MeyerFire
  • Blog
  • Forum
  • THE TOOLKIT
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR*
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND*
    • FIRE FLOW CALCULATOR*
    • FIRE PUMP ANALYZER*
    • FIRE PUMP DATABASE*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER*
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR*
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'22)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • QUICK RESPONSE AREA REDUCTION
    • REMOTE AREA ANALYZER*
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • SYSTEM ESTIMATOR*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER STORAGE*
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • UNIVERSITY
    • ABOUT
    • CATALOG
    • CONTENT LIBRARY
  • PE Exam
    • PE Forum & Errata
    • PE Store
    • PE Tools
    • PE Prep Series
    • PE 100-Day Marathon
  • LOGIN
  • PRICING
    • SOFTWARE & TRAINING
    • STORE
  • THE CAUSE
    • ABOUT US
    • BECOME AN INSTRUCTOR
    • HELP/SUPPORT
Picture

Maximum Allowable Pressure for Fire Hydrant?

8/1/2022

9 Comments

 
We have a proposed fire hydrant in our county that will have pressures ranging from 210 psi to 250 psi according to the engineer designing the underground line.

My Chief and I are looking into this in regards to NFPA standards/applicable code, and are concerned that the high pressure could injure firefighters or damage equipment.

Is there a maximum permitted pressure that a hydrant can be, per code?

Thanks in advance.

​​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
9 Comments
Alex
8/1/2022 06:54:37 am

Hi,

Is the hydrant downstream of a fire pump or part of a combined standpipe system?

NFPA 24 (2019) A.10.1.2 states "systems that do not incorporate a fire pump or are not part of a combined standpipe system do not typically experience pressures exceeding 150 PSI in underground piping."

Materials used for an underground system are rated for no less than 150 PSI. If you are exceeding 150, ensure that all pipe materials are cleared called out to handle the additional pressure. There is no maximum pressure listed in NFPA 24.

I would ensure you are within your operating range of all components, of all apparatus, within your department. For example, my call department has an engine with an intake valve with a maximum of 250 PSI.

Thanks,
Alex

Reply
chad
8/1/2022 08:12:57 am

I concur with Alex.

We have the same issue with a large industrial facility that has all its yard hydrants and sprinkler riser fed from the pump off the same main fed from municipal water (its old). we get 190-200 PSI out of hydrants and cant adjust relief valves high enough to keep them from operating. But the trucks can safely handle it.

Unfortunately they need that head pressure to overcome FL for the sprinkler due to distance and elevation. No one has the willingness to make them split the yard hydrants off on a separate line with a PRD.


Is it only 1 hydrant like this? You didn't say hydrants.

Reply
Glenn Berger
8/1/2022 08:11:01 am

Delivered pressure of 210 to 250 psi is way to high. Need to ensure that the hydrants provided can support that pressure and that the Fire Department approves.

Sounds like the project is installing a long distance water transmission pipeline. Fire Hydrants should never be installed on these pipes.

Reply
Greg
8/1/2022 08:35:14 am

I'm in agreement with Glenn that the pressure is too high. My experience with similar pressures as noted by Glenn was in a transmission type pipe in Nevada. The water's source was elevated in a nearby mountain range and the main transmission piping network had very very high pressures. The water sent to the fire hydrant networks required pressure reduction.

The top pressure number in the question, 250psi, I believe is the rated pressure limit for many standard hydrants. Reducing to 200 or below with a goal of 175psi is something that is manageable.

How to accomplish the reduction feels more like municipal water equipment than traditional fire water supply equipment but likely there is someone here who can call out a make and model that speaks to the question.

Reply
Aaron
8/1/2022 09:14:01 am

As an engineer who has decades of municipal and private experience with transmission, distribution and point of use I can say that something sounds quite off here.

My first question is why is a hydrant being proposed at this location to start with...is there a structure at risk or is it to adhere to a blanket spacing requirement along a new public line?

The second question is in line with what others have mentioned...this sounds like a transmission main which in principal is not tapped except for installation of a master meter (which will include pressure reducing valves) to a secondary pressure zone. This secondary zone would then have distribution piping onto which hydrants would be installed.

IF for some special reason this singular hydrant is indeed intended to be installed on this high-pressure main, all fittings and pipe must be minimum Class 250 rated, and I would recommend the installation of a FM-rated double detector check valve assembly followed up by a pressure reducing valve assembly with a FDC and/or ground hydrant for connection.

All of this new infrastructure will require protection from freezing as well as being located in a secure location to avoid vehicular impact (including brush hogs if in the ROW).

If you have additional details on the application we can provide a more tailored approach.

Fred walker
8/1/2022 10:13:59 am

There are some cities like Baltimore and San Francisco (there are others) which operate high pressure / high volume fire protection water distribution systems separate from the potable distribution systems. Some of these are capable of pressures you have indicated.

As well there are industrial fire protection water distribution systems capable of similar pressures.

One option would be to require intake relief valves designed for a greater pressure range than standard off the shelf relief valves.

Reply
Jesse
8/1/2022 01:45:35 pm

I concur with Alex. This is too high

Reply
Dwight
8/1/2022 07:02:59 pm

Ever been on the business end of a manual hose line with 175 psi on it? It is not fun, and totally unproductive. In fact, it is on the borderline of dangerous. For fixed appliances it can work, but not for a mixture of the two (manual and fixed). For manual firefighting the nozzle pressures typically vary between 50 psi for straight bore and 100 psi for fog tips. Even at a supply pressure of150 psi, your discharge pressure from the engine will be about 175 psi, at idle.

I had one case where the design engineer oversize the pressure output of a stationary fire pump feeding a large standpipe system. He refused to downsize the pump and instead installed a pressure regulating valve, adding significant complication to the system that didn't need to be there, and the need for additional inspection, testing and maintenance maintenance for the life of the system.

Reply
Jay
8/2/2022 10:45:41 am

Our fire engines have intake relief valves set at 145psi, so that's something you'll want to look into cause you'll be dumping water like crazy. Also think about the LDH you'll be using to connect the hydrant to the pumper.....what is its maximum working pressure?

Reply



Leave a Reply.

    Picture
    Why Sponsor?

    ALL-ACCESS

    Picture
    GET ALL OUR TOOLS

    SUBSCRIBE

    Subscribe and learn something new each day:
    I'm Interested In:

    COMMUNITY

    Top ​Feb 2023 Contributors
    Picture
    Picture
    Picture
    Picture
    Picture
    Picture
    Picture
    Picture
    Picture
    Picture
    SEE LEADERBOARD

    YOUR POST

    SUBMIT A QUESTION

    PE EXAM

    Get 100 Days of Free Sample Questions right to you!
    SIGN ME UP!

    FILTERS

    All
    A117.1
    ABA
    ADA
    ASCE 7
    ASME A17.1
    ASTM E1354
    Daily Discussion
    Design Documents
    EN 12845
    Explosion Protection & Prevention
    Fire Detection And Alarm Systems
    Fire Dynamics
    Flammable & Combustible LIquids
    FM Global
    Human Behavior
    IBC
    ICC-500
    IFC
    IMC
    IPC
    IRC
    ISO
    Means Of Egress
    NBC
    NFPA 1
    NFPA 10
    NFPA 101
    NFPA 11
    NFPA 110
    NFPA 1142
    NFPA 1221
    NFPA 13
    NFPA 13D
    NFPA 13R
    NFPA 14
    NFPA 15
    NFPA 16
    NFPA 17A
    NFPA 20
    NFPA 2001
    NFPA 214
    NFPA 22
    NFPA 220
    NFPA 24
    NFPA 241
    NFPA 25
    NFPA 291
    NFPA 30
    NFPA 30B
    NFPA 33
    NFPA 400
    NFPA 409
    NFPA 415
    NFPA 495
    NFPA 497
    NFPA 5000
    NFPA 502
    NFPA 54
    NFPA 55
    NFPA 654
    NFPA 68
    NFPA 70
    NFPA 701
    NFPA 72
    NFPA 75
    NFPA 770
    NFPA 82
    NFPA 855
    NFPA 90A
    NFPA 92
    NFPA 96
    NICET
    OBC
    Passive Building Systems
    PE Prep Guide
    PE Prep Series
    PE Sample Problems
    Poll
    Smoke Management
    Special Hazard Systems
    UFC 3 600 01
    UFC 3-600-01
    UFC 4-021-01
    Updates
    Water Based Fire Suppression
    Weekly Exams


    ARCHIVES

    March 2023
    February 2023
    January 2023
    December 2022
    November 2022
    October 2022
    September 2022
    August 2022
    July 2022
    June 2022
    May 2022
    April 2022
    March 2022
    February 2022
    January 2022
    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    November 2016
    October 2016
    July 2016
    June 2016


    PE PREP SERIES

    Fire Protection PE Exam Prep
    SEE LEADERBOARD

    RSS Feed

Picture
​Home
Our Cause
The Blog
The Forum
PE Exam Prep
The Toolkit

MeyerFire University
​Pricing
Login
​Support
Contact Us
Picture

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 an International Code Council Preferred Education Provider.

All text, images, and media ​Copyright © 2023 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.

  • Blog
  • Forum
  • THE TOOLKIT
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR*
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND*
    • FIRE FLOW CALCULATOR*
    • FIRE PUMP ANALYZER*
    • FIRE PUMP DATABASE*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER*
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR*
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'22)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • QUICK RESPONSE AREA REDUCTION
    • REMOTE AREA ANALYZER*
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • SYSTEM ESTIMATOR*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER STORAGE*
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • UNIVERSITY
    • ABOUT
    • CATALOG
    • CONTENT LIBRARY
  • PE Exam
    • PE Forum & Errata
    • PE Store
    • PE Tools
    • PE Prep Series
    • PE 100-Day Marathon
  • LOGIN
  • PRICING
    • SOFTWARE & TRAINING
    • STORE
  • THE CAUSE
    • ABOUT US
    • BECOME AN INSTRUCTOR
    • HELP/SUPPORT