The design of ball valves involves the use of many international standards for producing high-quality products. These standards cover the materials, dimensions, tolerances, and marking for ball valves, ensuring that they can handle the pressures and temperatures they are designed for. Different countries use different standards which makes it important for the manufacturer located anywhere in the world to design and produce the proper product. Essentially, the functional design of the valve is fairly common though the end connections are country-specific or region-specific. For example, the projects executed by American companies normally have NPT threaded valves whereas the projects by European companies have BSP threaded valves. Similarly, the flanged connections on valves follow ASME or DIN standards depending upon American or European contractors. The Japanese have their own flange standards prefixed with JIS.
The British standard BS5351 was used extensively for ball valve design until it was replaced by ISO 17292 standard. API 6D is the American equivalent standard for ball valve design. Both the standards are similar in content except for some minor differences. In India, we generally use ISO 17292 standard in conjunction with ASME B16.34 standard. ISO 17292 provides all the necessary information- namely bore diameters for reduced and full bore ball valves as per pressure classes, the basic structure of ball valves for both floating and trunnion mounted, butt weld end and socket weld end dimensions, ball and stem design, seat selection depending upon temperature, testing procedure, markings on valves, etc. ASME B16.34 standard provides the wall thickness details depending upon the material of construction, pressure class, and temperature of operation of the valve.
There are projects executed by European contractors which have ball valves with DIN flanges. Replacement of DIN flanged ball valves with more commonly available ASA flanged ball valves require one-time replacement of pipeline flanges with suitable ASA flanges.
The distance to be maintained between two pipeline flanges is decided by the face-to-face length of the ball valve. This length is provided by ASME B16.10 standard. Valves manufactured in accordance with ASME B16.10 standards can be fitted and replaced with similar valves onto the pipelines whenever required.
Testing procedure for ball valves prior to dispatch is specified in BS6755 Part 1 and Part 2. BS6755 Part 1 gives the testing procedure for normal ball valves whereas Part 2 gives the Fire Safe Test procedure. Similarly, API 598 provides the required information for valve testing. API 607 provides the Fire safe test procedure.
Other important standards are ISO 5211 which provides the dimensional details for actuator mounting pads provided on valves. NACE MR0175 provides the requirements for crack-resistant material to be used in oil and gas environments containing H2S. ASME B16.11 standard gives the dimensional details for threaded ends, socket weld ends for fittings.
