Fire Pump Best Suited with Aboveground Tank?

3/13/2019

A fire sprinkler system for a single building requires a tank for water storage as there is only a well at this project's remote site. We're considering using a diesel pump with a pump house adjacent to an aboveground water storage tank.

What type of fire pump would you recommend for this scenario?

The building is only Ordinary Hazard Group 1, so I'm expecting an approximate pump size of 500 gpm, 75 psi, 50 HP. There will not be much suction pressure since the water storage tank will not be pressurized.

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11 Comments

3/13/2019 10:08:15 am

Look at this website: www.talcofire.com I have used these for a project like the one you described.

Rusty Scott

3/13/2019 10:24:28 am

Had a somewhat relatable project but with a 100 psi, 1,000 gpm horizontal split case fire pump with an elevated tank. Due to structural cost reasons we switched to building a custom concrete type vault under the building and sump and used a vertical turbine fire pump. I would say talk to a pump rep I use Patterson and Peerless alot. Both guys are very knowledgeable and deal with a large variety of pump projects beyond just fire related. My pump rep's often inform me that when we go below 750 gpm they like to use a vertical in-line pump, but that's also with a city connection and not a gravity tank. Hopefully this is helpful.

Kelly

3/13/2019 10:29:33 am

You should probably look into the environmental requirements of the site and make sure diesel will not require extra permits or be flat out prohibited in the area. I have run into this in a couple of states - just make sure you coordinate with the civil or environmental engineer on the project.

John P Malescio

3/13/2019 10:40:14 am

I had a similar project, although it was much larger. I would speak to your fire pump representatives to get a starting point. I had a 150k gallon above ground tank and I used a horizontal split case pump. The NPSH was well above what I needed for the pump even when the tank was 90% empty.

James

3/13/2019 10:51:15 am

If you have the room for it, a horizontal split case lasts long, is very efficient and easy to service.

If space is a constraint, you can go with a vertical inline.

Here is a pump handbook that you can use to help narrow down your selection:

http://noteswww.grundfos.com/web/homeind.nsf/Grafikopslag/handbookPDF/$file/Pump_handbook_industry.pdf

PETE

3/13/2019 11:33:33 am

1) I would make sure that your suction tank and pump don't need to also supply the fire flow demand. I've designed suction tanks that are 450,000 gallons. The supply has to provide the greater of the fire flow and the overhead demand, not both per NFPA 1/ IFC. This is an AHJ question. He/she may not require private hydrants for fire flow on the site.

2) What kind of well pump is filling the tank? Will it need a strainer? You will have to design the fill line with a float valve or sensor and solenoid valve. To keep the tank size down, you may have to do a fill-time calculation in order to get your fire flow duration.

3) What is the reliability of the power source (electrical)? Has the power purveyor experienced shut-downs longer than 4 hours in the past yr? Have they had power grid failures recently? Does the service point connection come from off site using overhead conductors? IF yes to any above, I would go with a diesel.
Otherwise electric is fine, provided that all of the provisions of NFPA 70 are followed in the service wiring.

4) Horizontal split-case and vertical inline are equally viable, but the inline is sometimes preferred for small pump rooms.

WES

3/13/2019 12:49:23 pm

Pete,

These are each excellent points. I agree wholeheartedly on use of electrical when possible and the horizontal split-case (very common for us) and vertical inline when space is an issue.

Could you point me to a reference in the International Fire Code that addresses water storage for EITHER sprinkler system or fire flow, but not both (your point #1 above)?

WES

3/13/2019 12:53:02 pm

I see now that the 2015 IFC B105.3 clarified that it is the greater of the automatic sprinkler system, plus hose, or fire flow. Thank you Pete!

Mike

3/13/2019 06:50:04 pm

Diesels in some states need to be Tier 4 emissions. The exhaust system for these is as costly as the pump and driver. Very expensive But sometimes necessary because of lack of electrical supply.

Also need to keep in mind weekly testing gradually depleting fuel supply which will eventually lead to costs to maintain an 8 hour fuel reserve.

Danny

3/13/2019 07:40:24 pm

I think it would be wise for anon to hire an FPE to do a complete evaluation.

Joe Meyer

3/14/2019 06:35:51 am

Danny,

Thanks for your input! There are questions (that we've all undoubtedly have heard) that show someone's complete lack of understanding for the situation they're responsible for. There's also questions that just seek to gain additional knowledge from peoples' opinions and perspectives outside his/her own.

I happen to know who submitted this question and I can assure you that this question is the latter scenario.

Besides, if the question was not asked we wouldn't have had the opportunity to learn from the very helpful insight that Pete, Mike, Rusty, James, John & Kelly all provided which is exactly the intent for this site. I've learned several things just from this discussion.

Thanks Danny & all the best.

Joe

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