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Dresser Style 128 Flange Adapter
Description
Dresser Style 128 Flange Adapters
The Dresser Style 128 Flange Adapter mechanically transitions mechanical-joint or plain-end pipe to an AWWA Class D (and ANSI-compatible) flanged connection — without welding or threading. Available for cast and ductile iron pipe as well as steel pipe, from 4" through 36".
128
Style Number
4"–36"
Size Range
AWWA Cl. D
Flange Standard
2
Pipe Series (CI & Steel)
Product Lines
Cast/Ductile Iron & Steel Pipe Series
The Style 128 ships in two distinct bore configurations. Ordering the wrong pipe-series adapter is the most common Style 128 specification error.
128CI / DI Pipe
Style 128 — Cast & Ductile Iron
Bored to accept cast and ductile iron pipe OD. Covers 4" through 36" nominal. AWWA Class D flange face drilled for standard bolt circle. Fusion bonded epoxy or RED-D Shopcoat finish available.
128Steel Pipe
Style 128 — Steel Pipe
Bored to IPS steel pipe OD. Available 4" through 36" nominal. Same AWWA Class D flange drilling. Used extensively for pump station piping and process connections where the pipe is schedule carbon steel.
Standards Reference
AWWA Class D vs ANSI 150 — What's Compatible?
This is the question asked on every flange adapter order. The short answer: compatible in most water system sizes, but verify bolt circle and facing before assuming interchangeability.
| Size | AWWA Cl. D BC | ANSI 150 BC | Compatible? |
|---|---|---|---|
| 4" | 7.50" | 7.50" | ✔ Yes |
| 6" | 9.50" | 9.50" | ✔ Yes |
| 8" | 11.75" | 11.75" | ✔ Yes |
| 10" | 14.25" | 14.25" | ✔ Yes |
| 12" | 17.00" | 17.00" | ✔ Yes |
| 16" | 21.25" | 21.25" | ✔ Yes |
| 20" | 25.00" | 25.00" | ✔ Yes |
| 24" | 29.50" | 29.50" | ✔ Yes |
Facing Standard
AWWA Class D flanges use a raised-face or flat-face configuration depending on the mating equipment. Confirm whether your valve, pump, or meter has a raised-face or flat-face flange before ordering gaskets and specifying the Style 128 facing.
Pressure Class Mismatch
AWWA Class D is rated to 175 PSI for sizes through 12" and 150 PSI for larger sizes. If your system operates above 150 PSI on larger-diameter pipe, you may need ANSI Class 300 flanged connections instead of Class 150/AWWA Class D.
Pipe OD Reference
CI/DI OD vs Steel IPS OD — Key Sizing Data
The Style 128 gasket and sleeve must match the actual pipe OD — not the nominal size label. Use measured OD or the table below to specify correctly.
| Nominal | Steel IPS OD | Cast / Ductile Iron OD | Correct Style 128 Part Series |
|---|---|---|---|
| 4" | 4.500" | 4.74–5.16" | Steel: 0128-1850 / CI: 0128-1900 |
| 6" | 6.625" | 6.84–7.16" | Steel: 0128-1852 / CI: 0128-9902 |
| 8" | 8.625" | 8.99–9.36" | Steel: 0128-1854 / CI: 0128-1904 |
| 10" | 10.750" | 11.04–11.46" | Steel: 0128-9856 / CI: 0128-1906 |
| 12" | 12.750" | 13.14–13.56" | Steel: 0128-9858 / CI: 0128-1908 |
| 14" | 14.000" | 15.30" | Steel: 0128-8860 / CI: 0128-8910 |
| 16" | 16.000" | 17.40" | Steel: 0128-8862 / CI: 0128-8912 |
| 20" | 20.000" | 21.60" | Steel: 0128-8866 / CI: 0128-8916 |
| 24" | 24.000" | 25.80" | Steel: 0128-8868 / CI: 0128-8918 |
Installation Engineering
Bolt Torque and Gasket Requirements
A properly installed Style 128 flange adapter requires both a correctly torqued follower ring (the mechanical coupling side) and a separate full-face or ring gasket at the mating flange face.
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Follower Ring Torque
The coupling sleeve side is torqued per the Dresser torque chart for that pipe size and bolt diameter. This is a separate operation from bolting the mating flange together.
Follow Dresser Torque Table
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Flange Face Gasket
Install a full-face (for flat-face flanges) or ring-type (for raised-face flanges) gasket at the mating connection. The Style 128 does not include this gasket — order separately.
Not Included — Order Separately
⚖️
Thrust Restraint
The Style 128 is not inherently self-restrained. At high-pressure or large-diameter installations, verify that the mating valve or pump body provides restraint, or install external tie rods.
Verify Per Project Specs
Order Checklist
Four Pieces of Information Needed to Order
Have these four data points ready before contacting us and your order will ship without a clarification delay.
1
Pipe Material & OD
Is the pipe steel, cast iron, or ductile iron? Confirm the actual measured OD, not just the nominal size. This determines which bore series to order.
2
Nominal Pipe Size
Confirm nominal size to select the correct flange drilling (bolt circle, number of bolts, bolt diameter). Sizes 4" through 36" are available.
3
Mating Flange Standard
Is the mating equipment drilled to AWWA Class D, ANSI 150, or another standard? Confirm bolt circle and number of holes before assuming compatibility.
Ready to Order or Need Technical Help?
Contact our team for availability, custom sizing, and volume pricing on Dresser Utility Solutions products.
Email sales@watermainsupply.com Call 281.664.8000
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