Testing FREON relief valves 1

[jeevesme]

We have our relief valves pop tested at certain intervals depending on service. We have some valves that are in Freon service that are replaced every 5 years. We also pop test these after they are removed to see if they would have relieved at the set pressure. We have some valves that were tested recently and all of the initial pops ranged from 111%-128% of set pressure which triggers an investigation. The was no corrosion or visual issues seen with them before popping. We use two companies for testing and they both use Air to test valves that are in Freon service.

Question 1: Since these are designed for Freon service, will testing them using Air be accurate?

Question 2: Is there some sort of conversion chart that we can reference when testing Freon valves?

Any questions, comments, and thoughts would be welcome. And thank you in advance.

 

[Latexman]

Pressure is pressure. Air (gas/vapor) and water (liquid) is used to test a LOT of PSVs all over the world.

I would look elsewhere for the set pressure deviation you are seeing.

Good Luck,
Latexman

 

[The Obturator]

Depending on the manufacturer/model no/set pressure etc., were the valves tested acc. to the manufacturers instruction manual? An often overlooked issue, is adjusting the nozzle ring settings for bench testing Vs actual service/installation settings. 5 Years also looks like a short period for replacing the valves, but would be a long period in between testing - it is always recommended that such testing intervals are developed over time with results etc., recorded to determine the best interval for the application. It might be that every 2 years would be better, but there are many factors that would need to be considered over time to get to that point.


*** Per ISO-4126, the generic term
'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***

 

[MJCronin]

What did the relief valve manufacturers tell you when you called them ???



MJCronin
Sr. Process Engineer

 

[LittleInch]

Replaced every 5 years???
What did the results of the more regular testing tell you?
When was the last one before removing it and testing in air?

Did they star to simmer before "popping"?

size and amount of air available might be an issue, but seems unlikely.

How big are we talking here?

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