Valve standards come in three main families. API standards set design and testing rules for valves used mainly in oil, gas and petrochemical plants. ASME B16 standards, often still called ANSI, set pressure ratings and dimensions. European EN standards, which replaced most older DIN standards, do the same for European pipework.
Your choice depends on the piping system the valve goes into. A valve must match the flange, the pressure class and the test rules of that system.
API standards
The American Petroleum Institute publishes product standards for each valve type. These are the ones buyers ask for most often:
- API 600 covers bolted bonnet steel gate valves for refinery and process service.
- API 602 covers compact steel gate, globe and check valves in small sizes.
- API 6D covers pipeline and piping valves, such as ball, gate, plug and check valves.
- API 608 covers metal ball valves, and API 609 covers butterfly valves.
- API 594 covers check valves, including wafer and dual-plate designs.
- API 598 covers inspection and pressure testing, explained in the hydrostatic pressure test for valves.
ASME (ANSI) standards
ANSI accredits the standards, but ASME writes the B16 series. ASME B16.34 sets pressure and temperature ratings and wall thickness for steel and alloy valves. It uses pressure classes such as 150, 300, 600, 900, 1500 and 2500.
ASME B16.5 sets flange dimensions up to 24 inches, and ASME B16.10 sets face-to-face lengths. These ensure a Class 300 valve from India fits a Class 300 line built anywhere else.
EN and DIN standards
European pipework uses PN pressure ratings, such as PN 10, PN 16, PN 25 and PN 40. EN 1092 covers flanges, EN 558 covers face-to-face lengths and EN 12516 covers shell strength. EN 12266-1 covers pressure tests and seat leakage rates.
Many older drawings and buyers still quote DIN numbers. A good supplier can map an old DIN reference to the current EN standard. Valves placed on the EU market may also fall under the Pressure Equipment Directive, 2014/68/EU, depending on size, pressure and fluid.
Mixing systems is a common error
A Class 150 flange and a PN 16 flange look similar but do not match. Their bolt circles and bolt counts differ in many sizes. State the flange standard, rating and facing on every order.
Also state the body material standard, trim, end connection and test standard. Read what valves are made in Gujarat to see which types and ratings local plants usually cover.
Who is responsible
The manufacturer designs and tests to the standard. In regulated markets such as the EU, the importer also has duties, such as checking that conformity documents exist. Confirm the rules for your product with your regulator or a notified body.
Next step
We check that your supplier works to the right standard, review its test records and witness tests. Book a free sourcing review to go through your valve list.