×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Relief Valve Installation and Sizing Basis?

Relief Valve Installation and Sizing Basis?

Relief Valve Installation and Sizing Basis?

(OP)
I am reviewing the sizing and installation of several RV's and have the following questions:

1. Can a Relief Valve be installed on the outlet piping of the vessel it is protecting?  Common sense would say yes, as long as the pressure vessel does not add any addition pressure drop.  What if the vessel is a filter or exchanger?  Is there anything in the code about this?

2.  When sizing a RV for a control valve failure, do you HAVE to ignore the associated piping and look only at the CV of the valve?  I have a RV that is too small when looking at the CV of the valve; can I look at the entire system and recalculate the max flow through the valve and piping and see if the RV is okay?

Thanks,

Matt

RE: Relief Valve Installation and Sizing Basis?

A RV can be located at the outlet piping of the pressure vessel provided the pressure drop from the vessel to the PV does not exceed 3% of the PV set pressure.  Also there should not have any internal that can block the PV e.g. mass pad, valve, etc.

When sizing PV for control valve failed open,  I normally ignore the pressure drop through the piping.  Usually it is insignificant.  

May be I can advise you but need the following information.  
1.  the design pressure of the vessel,
2.  operating pressure of the upstream equipment,
3.  do you have any SDV between the pressure vessel and the upstream equipment.
4.  What is the application, flamable gas/liquid, toxic,
5.  onshore/offshore and where.

RE: Relief Valve Installation and Sizing Basis?

SooCS:

Excellent & concise response!
I believe you meant to write "mesh" instead of mass; but the intent is understood by me and, I hope, byrdo.

byrdo:
You ask about filters and I just want to make sure that you understand the concept that SooCS has pointed out: a clogged or plugged filter (or any internals, for that matter) can present a hazardous overpressure to the vessel where it resides.  Therefore, you must protect the vessel upstream of the potential plug and your proposed line PSV.  That why SooCs brings up the mesh pad(s) -which are similar potential plugs.

These are very important subjects that should be well-understood and conceived by all design and operating engineers.  

Art Montemayor
Spring, TX

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!


Resources