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Common standards include:
Flanges can be welded or screwed on, depending on the type of flange and piping system requirements. When selecting a flange type, some important aspects include pressure capacity, pipe size, and intended application.
Common flange types include:
AWWA flanges are primarily used in waterworks applications and cover larger size ranges (up to 144″ in diameter) but lower pressure ratings.
ANSI/ASME B16.5 flanges are designed for industrial systems with higher pressure requirements and cover smaller diameters (up to 24″ in diameter).
ANSI / ASME B16.47 flanges cover the remaining sizes from 26″-60″ in diameter.
Pressure classes are defined in AWWA as B, D, E, and F for carbon steel and as SA, SB, SD, SE, and SF for stainless steel. In ANSI/ASME pressure classes, the pressure classes are defined as 150, 300, 400, 600, 900, 1500, and 2500.
ASME / ANSI Class 150 and Class 300 are pressure classes that indicate the flange’s allowable pressure capability at a given temperature. In general, Class 300 is rated for higher pressure service than Class 150, and it typically has heavier dimensions (thicker flange, different drilling by size) to support that duty.
To order industrial flanges from API International, share your pipe size, the flange standard and class you need (for example, ANSI/ASME B16.5, AWWA C207, or DIN EN 1092 PN), your facing requirement, and the material or coating requirements. If your project has special requirements like corrosion resistance, high temperature service, sour service, or specific bolt hole drilling, include that as well. Contact API International’s experienced team and we will help you select the right flange for your application from our massive stock inventory or custom machine it.
Not every weld neck flange looks identical. The tapered hub and butt-weld end are constant, but the face type, hub length, and bore can all change to fit a specific joint or industry requirement. This guide covers the main types
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