Provision of Globe Valves In Fire Water System

[Shahpar]

Hi,

I am working on one project in which process and safety Department have used Globe Valve in Fire Water System for PCV bypass on recycle line from the pump discharge header back to the suction source of the pumps. Refer to NFPA section 6.1.1: All valves controlling connections to water supplies and to supply pipes to water-based fire protection systems shall be listed indicating valves. We could not find any Globe Valve available in market with UL/FM approved. Also I could not find any FM approval procedure for Globe Valve.

Can anyone provide expert opinion on this issue, whether we can use Globe Valves in FW water system as this is usually considered as non indicating type valves. I have seen some provision of globe valve in NFPA-20 on drains Refer NFPA-20 Fig: A.4.31(a).

 

[bimr]

The Cla-Val Pressure Relief Valves are designed specifically for fire protection pumping systems and are available in a variety of configurations and end connections. These are automatic glove valves.

Cla-Val

 

[Shahpar]

Thanks for your response. However, We require manual globe valve on the bypass of PCV with UL listed and FM approved.

 

[LittleInch]

Which NFPA code do you refer to above - there are lot of them!

Generally NFPA systems treat pumps appallingly and have no return line or min flow bypass in many systems I've seen. I've seen large fire water pumps regularly (weekly) fired up and run for 15 minutes at dead head to prove the system. Heaven only knows what this does to the pump, but NFPA doesn't seem to care. If your process and safety dept are looking at this like any other process system, they need to think again. NFPA work in an alternate universe and vendors work to a very very fixed design. You can ask for all sorts of changes and additions to make it like the way you design everything else and they just ignore you, at least in my experience...

I can only think they work on the basis that such valves can be set badly, can fail or can allow more water to pass than it should and just normally don't use flow or pressure regulating valves in their systems.

There is a specialist NFPA forum in the engineering codes heading. Try searching there or starting a new post on this subject there.

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[Shahpar]

Thanks LittleInch,

I forgot to mention, the reference Code is NFPA-24 section 6.1.1.

This recycling line is requirement of Client Safety Standard which cannot be avoided. This standard statement are as under:

Water pressure shall be controlled by recycling fire water from the pump discharge header back to the suction source of the pumps. The fire water pressure control system shall consist of a dedicated pressure transmitter, a pressure controller with adjustable set point, and at least two pressure control valves installed on the recycle manifold.
The pressure control valve system shall be sized to recycle a minimum flow of one half the design capacity of the smallest jockey pump and shall be designed to fail closed. The maximum recycle flow of the system shall be two times the sum of the design flows of one jockey pump plus the largest single fire water pump.

Therefore, In this case I dont think there is some way if we think again. Thanks for your guidance, I will definitely start new post on this subject on NFPA forum as well with some more details.

Regards.

 

[LittleInch]

Good luck.

It sounds to me like a conflict between client spec and NFPA. If you want 100% compliance with NFPA you can't have that fancy looking pressure control system (at least AFAIK). Find out the details then it's up to the client what he want to do.

Fire systems really need to be very simple and essentially bullet proof. When it all needs to work in the dark, with no power or light and something on fire the last thing you want is your pressure control system throwing a hissy fit and opening up fully.... Hence you would need to make your pressure control system something like SIL3 standard - that's a lot of cash for something that isn't needed.

LI

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.