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Is it necessary to test PSV after its reseating? 1

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phoenixmoca

phoenixmoca

Chemical
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As the title says after psv reseating are there any regulations, standards and best practices which require the actuated PSV shall be offlined and tested.

Thank you for your answer in advance.
 
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(You mean after opening) Generally no. Some operating companies may require this. Some may require it if the PRV is found to be leaking badly after the event. PRV installed properly should be capable of a few openings without need to retest. They should never open either if the system is safely run.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.
 
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Foe US facilities there is a governmental regulation (EPA - Environmental Protection Agency) that requires PSV inspection/testing in certain specific chemical services, after the PSV has opened. This only applies to those specific chemical services. For all other cases, including those in facilities outside the US, I'm not aware of any requirement to pull the PSV for inspection/testing after it has activated. This decision is left to the user. Obviously, the key considerations are the service fluid, and whether or not the PSV is leaking. In most cases there's no need to pull the PSV unless it is found to be leaking.

An o-ring (soft seat) will greatly reduce the tendency of a PSV to leak after it has opened.
 
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When the PSV is in fouling fluid service, there is a high probability of the PSV leaking after reseating. When the PSV is in clean fluid service, it is likely the PSV may not leak after reseating. On the other hand, operators will be reluctant to take a PSV offline for cleaning and recalibration after reseating if there is no inline standby PSV. Process safety concerns may arise if there are two or more PSVs' leaking, with some bearing water vapor, while others are cold.
 
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Our normal practice is once the PSV pops at site & seat back properly without any leakage, then we will not remove the PSV to RV shop for calibration. However, if its leaks, then it will be removed for calibration. As per Saudi Aramco PSV Procedure(SAEP-319) there is no such requirements explained in the procedure. But, we will investigate the reason for PSV Popping. More than 7500 PSVs available in our plant.
 
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PSVs, often and in most countries, come under statutory laws and need to be tested at regular intervals, varying from 6 months to 1 / 2 years.

Often there are two PSVs installed on the same vessel, column, steam drum, horton sphere with isolation to meet statutory obligations.

Now, PSVs do pass during service and if the loss is acceptable or within limits, say hydro-carbon being flared or steam being released to atmosphere, could be tolerated, life goes on.

PSVs are meant to actuate / pop in an over-pressure situation and to test each of them after such an event is gross!

Unless, it is statutory, of course.

DHURJATI SEN


 
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Thank you all for your kindly reply.

According to your reply I have summarized as below,

1. If no leak it is unnecessary to pull the actuated PSV offline
2. If the regulation requires it must be offlined to recheck
3. It depends on the fluid property

So my question is how to check whether it is leaking after reseating.

Is there any reference in which what kind of fluid have impact on the PSV performance, such as viscosity, polymerization, corrosion and so on?AND what is the threshhold value of the fluid properties(for example viscosity), beyond which it shall pull PSV offline?

Thank you all again.
 
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Worth noting here that a few of the big established PRV manufacturers now offer wireless 'Smart Valve' technology. Options include monitoring the PRV tightness before and after lifting, date stamping opening events etc.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.
 
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phoenixmoca said:
So my question is how to check whether it is leaking after reseating.

Is there any reference in which what kind of fluid have impact on the PSV performance, such as viscosity, polymerization, corrosion and so on?AND what is the threshhold value of the fluid properties(for example viscosity), beyond which it shall pull PSV offline?
Click to expand...

For the first question, inspect it visually, and/or use a chemical detector tube (e.g. Drager tube). The second question is a risk management decision for each user to make - there's no fixed ("cook-book") answer. Assess the specific case based on the fluid's potential for plugging, corrosion, etc., and then decide the best response based on your assessment of that specific application.
 
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