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Conversion of Class flange and PSI flange, and comparison of pressure levels of common flanges
The most commonly used flange standards in the pipeline industry are the ANSI series, including ANSI B16.5, ANSI B16.47, AWWA C207 series, including BACKING FLANGE(BACK RING FLANGE), HUB FLANGE and AWWA C228 stainless steel series, EN1092-1 series, EN series. In addition to the four most common standards, there are JIS standards, BS standard,AS Australian standards, GOST Russian standards and South African standards.
In all these standards, forged flanges are classified according to their rated working pressure according to the designed pressure. Generally speaking, there are 7 levels: CLASS150, CLASS300, CLASS400, CLASS600, CLASS900, CLASS1500, CLASS2500. Normally, people would say "a 300-pound flange" instead of "a CLASS 300 flange". This is just a non-standard customary nomenclature. However, you must remember that a class 300 flange does not mean that the flange is rated at 300 psi. The formula is:
PT = Pr ST / 8750
PT = the rated working pressure of the specified material at temperature T, psi
Pr = pressure rating index
Allowable stress of flange material at temperature T, psi
According to experience, at ambient temperature, the maximum operating pressure of X-type carbon steel flanges is about 2.4 times. This rule is especially applicable to grades of 300 or higher. For example, at ambient temperature, the design pressure of a grade 300 carbon steel flange is 2.4 x 300 = 720 psi.
For the conversion of CLASS and PN, please check the technical webpage or blog, and please contact FLUIDO sale team or download the PDF of various flange standards from FLUIDO homepage www.eathu.com
ASME B16.5
| Class | Welding neck | Slip on | Socket welding | Threaded | Lapped joint | Blind |
| CL150(PN20) | 1/2"- 24" | 1/2"- 24" | 1/2"- 3" | 1/2"- 24" | 1/2"- 24" | 1/2"- 24" |
| CL300(PN50) | 1/2"- 24" | 1/2"- 24" | 1/2"- 3" | 1/2"- 24" | 1/2"- 24" | 1/2"- 24" |
| CL400 | 1/2"- 24" | 1/2"- 24" | 1/2"- 3" | 1/2"- 24" | 1/2"- 24" | 1/2"- 24" |
| CL600(PN110) | 1/2"- 24" | 1/2"- 24" | 1/2"- 3" | 1/2"- 24" | 1/2"- 24" | 1/2"- 24" |
| CL900(PN150) | 1/2"- 24" | 1/2"- 24" | 1/2"- 3" | 1/2"- 24" | 1/2"- 24" | 1/2"- 24" |
| CL1500(PN260) | 1/2"- 24" | 1/2"- 2-1/2" | 1/2"- 2-1/2" | 1/2"- 2-1/2" | 1/2"- 24" | 1/2"- 24" |
| CL2500(PN420) | 1/2"- 12" | - | - | 1/2"- 2-1/2" | 1/2"- 12" | 1/2"- 12" |
ASME B16.47 A (MSS SP-44)
| Class | Welding neck | Blind |
| 150 | 26"- 60" | 26"- 60" |
| 300 | 26"- 60" | 26"- 60" |
| 400 | 26"- 60" | 26"- 60" |
| 600 | 26"- 60" | 26"- 60" |
| 900 | 26"- 48" | 26"- 48" |
ASME B 16.47 B (API 605)
| Class | Welding neck | Blind |
| 75 | 26"- 60" | 26"- 60" |
| 150 | 26"- 60" | 26"- 60" |
| 300 | 26"- 60" | 26"- 60" |
| 400 | 26"- 36" | 26"- 36" |
| 600 | 26"- 36" | 26"- 36" |
| 900 | 26"- 36" | 26"- 36" |
AWWA C207
| Class | Steel-ring flanges | Steel-hub flanges |
| B (86psi) | 4"-144" (DN100-3600) | - |
| D (175-150psi) | 4"-144"(DN100-3600) | 4"-96" (DN100-2400) |
| E (275psi) | 4"-144" (DN100-3600) | 4"-96"( DN100-2400) |
| F (300psi) | 4"-48" (DN100-1200) | - |
EN1092.1
| PN | Plate (type01) | Slip on (type12) | Weld neck (type11) | Threaded (type13) | Blind (type05) |
| 2.5 | DN10-4000 | DN10-4000 | DN10-4000 | DN10-4000 | DN10-4000 |
| 6 | DN10-3600 | DN10-3600 | DN10-3600 | DN10-3600 | DN10-3600 |
| 10 | DN10-3000 | DN10-3000 | DN10-3000 | DN10-3000 | DN10-3000 |
| 16 | DN10-2000 | DN10-2000 | DN10-2000 | DN10-2000 | DN10-2000 |
| 25 | DN10-2000 | DN10-2000 | DN10-2000 | DN10-2000 | DN10-2000 |
| 40 | DN10-1600 | DN10-1600 | DN10-1600 | DN10-1600 | DN10-1600 |
| 63 | DN10-1200 | DN10-1200 | DN10-1200 | DN10-1200 | DN10-1200 |
| 100 | DN10-500 | DN10-500 | DN10-500 | DN10-500 | DN10-500 |
| 160 | - | - | DN10-300 | - | - |
| 250 | - | - | DN10-300 | - | - |
| 320 | - | - | DN10-250 | - | - |
| 400 | - | - | DN10-200 | - | - |
Please check FLUIDO flange product page for dimension, weight list and price list, if you can't find the information you need, please contact FLUIDO sale team.
