Fire Pump Bypass Code 1

[NickBammes]

thread184-325685

Can someone tell me where the code is that states why the bypass valves needs to be "normally open"?

LCREP (Specifier/Regulator)12 Jul 12 16:58
From NFPA 20, 2010 Fire Pump Handbook

In most cases, a pump that is connected to a public or private water supply should include a bypass. Only in rare cases, where the pressure available is so low that the water supply is of no value without the pump, should a fi re pump be installed without a bypass. When a pump is supplied by a suction tank, a bypass is not needed (see Figure A.6.3.1(b) because a suction tank will not provide suffi cient pressure to be of value without the fi re pump operating.[highlight #EF2929] The valves on the bypass are required to be normally open so that the attached water supply is available automatically.[/highlight] In this case, “normally open” refers to the valve being in the open position at all times. The bypass valves should be closed only for system maintenance. In some cases, the function of the pump bypass is mistakenly thought to be used only when the fire pump is out of service. This function is not the intent of the standard, because the water from the bypass must be available automatically if the pump fails to start.

 

[LittleInch]

Have you answered your own question?

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

 

[NickBammes]

No that doesn't answer my question. I copied a former forum post, but I am looking for the code that states that. To me, what he is saying is his words, not the code.

 

[cdafd]

My best answer from over the years,,,,

In case the pump fails,,,,, For Whatever reason,,

There is some water flowing through the system.

 

[NickBammes]

Yes, I understand the reason for it but I'm wondering if anyone can point me to the code that states, the OS&Y valve needs to be in the open position.

 

[LittleInch]

The code of common sense?

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

 

[UFT12]

See 4.16.4 of NFPA 20.

There is additional information in the commentary of the standard which is posted above. In there, it is clear that the intent of the committee is to have the bypass valves normally open.

 

[cdafd]

I think there are a few unsaid things in 20,,, That are kind of left up to the owner, designer, ahj, etc, to decide on how the pump is set up, and will function.

Does not mean the setup is right or wrong, just preference.

 

[LCREP]

See NFPA 20, 2013

See “bypass valve” in the section below. Does this help? The only time I have noted the valve closed is when they forgot to install the required check valve.

4.16.1 Supervised Open. Where provided, the suction valve, discharge valve, bypass valves, and isolation valves on the backflow prevention device or assembly shall be supervised open by one of the following methods:
(1) Central station, proprietary, or remote station signaling service
(2) Local signaling service that will cause the sounding of an audible signal at a constantly attended point
(3) Locking valves open
(4) Sealing of valves and approved weekly recorded inspection where valves are located within fenced enclosures under the control of the owner

Tom

 

[mk3223]

By putting the NFPA Code aside, the question is that, if the valve on the bypass line is no need to be open or isn't opened, what kind of the protection is from the fire water system?

Is it true that the system to be protected only as the protection equipment is activated and operated properly? The Code may not specify to open the bypass valve, or any specific valve, since the Owner is to determine what's the protection system and how to be operated.

 

[LCREP]

MK

The next time you do a fire pump test and or witness one do the following.

1.Open the pump test header and flow water say 500 gpm with the fire pump off, pump bypass open, record suction and discharge pressure gauges on the fire pump.
2. Do the same as 1 above, but close the fire pump bypass.

Which option provides the better water supply? Yea I know they both are terrible without the fire pump operating, but some water is better than none. Diesel pumps that do not start, or electric pumps with loss of power and no backup will have the same result.

Number 1 based on my experience.

Tom

 

[aaron johnson llc]

This section of NFPA 1 seems like it would only apply to valves on the backflow prevention device...which seems to make sense.