Weights and Dimensions
Which standard governs which number, and where to find the live tables.
Chrome-moly flange dimensions come straight from the ASME standards. The grade changes the rating and the fabrication requirements, not the geometry.
Outside diameter, thickness, bolt circle, hole count and hole size, and hub geometry all come from ASME B16.5 through NPS 24, or ASME B16.47 Series A or B from NPS 26 up. An F22 Class 300 weld neck is dimensionally identical to an A105 Class 300 weld neck. They interchange mechanically.
What changes is the pressure-temperature rating. ASME B16.5 assigns materials to groups, and the chrome-moly grades sit in different groups from carbon steel. At ambient temperature the ratings are similar. As temperature climbs, the chrome-moly grades hold their rating far better, and that divergence is the entire reason these grades exist. Read the rating from the table row for the actual material group, not from the carbon steel row.
Two further points that are specific to these grades. First, the class designation on F11, F12 and F22 refers to the heat treatment condition and strength level, not to the pressure class, so an F22 Class 3 forging in an ASME Class 300 flange is not a contradiction. Second, above roughly 800 degrees F the governing limit is often creep rather than the flange rating, and the design code takes over. Send us the design conditions and we will tell you whether the grade carries them.
The standards that matter
| Standard | Scope |
|---|---|
ASME B16.5 | Steel pipe flanges and flanged fittings, NPS 1/2 through 24 |
ASME B16.47 | Large diameter steel flanges, NPS 26 through 60, Series A and Series B |
ASME B16.20 | Metallic gaskets for pipe flanges, including ring joint, spiral wound and jacketed |
ASME B16.24 | Cast copper alloy pipe flanges and flanged fittings |
ASME B16.1 | Gray iron pipe flanges and flanged fittings |
AWWA C207 | Steel pipe flanges for waterworks service, Class B, D, E and F |
MSS SP-44 | Steel pipeline flanges, the origin of B16.47 Series A |
API 6A | Wellhead and christmas tree equipment, including 6B and 6BX ring groove flanges |
ASME B31.3 | Process piping. The design code that turns material allowables into a rating |
Pressure classes we supply
75, 125, 150, 175, 250, 300, 350, 400, 600, 900, 1500 and 2500, plus API 5K, 10K, 15K and 20K. High yield and low temperature grades are available across the range.
On weights
Published flange weights are nominal. They are calculated from the standard geometry at a nominal density and they do not account for machining allowance, the actual bore, the facing, or the specific gravity of the alloy you are ordering. For rigging, shipping and structural support, ask us for the calculated weight of the actual part rather than working from a table.
This matters more than it sounds at the large end. A flange that a table calls 900 pounds can land meaningfully off that once the real bore and facing are accounted for, and rigging plans do not like surprises.
This page is orientation, not a dimension table. Live dimensional tables for the ASME B16.5 and B16.47 patterns are maintained on the Texas Flange site. The governing document is always the current edition of the applicable standard. Confirm any dimension against the standard, or with us, before fabrication.
Texas Flange dimensional tables · Request a dimensioned drawing
Need the real weight or a verified dimension?
Send the print, or send the size, class and grade. Texas Flange quotes quickly.
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