Mercer Valve Pressure Relief Valve 95-80R15033

Warning: This inspection requires trained personnel with PPE!

Set pressure of the valve verified?

Note: Leak test pressure should be 90% of the set pressure or 5 psi below the set pressure, whichever is greater.

If the valve has a CDTP, the leak test pressure will be below the CDTP in lieu of the set pressure.

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

Pressure held steady during the test?

Any leakage observed during the test?

Select the method used for testing leakage

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: This procedure requires trained personnel with PPE!

Upload a photo of the lift checking apparatus

Enter the measurement of the movement of the disk from the closed position to the fully open position

Enter the minimum lift for certified PRVs as per NB-18 publication

Does the lift meet the minimum requirement?

Sign off on the pressure relief valve lift check

During the set pressure inspection, the set pressure is verified in accordance with the ASME Boiler and Pressure Vessel Code.

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

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

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 (if it passes the visual inspection) 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/.

This publication lists all ASME Boiler and Pressure Vessel Code certified pressure relief valves.

It indicates the correct set pressure definition and other characteristics of a valve.

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

Cap and Seal Wire in good condition

Flanged Connections in good condition

Outlet free of corrosion or debris

External Surface free of damage

Valve Tag information corresponds to service conditions

Two tags present on 9500 Series valves

If the valve fails any of the above checks, do not proceed with set pressure inspection and leak inspection

Sign off on the visual inspection