Hydrotesting after flanged valve replacement 2

[curtis2004]

Hi All,

I have to replace 2"x150# flanged gate valve in compressed aspirating air line to a boiler. This is class 150 line, and flanged valve's yoke is broken. I already know wnat is valve spec, gaskets, studs, nuts, and torque requirements. I have question about hydro testing of piping after replacement of flanged valve. Do I need to conduct full hydro testing or in-service soap test is fine? Is there any code (ASME or API) requirements on conducting tests?
The reason I don't want to do hydro test is I don't have convenient isolation point, drains and vents and don't want to add another ten (10)! valves in order to do full hydro testing.

Thank you,
Curtis

 

[TD2K]

If I needed to, I'd just install two flanges on the valve and hydrotest the valve and then install it. You haven't modified the existing piping, other than replacing a flanged valve, so there is no need to rehydrotest the line.

That said, I doubt I would hydrotest the valve, install the new one and do a leak test.

 

[ytse]

B31.3 para 345.2.3 (b) stated:
"Flanged joints used to connect piping components and subassemblies that have previously been tested, and flanged joints at which a blank or blind is used to isolate equipment or other piping during a test, need not be leak tested in accordance with para. 345.1"
Most valve come already hydrotested by the manufacturer. Just make sure that the valve you are using is tested (per the applicable manufacturing standard).

 

[zdas04]

I was on my way to look for that reference ytse, all I can add is a star.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[curtis2004]

Gentlemen,

I have low pressure 50 psig steam 54" dia. line. Line was built 40 years ago inside power plant of refinery. I need to remove 54" flanged valve and flanges, install spool of piping by butt welding it. There is no other flanged connections nearby to isolate and hydrotest those two new welds. I'm planning X-ray them 100%.Is there anything else can I do?

Thanks,

Curtis

 

[EnergyMix]

Curtis, if the previous answers don't cover your new question, I would recommend asking it as a new thread. A lot of people don't bother coming back to read new posts on old questions that they believe have already been adequately answered.

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