Pressure Relief Devices

[SBlowers]

I am working in the Middle east for a contracting company. My client needs the Pressure relief devices to be visually inspected (in-service) every year. Our Onstream inspection program is every two years which cover pressure relief devices as well. Is there any mandatory requirement to inspect in-service pressure relief devices annually? We have a 5 yearly PRD testing/overhauling frequency.

thanks...SB

 

[zdas04]

You answered your own question.

My client needs the Pressure relief devices to be visually inspected (in-service) every year

If you are looking for support for telling your client that his perfectly legal requirements are wrong, good luck with that. The regulations and recommended practices for inspections are minimum requirements. If a company wants to go above and beyond those minimum requirements then it is an issue for that company's risk/reward analysis not for a contractor to arbitrarily question. If they were stretching their inspection frequency farther than the code allows then you would have an obligation to point it out to them, but to satisfy the code and go beyond is not your business.

David

 

[SBlowers]

David,

I agree to your point and understand client's requirement.

My query was to check whether the API code specify annual in-service inspection requirement for Pressure relief devices.

This is not to argue or teach my point to the client!

Cheers....SB

 

[JAlton]

NBIC, Part 2.5.8 (f) & (g), has a requirement for Inservice Inspection of Pressure Relief Devices which varies depending on the Service Fluid. "Inspection frequency should be based on previous inspection history. If valves are found to be defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection results are obtained. Where test records and/or inspection history are not available, the following inspection and test frequencies are suggested.
Service Inspection Frequency
Steam Annual
Air and Clean Dry Gases Every three years
Pressure relief valves in
combination with rupture disks Every five years
Propane, Refrigerant Every five years
All Others Per inspection history

g) Establishment of Inspection and Test Intervals
Where a recommended test frequency is not listed, the valve user and Inspector must determine and agree on a suitable interval for inspection and test".

JAC

 

[MortenA]

Dont disregard that you are not in the US - and no matter how stupid this may seem there may be local rules and regulations and that these may not be similar to the US rules on this subject. Believe it or not - US rules does not (implicit) apply outside of the US...

Best regards

Morten (living where CE rules)

 

[robsalv]

I'm a bit confused. You seem to be mixing the pressure equipment and pressure relief equipment together. This should only be the case if you do not have an inlet block valve on the PRV, otherwise you should be able to manage the two seperately.

On the topic of an annual visual inspection, what are you going to visually inspect about the PRV?? Cluey operators who know their plant SHOULD report passing PRV's for maintenance follow up.

For an American flavour to your thinking, API RP576 has guidelines for setting PRV service intervals, but I don't believe there's anything about an annual visual. You'll also want to review API510 for pressure vessel inspection requirements.


Broadly though, the maximum service interval depends on the the fluid service and service history. If you have deep enough pockets though, you can overservice them more regularly if desired.

- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."

 

[edanyel]

My client needs the Pressure relief devices to be visually inspected (in-service) every year. Our Onstream inspection program is every two years which cover pressure relief devices as well.

My opinion is that none of the international codes, API, ASME, NBIC, say nothing about visual inspection intervals.
You can look at your client's PSVs everyday if you like but that tells you nothing.

My query was to check whether the API code specify annual in-service inspection requirement for Pressure relief devices.

That is different , you have suggestions to that in all of them, saying in several ways that the best interval is the one that assures you a PSV won't fail to open in any case. (that´s why you need to know the histoy of development to determine intervals). If no history is available, then see the service conditions (clean, fouling, critical).

One year is too often or not, five years is too long or not, depending on service conditions and valve history.

Finally, if you offer test/repair every five years, what do you offer to do on a PRD every two years?

Bst rgds
Daniel

 

[JAlton]

edanyel is correct. Without a repair history, it is impossible to determine the optimal repair/inspection frequency. See NBIC "Inspection frequency should be based on previous inspection history. If valves are found to be defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection results are obtained...". I know of PRV Users who accept a visual inspection (external). I do not agree with this option because it is impossible to look at the outside of a PRV and determine the acceptability of the Set Pressure or other important PRV Performance Characteristics.

JAC

 

[robsalv]

Does the NBIC factor in the "as received" condition of the PRV in the determination of the subsequent inspection frequency?? i.e., if the PRV is scaled/rusty & dirty, but popped well and didn't have a low bubble/initial leak pressure, would the subsequent inspection cycle determination be impacted??



- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."

 

[edanyel]

Robsalv, at our plant, we take the outside conditions of the prv as part of the issues to be taken in account when determining the next interval.

For example, let's say very good results in test stand lead us to a 5 year interval, but corrotion in bolts and nuts may put us in trouble within three of four years.

Rgds
Daniel