[Sprinklerforum] Re: Distance to fire pump suction

John Denhardt Sat, 07 Oct 2023 08:29:08 -0700

NFPA 20 - 2023 edition is below.

Hmm. I see the issue. This will be added to AFSA NFPA 20 - 2028 list to clarify or address.

4.29.3 Devices in Suction Piping.

Where located in the suction pipe of the pump, check valves and backflow prevention devices or assemblies shall be located a minimum of 10 pipe diameters from the pump suction flange.

John August Denhardt, P.E.

Vice-President Engineering and Technical Services

American Fire Sprinkler Association

301-343-1457

On Oct 7, 2023, at 11:19, John Denhardt <[email protected]> wrote:

I have always used the suction flange size of the fire pump. The suction pipe size and backflow preventer size can vary. I will look at NFPA 20 when I have a chance and see if I can find a reference for you.

Thanks,
John

John August Denhardt, PE
Vice President, Engineering and Technical Services
American Fire Sprinkler Association
m: p: 301-343-1457
214-349-5965 ext 121
w: firesprinkler.org

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On Sat, Oct 7, 2023 at 10:52 AM Fpdcdesign <[email protected]> wrote:
Fire pump is a 250 gpm at 60 psi

Todd G Williams, PE
Fire Protection Design/Consulting
Stonington, CT
860-535-2080 (ofc)
860-554-7054 (fax)
860-608-4559 (cell)

On Oct 7, 2023 at 10:48 AM, <Tstone52> wrote:

Todd,

According to NFPA 20, 2013 ed., 4.26, Table 4.26 shows 4” minimum suction.

2022 ED. Is the same.

Regards,
G. Tim Stone

G. Tim Stone Consulting, LLC
NICET Level III Engineering Technician
Fire Protection Sprinkler Design
and Consulting Services

   117 Old Stage Rd. - Essex Jct., VT. 05452
                 CELL: (802) 373-0638
             [email protected]

From: Fpdcdesign <[email protected]>
Sent: Saturday, October 7, 2023 10:16 AM
To: Discussion list on issues relating to automatic fire sprinklers <[email protected]>
Subject: [Sprinklerforum] Distance to fire pump suction

I have a system with a 6” backflow preventer, which reduces to 4” immediately after. There is approximately 48” of 4” pipe to the suction flange on a 4 x 3 pump. All elbows are turning correctly. Is this sufficient? Does the 10x rule apply to the size of the backflow preventer or the fitting directly attaching to the pump?

Todd G Williams, PE
Fire Protection Design/Consulting
Stonington, CT
860-535-2080 (ofc)
860-554-7054 (fax)
860-608-4559 (cell)
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[Sprinklerforum] Re: Distance to fire pump suction

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