Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Pipe loss

Pipe loss

Pipe loss


Which one is correct a or b.. Considering all 4 nozzles should discharge 5 gpm at 10 psi of pressure simultaneously...

RE: Pipe loss

Neither, but B is closer.

Sprinklers are variable flow depending on pressure, so in B the first sprinkler will flow more than 5 gpm which impacts on flow.

Also if those sprinklers are evenly spread, the pressure drop will vary as the flow goes down.

The best way is to either do iterations or design a a larger header pipe to reduce frictional loses.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Pipe loss

If your pressure drop estimates are correct then the nozzle pressures will be 13, 12, 11, 10 and the flows will be whatever correspond to those pressures. And the source pressure will be 15.
The only way around this is to make the header large enough so that there is no pressure drop between nozzles. Or a large header and then equally restrictive drops to each nozzle.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Pipe loss

@littleinch thankyou.. Actually I don't need the nozzles to discharge 10 psi.. Was making an excelsheet for Darcy wisebach method pressure drop calc. And got curious if for example there are 10 nozzles and each needs 10 psi so do we need to multiply the pressures.. Thanks for clarifying

@edstainless.. Nice explanation.. Thanks

RE: Pipe loss


Instead of building a spreadsheet, you might want to try EPANET, which is free water modeling software: https://www.epa.gov/water-research/epanet

EPANET can use Darcy, Hazen-Williams, or Mannings for pipeline hydraulics and can model emitters for fire protection systems and irrigation systems. EPANET doesn't have all the bells and whistles that the commercial programs have (many of which use EPANET as the calculation engine), but it's a lot more usable and flexible than a spreadsheet can ever be.


"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

RE: Pipe loss

No you do not multiply. You size the pipe, adding flow from each sprinkler, so that at least 10psig is available at each sprinkler.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now
The Great Project Profitability Debate
A/E firms have a great opportunity to lead the world into the future, but the industry’s greatest asset—real-time data—is sitting wasted in clunky, archaic ERP platforms. Learn how real-time, fully interactive dashboards in a modern ERP allow you to unlock data that will shape the future of the world. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close