All valves are inspected and tested by the manufacturer to ensure that they conform to the required valve leakage standards. In addition, optional testing can be requested by the purchaser, and regular testing is critical for ongoing valve maintenance and safety. In many cases it is recommended that valves are tested at an interval of no longer than 12 months. However, the specific interval may vary based on the valve condition, the service condition, and the desired level of performance.

Valve leakage is tested using either a hydrostatic test (i.e., the test medium is a liquid, such as water or kerosene) or a pneumatic test (the test medium is a gas, such as air or nitrogen). Zero leakage is rarely if ever possible, so the standards define the maximum allowable leakage (MAL) for valves under the specified testing conditions.

For both hydrostatic and pneumatic tests, the MAL is usually defined by valve size—a small amount of leakage through a valve with a small effective orifice poses much more risk than would the same amount of leakage through a valve with a large effective orifice. MAL may also be a function of the valve class and pressure category


Control Valve have experienced valve technicians to repair and calibrate control valves from a variety of control valve manufacturers.  Actuators and associated instrumentation are disassembled, inspected, repaired and tested to the manufacturer’s specifications.  New parts are available from inventory.

Control valve inspection, repair and rebuilding can be performed at your facility or within one of our toklai asia bangkok service shops.

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