Dresser · Bolted Coupling
Style 138 Bolted Coupling for Cast and Ductile Iron Pipe
One coupling per nominal size, 3 in through 12 in, to fit cast iron of any vintage and modern ductile iron.
250 PSI Max Working Pressure
212°F Max (Grade 27 Gasket)
Grade 27 Buna-S Gasket
Carbon Steel Middle Ring and Followers
AWWA C111 Bolts, Black E-Coat
Fusion-Bonded Epoxy ID and OD
NSF/ANSI 61 and 372
3.74-13.56 in Pipe OD
15-65 lb Weight
Overview
Stock one Dresser Style 138 in each nominal size, 3 through 12 in, and be sure of a fit whether the cast iron pipe was made in 1890 or comes from your latest ductile iron shipment. Dresser builds the 138 so one middle ring can be used with up to four different gaskets and three followers to cover a wide range of pipe.
Application: Repair and joining on cast iron and ductile iron mains where the pipe class is unknown.
- Covers the OD range of a nominal size, cast iron of any age through ductile iron
- 250 PSI working pressure, every size
- Fusion-bonded epoxy ID and OD standard; RED-D shopcoat optional
- For 14 in and larger, Dresser uses the Style 38 for cast and ductile iron
NSF/ANSI 61 and 372 certified per Dresser’s 2024 Water Pipe Joining catalog. Only products bearing the NSF mark are certified.
What Ships and What It Needs to Run
Included: one middle ring, two followers, two Grade 27 gaskets, bolts and nuts.
Pipe prepared before install: plain pipe ends, clean and round where the gaskets seat.
Anchoring, by others: the coupling seals but does not restrain.
Genuine Dresser equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier.
12-Month Dresser Warranty
Covered for 12 months from the date of purchase under Dresser’s published warranty terms.
Working Pressure
250 PSI in every size, 3 through 12 in. The allowable pressure on a job also depends on the pipe, its condition and the workmanship.
Materials Specifications
| Followers |
AISI C1012 or ASME SA36 |
| Middle ring |
ASTM A513, ASTM A635 or ASME SA675 GR60 |
| Bolts and nuts |
AWWA C111 / ANSI A21.11, black E-coat |
| Gasket |
Grade 27 Buna-S standard; optional gaskets available |
| Coating |
Fusion-bonded epoxy ID and OD; RED-D shopcoat optional |
Source: Dresser Style 138 data sheet.
Sizes
| Nominal |
Pipe OD range (in) |
| 3 in |
3.74-4.02 |
| 4 in |
4.74-5.06 |
| 6 in |
6.84-7.16 |
| 8 in |
8.99-9.36 |
| 10 in |
11.04-11.46 |
| 12 in |
13.14-13.56 |
Dresser 2021 cast/ductile iron submittal. Middle ring length (5 or 7 in) and coating are picked in the options.
Installation Notes
- Clean dirt, rust, oil and loose scale from the pipe ends and check the gasket seat for gouges or grooves.
- On couplings, chalk-mark each pipe half the middle ring length plus 2 in back from the end to center the coupling.
- Slide the followers on, lubricate the gaskets, pipe OD and middle ring flares with soapy water or a non-petroleum lubricant, and seat the gaskets.
- Stab the pipe so each end sits at least 1 in past the gasket after deflection.
- Draw the nuts up finger tight, then tighten opposite sides evenly to the recommended torque; check every nut before backfilling.
Source: Dresser installation instructions for Styles 38, 40, 56, 62, 69, 71, 72, 76, 89, 128 and 168 (tag 0001-0737-999).
Before You Order. Measure the pipe OD with a pi tape and match it to the OD in the picker; cast and ductile iron run larger than steel of the same nominal size. Dresser builds couplings for odd ODs, other middle ring lengths, stainless steel and other gasket grades on request: email
sales@watermainsupply.com with the OD and the line content. Non-stock Dresser parts are not returnable without Dresser’s authorization, and ship time is confirmed when you order. Custom builds (other sizes, widths, gaskets or materials) are available: email
sales@watermainsupply.com with the pipe OD, material and line content.
