Required Pipeline IDs for Flow Measurement Pressure-Temperature Compensation

by | Aug 7, 2013 | Measurement Instrumentation, Temperature

Jim Cahill

Chief Blogger, Editor

I received a call the other day and wanted to capture the question and answer for other people Googling around with similar questions. The question:

What are the required distances in pipeline inside diameters (I.D.) upstream and downstream for a differential pressure (DP) flowmeter for the pressure and temperature sensors doing pressure-temperature (PT) compensation?

I turned to my friends on the Rosemount DP Flow Specialist team. Emerson’s Vernon Binger responded:

3051SFC_P_Wireless_L_ProdImageIt is common to take the line pressure (static pressure) measurement at the same port for the upstream DP measurement; a “tee” fitting can be used.

This is compliant to ASME practices per the ASME MFC-3M standard, and therefore compliant to U.S. Environmental Protection Agency (EPA) requirements.

If a separate tap location will be used for the line/static pressure measurement, then it should be at least 1 pipe diameter upstream from the tap used for the upstream DP measurement. This tap location should be offset 30 degrees radially from the upstream DP tap location.

The line/static pressure tap in the process pipe should be ≤0.50″, and <0.13 x pipe I.D.

The temperature probe/thermowell should be installed at a location between 5D to 15D downstream from the orifice plate or other primary element. That is, unless the temperature measurement is done as an integral part of the primary element, such as the integral RTD option on the 405 Compact Primary element, or the 485 Annubar.

Vernon and I received a note back from the person who asked me the question:

That was precisely what I needed. Thanks very much.

I hope this also helps you if you found this post in your search. Leave me a comment if it did… thanks!

Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Subscribe for Updates

Follow Us

We invite you to follow us on Facebook, LinkedIn, Twitter and YouTube to keep up to date on all the latest news, events and innovations to help you take on and solve your toughest challenges.

Want to re-purpose, reuse or translate content?

Please do, Just link back to the post and send us a quick note so we can share your work. Thanks!

Our Global Community

Emerson Exchange 365

The opinions expressed here are the personal opinions of the authors. Content published here is not read or approved by Emerson before it is posted and does not necessarily represent the views and opinions of Emerson.