ANSI/MSS SP-44-2026: Updated Standard for Steel Pipeline Flanges

The steel pipeline flange industry has received an important standards update with the publication of ANSI/MSS SP-44-2026, Steel Pipeline Flanges.

The revised standard was published by the Manufacturers Standardization Society (MSS) in February 2026 and approved by the American National Standards Institute (ANSI). It establishes requirements for pressure-temperature ratings, materials, dimensions, tolerances, marking and testing of steel pipeline flanges.

One important aspect of the standard is its material requirements. Welding neck pipeline flanges are required to be manufactured from forged steel, while blind flanges may be manufactured from either forged steel or steel plate, subject to the requirements of the standard.

For smaller sizes, dimensional and tolerance requirements are referenced to ASME B16.5. The standard also introduces two Product Specification Levels (PSL). Unless otherwise specified, PSL1 is the default level, while PSL2 includes additional requirements for marking and testing.

What Does This Mean for Flange Buyers?

The updated standard highlights the increasing importance of material traceability, dimensional control and inspection requirements in pipeline projects.

For international buyers, it is important to confirm not only the flange size and pressure class, but also the applicable standard, material grade, PSL requirements, manufacturing route and inspection documentation before placing an order.

For suppliers, compliance with the latest standards can help reduce dimensional discrepancies, documentation issues and potential delays during project inspection.

At Hebei Yu Jinduo, we supply carbon steel and stainless steel flanges according to international standards and customer-specific requirements, supporting projects across different markets with technical documentation and customized specifications.