Include Hose Allowance in Fire Pump Size?

5/19/2022

We have a two-zone fire sprinkler system, one is wet, the other is dry-pipe. There are no inside hose valves, just a small NFPA 13 building.

Does the fire pump size need to accommodate hose allowances?

The sprinkler calculations have no inside hose allowance. We would typically apply the hose allowance at the city tap, which would be upstream of the fire pump.

Thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

6 Comments

Alex

5/19/2022 06:35:55 am

Hi,

The fire pump should be sized according to the system demand. Therefore, if you do not have any inside hose valves, you would not need to add additional flow to the system demand.

And correct, NFPA 13 (2019) 27.3 states that "outside hose shall be added to the sprinkler and inside hose requirement at the connection to the city water main or a yard hydrant, whichever is closer to the system riser". This will be prior to your fire pump. However, it should still be added within your hydraulic calculations to ensure the city can handle the additional flow.

Thanks,
Alex

Glenn Berger

5/19/2022 08:06:49 am

Size the fire pump for the system demand, but be cognizant of the available flow to the fire pump with the required flow for the hose streams.

Sanjeev Gupta

5/19/2022 08:47:49 am

I understand fire hose is the basic safety equipment similar to portable fire extinguisher. If it is not a high rise building or containing any high hazard items, then sprinkler system may not required. Anyway, I its decided to put sprinkler system then also manual hose system shall be required as backup if by case sprinkler valve/pump malfunction. If there is nearby municipal external hydrant and not a multiple floor building then it can meet the requirement.

Jesse

5/19/2022 10:17:19 am

No. In your case, the hose allowance is pulling volume off of the system before the intake flange of the pump. Depending on your design software, you should be able to assign a hose allowance ot your water supply node to account for it.

Casey Milhorn

5/20/2022 11:16:16 am

As almost everyone has confirmed, no hose allowance at the pump or after the pump. The only exception for us, is when we have an existing fire pump and fire pump test to use for a remodel, retrofit, or addition. I prefer to use the actual pump test as the flow test. It's more accurate than trying to recreate what an old pump is "supposed to do" vs what it is "actually doing". Because the flow test is now located at the pump discharge, most AHJ's still want to see a hose allowance somewhere and we will apply it there. It's not accurate, but it is above and beyond and allows for some additional safety margin and makes the AHJ happy.

Wes

8/8/2024 02:22:16 pm

Just as a followup to this, here's the specific code reference that addresses this:

NFPA 13, 2022 Edition, Section 19.1.5: "Water Supplies: Pumps shall be sized to supply the equipment they serve."

If the fire pump does not serve hoses, then it doesn't need to be included for the capacity of the pump. Annex A.19.1.5.3 talks more about this as well.

Leave a Reply.

Home
Our Cause

The Blog
The Forum

PE Exam Prep
The Toolkit
MeyerFire University

Pricing
Login
Support
Contact Us

MeyerFire.com is a startup community built to help fire protection professionals shine.
Our goal is to improve fire protection practices worldwide. We promote the industry by creating helpful tools and resources, and by bringing together industry professionals to share their expertise.

MeyerFire, LLC is a NICET Recognized Training Provider and International Code Council Preferred Education Provider.
All text, images, and media Copyright © 2016-2024 MeyerFire, LLC

We respect your privacy and personal data. See our Privacy Policy and Terms of Service. The views, opinions, and information found on this site represent solely the author and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence.

Discussions are solely for the purpose of peer review and the exchange of ideas. All comments are reviewed. Comments which do not contribute, are not relevant, are spam, or are disrespectful in nature may be removed. Information presented and opinions expressed should not be relied upon as a replacement for consulting services. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a small commission for orders placed elsewhere.

Include Hose Allowance in Fire Pump Size?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES