Mercer Valve Pressure Relief Valve 91-43E51V11C1

Warning: This procedure requires trained personnel with PPE!

Valves removed from the units and brought to the shop

Valve completely 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

Mobile testing units are similar to offsite testing

The valve is removed from the application

This enables a thorough inspection

Mobile testing units can save time because transporting the valve isn’t necessary

Mobile test units are often not set up to test all types and sizes

The testing equipment on a mobile test unit can vary

Some mobile test units have test stands similar to an offsite test stand, allowing for larger valves to be tested accurately

Other mobile test units are set up only for smaller valves

In each case, 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;

Warning: This inspection requires trained personnel with PPE!

The set pressure inspection is performed in accordance with the ASME BPVC.

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.

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

Setting procedures should be in accordance with ASME PTC 25.

The rate of the system pressure increase should be slow when the pressure is within 15% of the set pressure.

The procedures for testing set pressure are as follows.

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 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?