12]

See 6.8.2.3 & 4 (ed. 2016)

 

[cdafd]

How many floors are you talking about??

Regular enclosed building??

Or parking garage or similar?

It has to notify where the problem is,,, unless the sprinkler pops first,,, the smoke or heat detector will tell you the room or area it is.


Seems like something is missing.

 

[morgan.z]

Thanks a lot to UFT12 and cdafd!
I have 3 areas located in 3 floors installed with one preaction valve (riser), which already has a pressure switchs on water pipe of preaction valve( located on the header, to monitor the air leaking).
My question is : Is it possible to have water flow detector on water pipe on each floor area like floor assembly indicated in NFPA 13 8.17.4.2?
So it can tell on which floor , the sprinkkler water is coming out . The vane-type is not suitable for preaction system, is there other type of water flow detector which can be put in branches to do the job? i am not sure about this.

I know there is smoke (heat ) detectors in place which can tell which floor(area) is on fire.The smoke (heat ) detectors can tell which floor(area) is on fire. the pressure switches can tell if the water goes into the water pipe or not. but they dont tell if the water is coming out in the right floor(area).

 

[morgan.z]

I can do thing like floor assembly in NFPA 13 8.17.4.2 using pressure type water flow detector in each branch to each floor area in such preaction system, but i am not sure it can work.

 

[cdafd]

The answer to your question

I believe is no.

No matter what hopefully if a smoke detector goes off,,, someone goes and check.

Plus, depending on how your system is set up

1. Smoke detector activates, releases the pre action valve. All piping fills with water

This set up, no way to know which sprinkler might activate.

Or

2. Smoke detector activates ,,, pipe does not fill with water till fire sprinkler fuses.

 

[MGXFP]

Preaction systems can be subdivided per NFPA 13 but not with a floor control assembly. A check valve with a 3/32" diameter hole drilled in the clapper is used. This technique is generally used to increase the size of a preaction system and not trigger timed water delivery requirements.

If you have a double interlock preaction system, the addressable fire alarm system's smoke detectors will serve as an indicator of where the smoke/fire is located. Smoke detectors are required in these cases because a fire sprinkler being activated won't trigger a notification response in the alarm system.

 

[morgan.z]

Your answers are very helpfull , Thanks to MGXFP and CDAFD !
I am rest assured that the no additional waterflow is needed for each floor control assembly (if any) of preaction system,except the pressure switch on the preaction valve to monitor the air pressure .