Are Two Valves Required in Fire Pump Bypass?

5/2/2024

Is it code-mandated to have two control valves in the fire pump bypass piping?

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7 Comments

John Sternitzke PE FPE CxA

5/2/2024 08:10:42 am

If you are talking about the city bypass or the street pressure bypass around the pump in the unlikelihood that the pump is impaired the valve is required on each side of the check below so that the check valve could be maintained.

Franck

5/2/2024 08:12:50 am

Yes
As indicated by John, because of the backflow/check valve

Glenn Berger

5/2/2024 08:16:35 am

The double valve is required to be there such that the check valve can be maintained without taking the entire system off-line.

Dan Wilder

5/2/2024 08:53:10 am

NFPA 20 doesn't have any specific requirements that I am aware of. Good practice would be to install a control valve on each side of the check valve for ITM to avoid impairing system(s) downstream of a pump.

4.16.4.1 - Bypass required if the city supply is of value to the sprinkler system (the bypass is not required when pulling from a low pressure source like a tank, or if the pressure isn't sufficient to overcome losses like pushing water up a hill).
A4.16.4 - The only location that shows a control valve on each side of the check, and having a check other than A4.22.1.3(a)&(b)
4.18.1-Bypass valves are required to be Normally Open.

There is no requirement for any valve as I read through things (open to being wrong on this?), they are there as common sense or per appendix sections.
To avoid recirculation, a check valve needs to be installed.

4.27.6.5 comes close with "Indicating valves shall be installed in such places as needed to make the pump, check valve, and miscellaneous fittings accessible for repair." but this is for a Pressure Maintenance Pump

Jessica Lutz

5/2/2024 03:54:19 pm

The most common arrangement is a gvd swing check with gvd butterfly valves on both sides (normally closed).

Don't forget to put quantities of tampers and flows on your layouts folks. 👍✔

Jessica Lutz

5/2/2024 03:59:03 pm

...and by "normally closed", I mean "normally open."

Jack G

5/2/2024 04:34:27 pm

Many years ago, 1950-1960, the norm was to mimic plumbing rules and codes.
If there was a meter pit for the water meter due to water company regs, the pit had a bypass with a single valve around it, normally closed. It would be opened to work on the meter etc.
same with fire pumps- going back to as I can remember 1948, pump had a bypass with one shut valve. Opened when working on or replacing the pump. The meter with check would be installed inside the building.
Heck, high rises in Philadelphia, Jersey, Delaware, would be installed with no pressure maintenance pump( jockey) due to the elevation head, and no bypass because city water protect the building.
Built with careful review of fires by nfpa, and building codes, things change mostly for the better. Not always, but mainly.
Of course it makes Fire Protection costs go up.
I can remember making deals on warehouses for 70 bucks a head. Not any more—- now sprinklers ca cost almost that. Go with the flow and help prevent damages to life and property from fires.
Opinion.

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Are Two Valves Required in Fire Pump Bypass?

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