Detecting fire protection (sprinkler) water flow

danw

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Oct 2004
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midwest, USA
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Query came in to add fire protection water flow alarm to an existing alarm system we manage at an out-of-state pharma in Tennessee. All I need is a contact closure, but determining what is needed to get that is the task at hand.

I am ignorant of the fire or building codes concerning
- tapping into a fire protection line to add a flow switch
- put a relay between what we suspect is a flow switch that connects a fire alarm direct to the local fire department

Nor do I know what actions can be taken to test a flow switch.

Do light industrial sprinkler systems have a flush valve that can be used to test a flow switch?

What bureaucratic actions are necessary when interrupting a fire protection line? Are permits other than construction permits required?

Any one with experience in this sort of affair?

Dan
 
I don't know the regulations or code in your jurisdiction but I can tell you what is installed in our plant.

The main fire protection piping has a check valve installed allowing flow in only one direction and a charge pump after this check valve. Once all the lines have been filled and purged of air the charge pump is turned on and charges the fire protection piping above the pressure of the city water service. There is a pressure switch monitoring the pressure in the charged line.
In our case the city water supply is at approximately 75 psi and we charge up the sprinkler header to 125 psi. The pressure switch is set at 100psi. If a sprinkler opens the pressure in the header soon drops below 100 psi and the system alarms.
 
Our building has a simple Viking flow switch - it appears to be a standard paddle type. It has a flushing/test line that dumps to our sump pump crock. The switch is wired to our centrally monitored alarm system.

You would be well advised to check with the local building inspector to determine local codes - they vary widely from one jurisdiction to the next.
 
From my experience you will have to do the following:



Deactivate the alarm temporarily. This will require a call to the Alarm Company and or fire department. You may also have to notify the plants insurance carrier. They may not allow the work without fire watch coordination especially during production times.

Deactivate the fire pump if one is present.

Drain the system if it is a wet system or depressurize if it is a dry system.

Install the flow switch.

Re pressurize the system. Then test. You would probably need a certified testing company do the test.

I doubt that you would be able to install a relay between the flow switch and the alarm system, both from a technical and a code standpoint.

NFPA (National Fire Protection Association) NFPA 25 covers inspection testing and maintenance of water based sprinkler systems.

NFPA 72 is the national fire alarm code.



Your best bet is to have the alarm company that installed the fire alarm system add a dry contact output to the alarm system that could tie into. Most new alarm systems can have spare outputs that can be programmed any way you like.
 
call the pros ...

if you'll check the sprinkler equipment in the mechanical room you'll undoubtedly find tags listing the company (example: Simplex-Grinnell) that regularly maintains and inspects your system ...

just call them up and tell them what you want ... any other course of action is probably going to set you up for trouble down the road ...
 
You need to check with your local fire inspector. In NC you cannot work on ANY part of your supession system without being licenced to do so. At my plant we paid $2500.00 to have a licenced contractor install an engine starter on our diesel fire pump. Our in house mechanic could have done it in 30 minutes, but it is against code.
 
How about strapping an ultrasonic flow meter to the pipe? We do this all the time for testing on our process piping. So, would this be against fire code? You aren't breaking the piping to install.
 
Thank you, Gentlemen, for a collection of knowledge on sprinkler systems.

The clamp-on ultrasonic came to mind immediately, but one still has to prove that it works, which requires some form of testing, which sounds like it might be a dump to a sump.

I can see that I'll be calling the firm that maintains the system to see about a contact from their panel.
Dan
 
If its a standard Potter or System Sensor flow switch then it will be a dual form C contact. One is typically connected to the FACP and the other is either not used or connected to an electric 120v bell outside the building. If the contacts are not used your all set.

Other option would be if you have an addresable fire alarm system the fire alarm contractor can add an addresable relay and program it to activate on waterflow.
 

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