Mercer Valve Pressure Relief Valve 91-12C11VA7C1

Warning: This procedure requires trained personnel!

Are two pressure gauges used for testing?

Are the gauges reading identical values within their respective tolerances?

Select the type of the first gauge

Select the type of the second gauge

Is the analog (dial) gauge not liquid filled?

Does the digital gauge respond to quick pressure increases?

Do the test gauges have at least 0.25% accuracy over their full scale?

Is the portion of the gauge used more stringent than the set pressure’s tolerance?

Warning: This inspection requires trained personnel with PPE!

Set pressure of the valve verified?

Contact Mercer Valve Co., Inc. for proper leak pressure and specification for the valve

Pressure held steady for a length of time with no observed leakage?

Choose the method used for testing leakage

No bubbles observed for one minute in API 527 test?

No growth of bubbles observed in soap film test?

No bulging of membrane observed in membrane application test?

Warning: This maintenance check requires qualified repair personnel!

Is the PRV correct for the application?

Are there any apparent problems with the PRV?

Is the nameplate information correct?

Is there any damage to the valve?

Are there any issues that would keep the valve from opening or inhibit flow?

Are there any problems found during the visual inspection?

Warning: This inspection requires trained personnel with PPE!

For all valves set 70 psi (500 kPa) and above, the set pressure has a tolerance of 3% of the set pressure

For all set pressure below 70 psi (500 kPa), the tolerance is 2 psi (15 kPa)

If the valve has a CDTP associated with it due to temperature and/or backpressure, the test pressure is checked to the CDTP

Even with a CDTP, the set pressure tolerance is calculated based on the actual nameplate set pressure

The set pressure test should be performed before and after any repairs

The set pressure is inspected to the definition listed in NB-18, a publication by the National Board of Pressure Vessel Inspectors, which is found at http://www.nationalboard.org/

The correct fluid for testing has to be used to achieve accurate results

For gas/vapor service, nitrogen or compressed air is used as the test fluid

Warning: Ensure the valve is not pressurized before starting the inspection

Cap and Seal Wire in good condition

Flanged Connections in good condition

Threaded Connections in good condition

Outlet free of corrosion or debris

External Surface free of damage

Valve Tag information corresponds to service conditions

If any of the above checks fail, the valve should be replaced or repaired immediately

Sign off on the visual inspection