Mercer Valve Pressure Relief Valve 91-43G51V61I1

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 from corrosion or debris

External Surface free from damage

Valve Tag information corresponds to service conditions

If any of the above checks fail, the valve is deemed dangerous to test and should be replaced or repaired immediately

Sign off on the visual inspection

Warning: This procedure requires trained personnel with PPE!

Valves removed from the units and brought to the shop

Valve tested and inspected in the shop

Volume of pressure during testing

Proper assembly of a test bench

Note: The main disadvantage in offsite testing is time

Approximate capacity below the valve when setting for gas/vapor valves

Observation of other valve characteristics (e.g. blowdown)

Volume required for liquid testing

Warning: This procedure requires trained personnel with PPE!

Is the valve accessible for inspection?

If the valve is not accessible, report the issue to the maintenance team and stop the procedure

Is the internal part of the valve observable for visual inspection?

Different methods for leak checking are required if the standard method is not applicable

Are block valves present for set pressure testing?

If block valves are not present, report the issue to the maintenance team and stop the procedure

For dependable performance, PRVs must be maintained regularly.

Mercer Valve Co., Inc. recommends its PRVs are inspected and tested annually.; After the valve has been in installed and a service history has been established, the testing and inspection frequency may be adjusted.

Some guidelines for testing frequencies are found in NB-23, API 576, and API 598.; Additionally, government jurisdiction should be reviewed.; When maintenance is done, qualified repair personnel should perform it.; Qualified repair personnel conducting the annual inspection and testing may alter the maintenance schedule based on the service conditions.

During the inspection, a visual inspection, a set pressure verification, and a leak check should be completed.; These tests can be performed while the PRV is installed on its system or when it’s on a testing bench.; The PRV can only be tested while on its application if there is a method and procedure to apply a controlled pressure to the PRV’s inlet without exceeding any limits of the system.

A visual inspection is used to identify if the PRV is installed properly, is correct for the application, and doesn’t have apparent problems.

Check the nameplate information to verify that the valve is installed on the proper service. A missing nameplate requires immediate addressing.

If the valve is installed on gas/vapor service, the nameplate’s capacity will indicate an air capacity at standard conditions.

If the valve is on liquid service, the nameplate will indicate a water capacity.

Check the seal wire. A broken seal wire indicates that an unqualified person has adjusted the set pressure this also removes any warranty the valve had.

Warning: Only trained personnel should perform this procedure

Valve removed from the application

Thorough inspection of the valve performed

Is the valve transport necessary?

Select the type of mobile test unit used

Note: The limitations of the test stand should be documented and the test stand should only be used for the sizes and pressure that it is designed for

Document the limitations of the test stand

Enter the pressure the valve is designed for