Pressure class rating of Flanges.

[aceface11]

Following Design conditions...

20 bar and 400?C
30 bar and 300?C

What would be the class rating required to do the job?

 

[C2it]

Depends on the material. Check the charts in ASME B16.5.

 

[1gibson]

Or B16.47 for over flanges 24"

 

[ione]

300lb for steel flange as per ASME B 16.5.

http://www.gowelding.com/pv/flange.htm

 

[enlight123]

The class rating shall be 300# as per ASME 16.5. For size above 24" Refer ASME 16.47. Hope this helps.

 

[JLSeagull]

Flanges exclude the # symbol ASME B16.5. Different pressure and temperature tables apply to different metals. Materials in groups 1.1 (A 105 or A 216 WCB CS) and 1.2 (A 350 and A216 WCC) will be high compared to others. I notice that I lack the 2009 standard on my home PC. Still, chrome moly, stainless steels are lower. I peaked at N08810 in the 2004 version.

Checking for 20 bar 400 deg C and 30 bar 300 deg C indicates that Class 150 is out above 15.9 bar at ambient. Class 300 is good for 30.7 bar at 300 deg C and 28.3 bar at 400 deg C. Most groups accomodate 30 bar at 400 degree C. Exclude B 564 Gr N08810. Some materials are not rated 400 deg C at any pressure like A 351 Gr. CN7M; N08700. A bad example is B 160 Gr. N02201 requiring Class 600 with foo deg C and 30.4 bar. Class 600 is required for A351 Gr CK20, CH8, CH20, .... But wait. Type 316L & type 304L are only rated 24.3 bar at 400 deg C in Class 300. F316, F316H, F317 Cl 600 above 28.4 deg C; F304, F304H etc. require Class 600 above 29.4 bar. Is carbon steel OK? Not A 350 Gr. LF1 Ci. 1 rated 29.3 on table 2-1.4.

Again, this data is out of date. Check the material but many materials permit nearly 30 bar at 400 deg C. Use the current code cause this just ain't right by current ASME B16.5. Over NPS 24? I ain't gonna look. Regards. ;-)

 

[JLSeagull]

BTW most are OK at 20 bar and 400?C and 30 bar and 300?C. Some exceptions exist.

 

[JLSeagull]

Class 300

 

[gr2vessels]

aceface, hello! Are the answers ok? Please be polite and thank the posters.