Combined Domestic/Fire Pump for NFPA 13R?

9/9/2021

I'm reviewing a apartment building that meets the requirements for an NFPA 13R system.

My questions: A pump is going to be required for this project and they are proposing to use a booster pump on the incoming waterline at the property line to reach the required pressure for domestic and fire demands.

Is a combined domestic/fire pump like this allowed?

It would be a private pump.

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9 Comments

Alex

9/9/2021 07:09:48 am

HI Anonymous,

NFPA 20 (2019) 4.7.1 states that “fire pumps shall be dedicated to and listed for fire protection service”. If you stop there, then you would simply install two pumps (one domestic, one fire) in parallel.

Although, reading further leads you to section A.4.7.1, which states that the above code section is not to “preclude the use of pumps in public and private water supplies that provide water for domestic, process, and fire protection purposes”. It states that combined pumps are not called fire pumps and are not required to meet all requirements of NFPA 20. The combined pump is permitted for fire protection only if “they are considered reliable by the analysis mandated in Section 4.6”.

In the end, since you won’t be providing a dedicated pump, I would reach out to the AHJ early on to discuss your design approach and make sure you don’t have any issues when it comes to receiving your permit.

Best of luck with your design!
Alex

Paul Pinigis

9/9/2021 08:13:10 am

Alex beat me to it. A single pump is permitted (as Alex explained in detail) and often has a reliability advantage because when there is a problem, it is immediately detected by those using the domestic water in the building. Therefore, it is more likely to be fixed when there is a problem.

Peter

9/9/2021 08:28:33 am

If the pump isn't dedicated to fire protection is it still inspected, tested, and maintained according to NFPA 25? The reliability of the pump is one thing in terms of "I know the pump turns on because my toilet still flushes", but NFPA 25 has prescriptive requirements for measuring flow and pressure (amongst other requirements) and comparing those readings against system demand and nameplate/original curve data. Not performing those inspection and test requirements wouldn't identify that the pump has degraded performance and now potentially does not meet system demand. In my experience with the hundreds of pumps we provide ITM on, the pump almost always "turns on and moves some water" but then fails to meet the requirements prescribed in NFPA 25 for performance.

Additionally, a number of states have different licenses for plumbing and fire protection contractors. Since the pump isn't dedicated to fire protection, would it be the plumber responsible for ITM or the fire protection contractor? Not having it dedicated would appear to be a long term nightmare.

Peter

9/9/2021 08:17:10 am

To piggyback off of Alex's comment,

NFPA 13R, 2016 9.3 The Water supply source shall be one of the following:

(1) A connection to a reliable waterworks system with or without a pump, as required.
(2) An elevated tank
(3) A pressure tank installed in accordance with NFPA 13 and NFPA 22
(4) A stored water source with an automatically operated fire pump

NFPA 13R, 2016 9.4 "Where a fire pump is installed, the fire pump shall be installed in accordance with NFPA 20."

To add some more color the A.9.3(1) states that "Private pumps taking suction from the waterworks system need to comply with NFPA 20, even if they supply both fire protection and domestic water uses, unless they comply with the same waterworks
industry standards for reliability and redundancy as the pumps owned by a waterworks utility"

The NFPA 13R handbook then also states "Subsection 4.7.1 of NFPA 20 mandates that fire pumps be dedicated to fire protection service. Therefore, it is unacceptable to supply domestic systems with a fire pump installed in accordance
with NFPA 20."

Since a combined pump wouldn't be considered a fire pump, it would also not have any of the ITM requirements for pumps in NFPA 25. I think you'd have a very difficult time convincing an AHJ that you want to put in a combined pump rather than a dedicated fire pump especially since NFPA 13R requires it.

Jesse

9/9/2021 08:35:07 am

Alex beat me as well.

I would highly recommend consulting your AHJ before doing anything though.

Bill

9/9/2021 09:08:07 am

As an AHJ my first question would be, is the pump required to meet the demand of the sprinkler system, or is it required to meet the demand of the domestic water? If it is needed to meet the demand of the sprinkler system, then I think NFPA 20 would apply.

John G

9/9/2021 11:19:27 am

They make domestic water automatic shutoff valves when the fire system activates.
I don’t know why, unless you are pumping from a tank, that you would want a pump on your domestic. Too high a pressure without pressure reducing valve would blow out your plumbing fixtures ( so boost pressure then reduce pressure ? Crazy) and a 4 head design can be accomplished with relalitively small piping with 40 psi which is average almost everywhere.
A fire pump……. I mean for 13d, or r , off domestic…..yikes. Waste of money.

Pete

9/10/2021 12:44:35 pm

Maybe check the Econo RFP System residential fire protection pump? It's designed for 13D systems more than 13R, but it's a specific residential fire pump.

Pete

9/10/2021 12:50:54 pm

Disregard this. 13R 9.4 directs fire pumps to be in accordance with NFPA 20. 13D does not have as strict requirements.

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Combined Domestic/Fire Pump for NFPA 13R?

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