Differences between ASME B16.5 and BS4504 flanges
Flanges play a crucial role in piping systems, ensuring secure connections between pipes, valves, and other equipment. Two widely used flange standards are ASME B16.5 and BS4504, each catering to different industries and regions. Understanding their differences is essential when selecting the appropriate flange for a project.
ASME B16.5 A105 RF slip on flanges
1.Source and scope of application of standards
Source: Developed by the American Society of Mechanical Engineers (ASME), widely used in the North American market.
Scope of application: Applicable to pipe flanges and flange accessories with nominal size (NPS) 1/2″ to 24″, and pressure levels from Class 150 to Class 2500.
Applicable materials: Covering carbon steel, stainless steel, alloy steel, nickel-based alloys, etc., the materials must comply with relevant ASME standards (such as ASTM A105, A182, A350, etc.).
BS4504:
Source: British Standard (BS), mainly used in Europe and Commonwealth countries.
Scope of application: Applicable to flanges with nominal diameter (DN) 10 to DN 4000, and pressure levels of PN 2.5 to PN 40.
Applicable materials: Carbon steel and stainless steel are usually used, in accordance with EN 1092-1 or BS EN standards.
Galvanized BS4504 plate flanges
2.Pressure Rating of Flanges
ASME B16.5 uses Class 150, Class 300, Class 600, Class 900, Class 1500 and Class 2500.
These grades are based on pressure-temperature ratings, and the maximum allowable pressure decreases as the temperature increases.
BS4504 uses PN (pressure nominal value) notation, and common grades include PN 2.5, PN 6, PN 10, PN 16, PN 25 and PN 40, and the unit is bar (1 bar ≈ 14.5 psi).
Comparison:
Class 150 of ASME B16.5 is roughly equivalent to PN 20 of BS4504, but they are not directly equivalent because their design bases are different.
3.Flange size and bolt hole arrangement
ASME B16.5: Flange size, bolt hole location, number, bolt size, etc. are all based on inches, and the flange face-to-face size is fixed.
BS4504: Flange size is in millimeters (mm), and the bolt hole arrangement may be different from the ASME flange, usually with a larger bolt hole spacing than the ASME flange.
Comparison:
The bolt holes of ASME flanges and BS4504 flanges are not necessarily compatible and cannot be directly interchanged unless specially adapted.
ASME B16.5 is applicable to ANSI-level piping systems, and BS4504 is applicable to European standard piping systems.
While both ASME B16.5 and BS4504 are important flange standards, they serve different industries and geographical regions. ASME B16.5 is best suited for high-pressure industrial applications, whereas BS4504 is more commonly used in municipal and general-purpose piping systems. Understanding their differences in pressure ratings, dimensions, and applications is essential for selecting the right flange for any project. Email:sales@haihaogroup.com