To specify a 2 inch ball valve, write down five things: the end connection, the pressure rating, the body and trim materials, the port type and the design and test standard. Leaving any of them open invites a quote for a different valve.
A 2 inch valve is nominal pipe size 2, also written DN 50. The nominal size describes the pipe it fits, not the valve's actual bore.
Which end connection do you need?
Smaller valves often have threaded ends. For threads, state the standard, since BSP and NPT are not interchangeable. Our guide to thread standards: BSP, NPT and metric explains the differences.
Larger or more demanding duty uses flanged ends or welded ends. For flanges, state the standard and the class or PN rating, such as ASME B16.5 class 150 or the EN 1092 PN series, and the facing type.
What pressure rating and standard apply?
Give the working pressure and temperature, and the fluid. Ratings differ for water, steam and gas. The design standard depends on the service. Metal ball valves are covered by standards such as API 608 and ISO 17292, while API 6D covers pipeline valves. Our overview of valve standards: API, ANSI and DIN explains the families.
Test standards matter too. Pressure and leakage tests are commonly done to API 598 or ISO 5208. Ask which one applies, which leakage class the seat meets and whether every valve is tested or only a sample.
Which materials and options should you choose?
Common body materials are brass or bronze for water and air, cast carbon steel for general industrial use, and stainless steel for corrosive or hygienic duty. Seats are usually PTFE or reinforced PTFE. Match material to the fluid, not only to the budget.
Fix these options in the specification:
- Full port or reduced port, since reduced port is common and restricts flow.
- One-piece, two-piece or three-piece body, where three-piece allows in-line servicing.
- Lever, gear or actuator operation, and lockable handles if needed.
- Fire-safe design, if the fluid is flammable, with the matching test standard.
- Material certificates, such as EN 10204 type 3.1.
How do you check a valve before it ships?
Ask for the test report that lists the serial number or batch. Witness a pressure test on a sample. Check the markings on the body, which should show size, rating, material and maker. Operate the valve several times and check that the stem seal does not leak.
For a large order, send a sample to a lab to confirm the body material. A mismatch between a brass body and the alloy you ordered is easy to miss without a test.
Ask also about packing and protection. Valves should ship with the ball in the open position or as the maker advises, with end caps on threaded or flanged ends so dirt does not scratch the seats. Mark the cartons with the designation and heat or batch number so that you can trace a valve back to its test record if a problem appears later. Keep the maker's test report with your own receiving records.
Next step
We shortlist valve makers, check the test reports and witness the pressure test. Book a free sourcing review with your size, rating and fluid.