Fire pump potable water requirements

[Jeng84]

The following question pertains to a project in the US, i.e it is following all applicable US codes; IBC, IFC, NFPA 13, 20 etc.

The project is an industrial type campus style project. It has a fire loop that feeds the sprinklers, and a dedicated fire water tank with a fire pump (tank is existing and meets code required sprinkler demand). The hydrants are fed off the domestic water line. The domestic water line feeds all domestic water sources on site, the hydrants and also provides make-up water to the fire water tank. Recently it was discovered that the project does not meet the water supply requirements for the fire flow.

As the tank is already existing, it is proposed to provide a booster pump station where the water enter the site, the booster pump will increase the make-up rate from the domestic water system to the tank so it refills faster. The pumps will only be energized when the fire pump is running and the water level in the tank is dropping.

Since the booster pump station is delivering the water to the fire tank through the existing domestic water piping system - does the pump need to meet both fire pump requirements and potable water/NSF 61 requirements?

 

[Heaviside1925]

that the project does not meet the water supply requirements for the fire flow

Which fire flow are you referring to?
If the booster pump is part of the fire water system, then there should be the required back flow prevention methods taken, so the booster would no longer be considered part of the potable system.
If the booster pump is part of the potable water system for the entire campus, then it would need to meet both domestic demand and fire flow demand but would not be part of the fire water system if it's considered dual use distribution.

If you could share a flow diagram of what you are proposing, it would assist in answering your questions.

 

[Jeng84]

Appreciate the response, and sorry for the confusion, let me see if I can clarify (unfortunately don't have flow diagram:

It does not meet the fire flow requirements per Appendix B of the IFC, this jurisdiction requires 4,000 gpm for 4hrs.

The booster pump is not required in order to meet domestic demand - the booster ONLY energizes when the fire pumps kick in AND tank levels decrease, but because it is boosting a potable water main (to refill the tank) I'm being told it needs to meet potable requirements. You make a good point though, as it needs back flow prevention or an air gap to be considered a separate system, I think it is considered one system.

So I think you helped me answer the question of it needs to meet potable requirements, but can it then be argued that it is not a fire pump hence don't need to meet fire pump requirements based on NFPA 20?:

A.4.7.1 This subsection does not preclude the use of pumps in
public and private water supplies that provide water for domes‐
tic, process, and ƒre protection purposes. Such pumps are not
ƒre pumps and are not expected to meet all the requirements
of this standard. Such pumps are permitted for ƒre protection
if they are considered reliable by the analysis mandated in
Section 4.6. Evaluating the reliability should include at least the
levels of supervision and rapid response to problems as are typi‐
cal in municipal water systems.
If a private development (campus) needs a ƒre protection
pump, this is typically accomplished by installing a dedicated
ƒre pump (in accordance with this standard) in parallel with a
domestic pump or as part of a dedicated ƒre branch/loop off a
water supply

 

[Heaviside1925]

If the booster pump is supplying the domestic water system, which it sounds like it is, then

Such pumps are permitted for fire protection if they are considered reliable by the analysis mandated in Section 4.6.

It may only kick on when fire demand is present but is not part of the fire protection system.
That said, the AHJ or Underwriter may argue that a parallel system is required:

If a private development (campus) needs a fire protection
pump, this is typically accomplished by installing a dedicated
fire pump (in accordance with this standard) in parallel with a
domestic pump or as part of a dedicated ƒre branch/loop off a
water supply

If this is the case, your arguments would not be valid.