Which standard is used for flange class marking?

Which standard is used for flange class marking?

• A. API 570
• B. ISO 9001
• C. ASME/ANSI B16.5
• D. ASTM A105

Answer: (C)

The main idea is identifying flanges consistently so you can trust they will mate safely in a piping system. Flange class marking is defined by ASME/ANSI B16.5, which specifies the dimensions and the way a flange’s rating is marked. This standard sets the pressure–temperature class shown on the flange (like 150, 300, or 600) and ensures that flanges from different manufacturers carrying the same class will be compatible in terms of fit and strength. It also covers the related details that appear on the flange, such as bolt pattern and identification marks, so inspectors can quickly verify the right component is used for a given service. Other standards don’t govern flange class marking. ISO 9001 deals with quality management systems, not how flanges are marked. API 570 focuses on inspection and maintenance of piping systems rather than marking conventions. ASTM A105 is a material specification for forged carbon steel used to manufacture flanges but does not define the marking standard itself.

The main idea is identifying flanges consistently so you can trust they will mate safely in a piping system. Flange class marking is defined by ASME/ANSI B16.5, which specifies the dimensions and the way a flange’s rating is marked. This standard sets the pressure–temperature class shown on the flange (like 150, 300, or 600) and ensures that flanges from different manufacturers carrying the same class will be compatible in terms of fit and strength. It also covers the related details that appear on the flange, such as bolt pattern and identification marks, so inspectors can quickly verify the right component is used for a given service.

Other standards don’t govern flange class marking. ISO 9001 deals with quality management systems, not how flanges are marked. API 570 focuses on inspection and maintenance of piping systems rather than marking conventions. ASTM A105 is a material specification for forged carbon steel used to manufacture flanges but does not define the marking standard itself.