Weights and Dimensions | Ring Flanges

Ring flange dimensions come from several unrelated standards, and the fastest way to get a part wrong is to read one flange against another standard table.

AWWA C207 governs the waterworks ring and hub flanges, Class B, D, E and F. ASME B16.5 governs steel pipe flanges through NPS 24, including the ring type joint facings. ASME B16.47 Series A and B cover the large diameter patterns from NPS 26 up. ASME B16.20 covers the ring joint gaskets themselves, and API 6A and 6BX cover the wellhead ring grooves.

These do not interchange. An AWWA C207 Class D ring flange and an ASME B16.5 Class 150 flange share a bolt template in many sizes, which is genuinely useful and also the source of most of the confusion, because sharing a bolt circle does not mean sharing a rating or a thickness. B16.47 Series A and Series B do not bolt to each other at all, despite carrying the same class designation.

Ring joint facing is also not available across the whole class range. Under ASME B16.5 the RTJ facing starts above Class 150, and on B16.47 Series A it is defined over part of the class range rather than all of it. Confirm against the current edition before you specify one.

Dimensioned drawing of a 24 inch AWWA C207 Class D ring flange showing 32 inch outside diameter, 29.5 inch bolt circle, twenty 1.375 inch holes and 1.25 inch thickness — Dimensional geometry is defined by the standard. The rating is defined by the material and the design code. Keep the two separate.

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 AWWA, 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

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