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


Safety valve Gagging

Safety valve Gagging

Safety valve Gagging

Dear all, Good afternoon !
AS we know for Boiler testing purpose we are doing gagging of Safety valve.
I Search Google for any videos related to it which can put more
light on it but not found.
Can anybody explain in detail or any doc. or video can be share?

Pl. revert.

With regards

RE: Safety valve Gagging

Can you explain in more detail what you're doing.

"testing" can mean many things. If doing this with steam then no, you can't do it.

If you're hydrotesting it after repair and the boiler is physically isolated and your pressure test device has pressure limiting devices then maybe, but there's nothing to go on here.

Is this the same 50+ year old plant / boiler you've been asking questions about before?

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

RE: Safety valve Gagging

Hi GAL02,

IMO your question is more suitable for PSV forum http://www.eng-tips.com/threadminder.cfm?pid=1203 . Of course some of us in this forum have experiences in safety valve.
Agree with LittleInch in regards with the steam and that you should be clear of what you / your plant intentions are. Currently is not.

For example:
What is the testing pressure medium and temperature (P/T)? How many safety valves are you talking here and type? Is it close loop or to atmosphere?
And is this only testing pressure or you want to adjust the safety valve(s) as well?

See some hint from some expert whom have done this http://www.eng-tips.com/viewthread.cfm?qid=180240 . Moral of the story, this is a risky job with some uncertainties, be cautious for operator to position themselves when performing this. If your safety valve is open loop, do not position any parts of someones' body in front or near the outlet
some reference for safety valve in general. http://www.spiraxsarco.com/Resources/Pages/Steam-E...

For gaging as well as adjusting it in relatively safe manner, Trevi-test is one way to do it. similar video by Tru-test https://www.youtube.com/watch?v=gAwS-tjbLeg

Be cautious that you or the commissioning personnel should correspond both safety valves' setting pressure vs the testing pressure. If its gagged (set the screw to prevent it from opening)at X Psi, then the testing pressure is not advisable to exceed 5% of X. this potentially bent the spindle. And if this happened, as per safety regulation the damage parts shall be renewed with UV stamped (read: original) manufacturer parts (if your safety valve manufacturer and your boiler are referring to ASME).

Kind regards,

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected


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!


Research Report: State of IoT Adoption in Product Development 2019
This research report, based on a survey of 234 product development professionals, examines the current state of Internet of Things (IoT) adoption by product design teams, its perceived importance, and what features and capabilities teams consider important when making decision about adding IoT functionality to their products. Download Now
Research Report: Augmented Reality for Maintenance, Repair and Overhaul (MRO)
The term Industry 4.0 denotes a cluster of technologies that’s poised to fundamentally reshape manufacturing and bring about a new industrial revolution. These include 3D printing (AM), the Industrial Internet of Things (IIoT), artificial intelligence (AI) and mixed reality technologies, more commonly known as virtual reality (VR) and augmented reality (AR). 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