EN 10253-2 Type A vs Type B: What Procurement Engineers Must Know
When specifying European buttweld pipe fittings, one question consistently causes confusion on tender documents: Type A or Type B?
The Standard
EN 10253-2 covers wrought stainless steel and nickel alloy buttweld pipe fittings. It defines two dimensional series — referred to simply as Type A and Type B — primarily distinguished by wall thickness and bore geometry.
Type A vs Type B
Type A is the lighter-wall series. Wall thickness corresponds broadly to ASME B16.9 dimensions for the equivalent nominal pipe size and schedule. Bore is not machined to match a specific pipe bore — it is a nominal bore.
Type B is the heavier-wall series. The bore is precision-machined to match the inside diameter of a specific pipe (per EN 10216-2 or EN 10217-2), ensuring flush, turbulence-free joints. The heavier wall gives a higher pressure rating under EN 13480 (European Industrial Piping Code). Type B also requires a longer weld bevel preparation area.
Which to Specify
For European projects designed to EN 13480 and subject to PED 2014/68/EU, the default is almost always Type B. It is pressure-rated directly against the pipe schedule and provides a flush bore for in-line inspection (pigging, ultrasonic). Type A is acceptable where the piping system is designed to ASME B31.3 (as in many offshore and oil & gas projects) and the end user accepts ASME-equivalent dimensions.
Mixing Type A and Type B in the same piping system is not recommended — bore mismatch at joints creates flow turbulence and complicates in-service inspection.
Certificates
EN 10253-2 mandates EN 10204 3.1 inspection certificate as minimum. High-pressure or PED Category III applications typically require 3.2 (third-party countersignature). Always state "EN 10204 3.1" or "EN 10204 3.2 TPI" explicitly on the purchase order — generic "mill certificate" language is ambiguous and may result in a 2.2 test report being supplied.
Common Procurement Errors
Many suppliers from India and the Middle East quote "EN 10253" without specifying Type A or B. Always confirm: ask for the fitting dimensional datasheet and verify that wall thicknesses match the EN 10253-2 Type B schedule for your pipe OD and wall. Arshya Pipe Fittings manufactures exclusively to Type B — the heavier schedule — as standard.