Specifications & Dimensions
Pressure ratings, dimensional data, and bolt patterns for lightweight steel pipe flanges.
AWWA C207 Classes
Working pressure limits at ambient temperature per AWWA C207. Class selection depends on system operating pressure and the required safety margin.
| Class | Working Pressure | Size Range | Face Type | Application |
|---|---|---|---|---|
| Class B | 86 psi | 4" - 144" | Flat Face | Low-pressure distribution, gravity flow |
| Class D | 175 psi (≤12") / 150 psi (>12") | 4" - 144" | Flat Face | Standard waterworks, moderate pressure |
| Class E | 275 psi | 4" - 144" | Flat Face / Raised Face | Transmission mains, pump discharge |
| Class F | 300 psi | 4" - 144" | Flat Face / Raised Face | High-pressure industrial, process piping |
Class 125LW Slip-On Flange Dimensions
Outside diameter, thickness, bolt circle, and bolt hole data for standard Class 125LW slip-on flanges. Bolt pattern matches ANSI B16.1 Class 125 cast iron.
| NPS | OD (in) | Thickness (in) | Bolt Circle (in) | No. Bolts | Bolt Dia (in) | Approx Wt (lbs) |
|---|---|---|---|---|---|---|
| 4 | 9.00 | 0.56 | 7.50 | 8 | 0.75 | 7 |
| 6 | 11.00 | 0.62 | 9.50 | 8 | 0.75 | 10 |
| 8 | 13.50 | 0.69 | 11.75 | 8 | 0.75 | 15 |
| 10 | 16.00 | 0.75 | 14.25 | 12 | 0.88 | 22 |
| 12 | 19.00 | 0.81 | 17.00 | 12 | 0.88 | 32 |
| 14 | 21.00 | 0.88 | 18.75 | 12 | 1.00 | 40 |
| 16 | 23.50 | 0.94 | 21.25 | 16 | 1.00 | 52 |
| 18 | 25.00 | 1.00 | 22.75 | 16 | 1.13 | 62 |
| 20 | 27.50 | 1.06 | 25.00 | 20 | 1.13 | 78 |
| 24 | 32.00 | 1.19 | 29.50 | 20 | 1.38 | 110 |
| 30 | 38.75 | 1.31 | 36.00 | 28 | 1.38 | 165 |
| 36 | 46.00 | 1.44 | 42.75 | 32 | 1.63 | 250 |
| 42 | 53.00 | 1.56 | 49.50 | 36 | 1.63 | 340 |
| 48 | 59.50 | 1.69 | 56.00 | 44 | 1.63 | 450 |
| 54 | 66.25 | 1.81 | 62.75 | 44 | 1.88 | 575 |
| 60 | 73.00 | 1.94 | 69.25 | 52 | 1.88 | 720 |
| 72 | 86.50 | 2.19 | 82.50 | 60 | 2.13 | 1080 |
| 84 | 100.00 | 2.44 | 95.50 | 64 | 2.38 | 1520 |
| 96 | 113.25 | 2.69 | 108.50 | 68 | 2.44 | 2040 |
Dimensions are nominal. Actual measurements may vary within AWWA C207 tolerances. Contact engineering for sizes above 96".
96" Class 125LW Flange Drawing
Example engineering drawing showing plan view, 3D rendering, and cross-section with full dimensional callouts.
96" NOM - 125LW-FF-SO-FLANGE
68x 2.438" bolt holes on 108.5" bolt circle. 113.25" OD, 3.25" thick.
Class 125LW Cross-Section
Standard dimensional variables: A (OD), B (bore), C (bolt circle), E (hub dia), T (thickness).
AWWA C207 Material Specification
Minimum material properties required per AWWA C207 for steel plate, bar, or forging stock used in flange manufacture.
50,000 psi
Minimum tensile strength
32,000 psi
Minimum yield strength
18%
Min. elongation (2" gauge)
0.35%
Maximum carbon content
0.04%
Maximum phosphorus
0.05%
Maximum sulfur
Bolt & Gasket Specifications
Bolting
Standard bolting per AWWA C207: studs conforming to ASTM A193 Grade B7 with heavy hex nuts per ASTM A194 Grade 2H. For bolt sizes 1" and smaller, ASTM A563 heavy hex nuts are acceptable.
Bolt length must account for flange thickness, gasket compression, nut height, and sufficient thread engagement. Consult our engineering team for bolt length calculations on non-standard assemblies.
Gaskets
Gasket selection depends on face type, media, temperature, and pressure. Common gasket materials for lightweight flange service include full-face rubber (EPDM, Neoprene, Nitrile), compressed fiber (non-asbestos), and PTFE for chemical resistance.
Full-face gaskets are required when mating with flat-face cast iron flanges per ASME guidelines. Ring gaskets may be used between two raised-face steel flanges.