Mercer Valve Pressure Relief Valve 95-90T17092

Warning: This procedure requires trained personnel with PPE!

Upload a photo of the valve before the check

Enter the initial position of the disk

Enter the position of the disk at the fully open position

Enter the minimum lift for certified PRVs from the NB-18 publication

Does the valve meet the minimum lift requirement?

Upload a photo of the valve after the check

Sign off on the valve lift check

Warning: This procedure requires trained personnel!

Are two pressure gauges used for testing?

Are the gauges reading identical values within their respective tolerances?

If the gauges are not reading identical values, both should be checked for calibration.

Does the test gauge 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?

For analog gauges, is only the middle 1/3 or less of the gauge used?

Is each gauge calibrated using a dead weight tester?

Sign off on the monthly gauge calibration

Warning: Only qualified repair personnel should perform this maintenance.

Is there pressure within the main valve or pilot valve?

If there is pressure, remove it before servicing.

Visual inspection: Is the PRV installed properly and correct for the application?

Visual inspection: Any apparent problems with the PRV?

Nameplate check: Is the valve installed on the proper service?

Seal wire check: Is the seal wire broken?

Damage inspection: Any damage to the valve?

Flow check: Any issues that would keep the valve from opening or inhibit flow?

Warning: This inspection requires trained personnel with PPE!

Set pressure of the valve verified?

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

Pressure held steady during the test?

Any leakage observed during the test?

If leakage is observed, report the issue to the maintenance team and stop the procedure.

Choose the method used for testing leakage

Zero bubbles observed for one minute in API 527 test?

- Pressure Relief Valve In Situ Testing

Testing and inspecting in place eliminates the laborious task of removing and handling the valve.

This is especially desirable with large PRVs.

Additionally, not disturbing the existing connections reduces the chance of compromising the existing seals.

This type of testing is very useful when a system cannot be shut down for long lengths of time.

There are disadvantages to this type of testing.

The inspection process is more difficult because the accessibility of the valve is reduced.

The outlet pipe is often still attached and the internal parts are not observable for the visual inspection.

This can also make it difficult to leak check.