Just as people require certain qualifications to perform specific tasks, so does instrumentation, final control elements, control systems and other components in an automation architecture.
In a very informative Chemical Engineering Progress (CEP) article, Purchase a Qualified Valve for Your Operation, Emerson’s Jason Jablonski highlights numerous qualification standards and criteria for control and isolation valves.
Jason opens highlighting the importance of using the right valve for the intended application.
Proper valve operation is necessary to prevent hazardous fluid releases, equipment damage, and unstable plant control, all of which can be dangerous and costly.
The qualification process is dictated by the standard to which it is trying to adhere. Most standards testing specifications:
…require that a third-party witness attend, observe and document the tests.
Equipment for this testing can include:
…bunker and hydrostatic pumps, heat tape and insulation, thermocouples, torque and force meters, fluid leak meters, and mass spectrometers for evaluating fugitive emissions.
Typical documentation:
…includes general assembly drawings, calculations, material certificates, parts lists, references, and other miscellaneous information related to internal equipment and processes.
These test reports given to suppliers and shared with their customers are used by the customers to add the manufacturers’ control and isolation valves:
…to the approved manufacturer’s list (AML) for that product category. Depending on the specification, recertification may be required on a regular basis, such as every five years.
Jason lists numerous valve standards with a description of their coverage. These standards include: API [American Petroleum Institute] RP 591, API 598, API 599, API 600, API 602, API 603, API 608, API 609, API 623, API 624, API 641, ASME (American Society of Mechanical Engineers) B16.5, ASME B16.10, ASME B16.34, ANSI/FCI (American National Standards Institute/Flow Control Institute) 91-1, ISO (International Organization for Standardization) 15848, Shell MESC (Material and Equipment Standards and Code) 77/300, Shell MESC 77/312.
These standards address many areas of valve qualification testing including limited sample sizes, limited material options, limited testing conditions, testing subjectivity, variation and consistency, and changing standards.
Jason highlights some of the production performance testing performed on valves from Emerson. These can include seat leakage detection, valve stroke times, hydrostatic pressure testing, and valve signature (calibration curve) plots.
Read the article for much more on tests around production, seat leakage, stem packing, fugitive emissions, pressures, and cavitation/flashing/noise control, and more. You’ll come away much wiser about the qualification testing performed to assure the control or isolation valve meets the requirements for your application.
Visit the Valves, Actuators & Regulators section on Emerson.com for more on the best valve for your application. You can also connect and interact with other valve experts in Valves, Actuators & Regulators group in the Emerson Exchange 365 community.
