×
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

When is a PSV required?

When is a PSV required?

When is a PSV required?

(OP)
Does anybody know which standard talks about when a PSV is required? My plant has a 1300L desiccant dryer fitted with a PSV, while the other 190L dryer does not.

RE: When is a PSV required?

Equipment fabricated in accordance with ASME pressure vessel code must be fitted with PSV as required in some Code appendix. There would be similar rules with other similar national pressure vessel codes. Firecase PSV is not required for piping.

RE: When is a PSV required?

Also, the pressure equipment may be part of the overall system protected by a PSV, instead of having its own PSV protection.

RE: When is a PSV required?

While the above statements are true, I would like to point out that the need for pressure protection should be based on a quality HAZOP done for all credible system upset and failure scenarios.

Pressure protection can take the form of PSVs, rupture discs, pressure relief panels and frangible roofs...

MJCronin
Sr. Process Engineer

RE: When is a PSV required?

In my experience if you have a pressure vessel with MAWP > 15 psig, you'll likely need to provide a PSV or have calculations on hand showing you considered all the scenarios and the system is protected by design. Some states have size, pressure, and temperature exemptions so maybe the 190L dryer falls into that category (below 150 psig, less than xx dimensions, less than 300F, for example). Alternatively I've had projects where we did calculations showing the dryer was protected by design and an OSHA or NB inspector said "I don't care, add a PSV"

RE: When is a PSV required?

When a pressure vessel is protected by design (ASME Code Case 2211), it may be wiser, faster and less expensive in the long run to put a small PSV on it anyway. My understanding of Code Case 2211 indicates it is quite onerous to meet Code requirements to not have a relief.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

RE: When is a PSV required?

Remember that what is required is a passive layer of pressure protection, NOT A PSV per se. A rupture disk, buckling pin device, or even a liquid leg of sufficient depth are all permitted as relief devices in satisfaction of both ASME VIII's code requirement and, more importantly, good engineering design. Replacing this passive layer of protection with an active layer of protection of similar calculated availability is difficult but possible.

RE: When is a PSV required?

In Alberta, Canada, our jurisdiction (ABSA) has given rules for registering a system that is OPPSD (Overpressure Protection by System Design). See AB-525 for more info.

This of course is only Alberta-specific, but it shows what we do here.

RE: When is a PSV required?

Your PHA will tell you when a PRV is required from a process safety perspective. Equipment design standard (ASME, API, etc.) will indicate when a PRV is required for code requirements. Your local oversight and inspectors (OSHA/NB) will tell you when a PRV is required (or missing) for compliance.

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

3D Scanning in the Automotive Industry
With over 100 years of production history, the automotive industry has been at the forefront of manufacturing technology since its inception. Whether the transformative technology of the day was the assembly line, the integration of robotics into the manufacturing process, or the switch from steel to aluminum frame chasses, the automotive industry has consistently implemented advanced technology into its manufacturing and production workflow to improve manufacturing and product performance. Today, the same is true. Download Now
Green light on lidar: Developing low cost systems for autonomous vehicles
Lidar has been around for quite some time, but to date, it’s been custom—and expensive. Right now, there isn’t a clear-cut solution that’s suitable for all applications, such as lidar in autonomous vehicles. As they explore options, optical and mechanical engineers are forced to make choices and tradeoffs during the design process. 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