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.
Most ball valves used in India come with ASA flanges which have dimensions as per ASME B16.5 standard. This standard provides the dimensions of flanges depending upon the pressure class and size of the valve. Under the ASA regime, the pressure classes are specified by numbers such as 150#, 300#, 600#, 1500#, and 2500#. Each pressure class is suitable for working in a specific pressure and temperature range. DIN standards follow a more straightforward approach. The pressure classes are denoted as PN10, PN16, PN25, PN40, PN100, etc. which represent maximum working pressures in the bar.
