What is the significance of ASME B16.34 compliance for valves?
The ASME valve standard B16.34 “Valves Flanged, Threaded and Welding End” is a valve standard accepted worldwide by end-users, engineering contractors and manufacturers as the fundamental basis for valve design, testing and performance. This standard covers new construction including pressure-temperature ratings and dimensions for cast, forged, and fabricated flanged, threaded, and welding end, and wafer or flangeless valves.
More than 20 years ago, back in 1988, the scope of this standard was changed to include also threaded-end and weld-end valves in addition to flanged-end valves. It is often used as a minimum requirement when purchasing valves on the international market where, as we all know, construction quality can differ significantly, often reflected in the purchase price.
Also other standards like ASME B31.1 “Power Piping Design” and ASME B31.3 “Process Piping Design” refer the user to ASME B16.34.
But what does compliance to B16.34 exactly mean ?
- Body & shell materials comply with ASME and ASTM material standards for chemistry and strength.
- Body & shell materials are heat-treated to insure proper grain structure, corrosion resistance and hardness.
- Wall thicknesses of body and other pressure-containing components meet ASME B16.34 specified minimum values for each pressure class.
- NPT and SW end connections comply with ASME B1.20.1 or ASME B16.11.
- Stems will be internally loaded and blowout proof.
- All bolting will be ASTM grade with maximum applied stress controlled by B16.34.
- Each valve is shell tested at 1,5x rated pressure for a specific test time duration.
- Each valve is tested for seat leakage in both directions for a specific test time duration.
- Each valve is permanently tagged with materials of construction, operating limits and name of manufacturer.
When purchasing valves according to ASME B16.34 it is advised to check with the supplier if they are really in full compliance with this standard.