Domestic Pump and Fire Pump Connected to Combined Water Service

[CFreels]

Thanks to whoever reads this and takes the time to answer.

I've got a project with a fire pump and a domestic pump both connected to the same water supply distribution pipe that feeds several buildings on one site. The pumps are in parallel and water will only flow through the fire pump if a fire system demand occurs that the domestic pump can't keep up with, which basically means a fire hydrant has been opened.

The plumbing contractor is refusing to perform the work in the pump house containing these pumps because the fire pump is not specifically rated for domestic water use and therefore the water passing through it becomes non-potable in his opinion. The plumbing contractor has now convinced the GC that we've designed something that is not allowed by code, even though this is a common system and is even referenced in NFPA codes. This particular project is under the International Plumbing Code.

I've never had this angle come up before. Normally, I'm having to answer why a domestic booster can be on a fire system, and not the other way around. Has anyone had any experiences like this or thoughts on what the counter argument should be? Is there even such a thing as an NSF 61 rated fire pump?

If you think that the contractor is right, that's fine to let me know also. But then please tell me how this type of system ever meets code. A duplicate post for this will be added to the IBC codes forum also.

Thank for your help!

 

[cdafd]

Is this in the USA?

IS the system only feeding fire hydrants??? and nothing else??

 

[CFreels]

System feeds a combined domestic/fire service throughout a garden style apartment property. Each building takes domestic water and sprinkler water from the main and fire hydrants are also attached to it.

Basically, its the same as a public water main system, only its a private system on private property.

 

[TravisMack]

We've run into this on projects. We have one that is a slightly different scenario. There is a domestic pump for the site. The site fire loop feeds domestic lines, hydrants and sprinklers. Every sprinkler system has a backflow on the sprinklers so not a potability issue. The consulting design team is wishing to only use the domestic pump. The fire pump will basically never turn on as the domestic pump is sized for the entire domestic load plus site fire flow demand. Therefore the developer doesn't want to spend the $$ on the fire pump. If this domestic pump were at the city pump station, there would be no issue. It is no different than just a municipal main. But, because fire sprinklers come off, the fire dept wants a fire pump that will only turn on for ITM.

Back to the original question, we've seen the scenario you present multiple times with no issue from anyone.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, a Ferguson Enterprise

http://www.mfpdesign.com

 

[CFreels]

@TravisMack - We've probably done about a dozen of these systems over the years with no problems until recently. This year I've been drug into conversations with the various sub contractors all fighting over who must / can install which pipe in the pump house. Its all getting very frustrating, particularly since it should be the GC sorting out the arguments between subcontractors.

 

[TravisMack]

@cfreels:

That can be challenging. It would seem the labor disputes of who can or can not would be handled by the GC or, if in union territory, by the BA's of the respective trades.

Hopefully you get a Christmas miracle and have it resolved by the end of the year.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, a Ferguson Enterprise

http://www.mfpdesign.com

 

[FacEngrPE]

Fire pumps and controllers must be type listed for fire pump application. If your AHJ / state regulations require all components of a domestic water system to be NSF 61, you will find that is not one of NFPA's requirements for a fire pump; However there are some fire pump manufacturers that certify some of their pumps as NSF 61.

This link will find some NSF 61 type certified fire pumps.

https://duckduckgo.com/?t=ffab&q=fire+pump+nsf+61&ia=web

The question of whether water passing through a non NSF 61 pump becomes non potable sounds to me like an AHJ question. Once you know what the AHJ's position is you will know how to approach your plumber.

 

[CFreels]

@FacEngrPE - Thanks for the advice. I'm planning to discuss this with the AHJ after the holidays. This was all included on the original permit, so I don't think that they would have any issues now.