Contact US

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

Different Gauge Reading for Hydrostatic Pressure Test for Hot Water Piping

Different Gauge Reading for Hydrostatic Pressure Test for Hot Water Piping

Different Gauge Reading for Hydrostatic Pressure Test for Hot Water Piping

Hi! I'm currently conducting a hydrostatic pressure test for hot water piping which consisted of a return and a supply line. The covered areas for the tested pipe is from Level 1 to Level 3. For this leak test, cold water is used as its fluid. Attached below is the basic pipe network of our building to give you the idea. At water pumping point is at 175 psi (Gauge No 1)while Gauge No. 2 at the end of Level 1 is at 170 psi. At Level 2 Gauge No.3 is at 145 psi and the Gauge No. 4 at Level 3 is at 140 psi. The specification stated that it should be tested at 175 psi. All 4 gauges have been calibrated. My question is, are there any explanation of whats going on here? I'm expecting the whole pipe network to be at 175 psi. Is it acceptable? If yes, whats the basis of accepting this test? Lastly, is there any formulae of calculating allowable leakage for pressure test with duration of 24 hours?

Thanks in advance.

RE: Different Gauge Reading for Hydrostatic Pressure Test for Hot Water Piping

I suggest you look up the concept of hydrostatic head.

The specification is meaningless without staying at what elevation this pressure is to be held. Highest point or lowest point.

Change of temperature is the only valid reason for a loss of pressure.

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

RE: Different Gauge Reading for Hydrostatic Pressure Test for Hot Water Piping


LittleInch, thanks for your reply. As a fresh grade engineer sometimes I overlooked the basic of fluid mechanics. Its the elevation that cause the pressure difference even within inside the pipe. The specification just mentioned the 175 psi for sectional test (which we have done earlier) and doesn't state at which elevation shall be held. So we'll just ensure that 175 psi to be at the lowest point of the test point while at the top most floor gauge will act as a monitor gauge. If the water was discharge from the top most floor at controlled discharge the bottom gauge would reflect a proportion of the same drop.

Thanks again.

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
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

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