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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.
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.
The American Water Works Association (AWWA) has issued a specification revision affecting the bolt hole diameter for 22″ Class-F flanges. This revision is applicable to Carbon Steel (AWWA C207 Class F) and Stainless Steel (AWWA C228 Class SF) materials, in
ASTM A105 forged carbon steel flanges are the industry standard for pressure-rated piping across process, power, and oil and gas applications. A105 grade delivers the grain structure and mechanical properties required for moderate and high-pressure service. This material is referenced
Threaded pipe flanges are widely used across industrial, commercial, and municipal piping systems. Selecting the right one for a specific application involves more than just choosing a pipe size. Before specifying or installing a threaded pipe flange, engineers and procurement
Selecting a carbon steel flange grade is one of the most important decisions in industrial piping procurement. The grade determines whether a flange can handle the system’s pressure, how it performs at operating temperature, and which dimensional standards it qualifies
Domestic ASTM A36 is one of the most commonly specified carbon steel grades in American manufacturing. The combination of low carbon content, reliable weldability, and domestic availability makes it a practical choice across a wide range of industrial applications, which
Carbon steel flanges are among the most widely used pipe connection components in industrial infrastructure. They are reliable, cost-effective, and available in a range of grades and configurations. They are also able to match nearly any service condition. This guide
Threaded companion flanges are widely used across industrial, commercial, and municipal piping systems. Selecting the right one for a specific application involves more than just choosing a pipe size. Before specifying or installing a threaded flange, engineers and procurement teams
On the surface, choosing between threaded and socket weld flanges can seem like a minor detail. In reality, the sealing performance difference between the two is meaningful. This guide breaks down how each connection works, where each performs well, where
Not every piping connection can be welded. In explosive atmospheres, remote locations, or systems requiring regular disassembly, threaded companion flanges provide an essential alternative. Standardized under ANSI/ASME B16.5 and used across oil & gas, process, and utility piping systems worldwide,
Plate flanges are cut or machined from flat steel plate rather than forged from bar or billet. They are widely used in waterworks, irrigation, selected industrial systems, utility connections, and other applications where ring-type slip-on and blind flange styles are
