Branch Connections / IWO
Insert Weldolet
Weldolet with a partial insert into the run pipe for better alignment and flow transition.
Technical Specifications
Key Features
- Insert profile
- Improved alignment
- Better flow transition
- Reinforced body
- Weld compatible
- Type-tested
Applications
- Medium–high pressure lines
- Sensitive flow services
- Process equipment
- Petrochemicals
- Power sector
- General piping
Design Features
- Insert lip geometry
- Sealing compatibility
- Low misalignment tolerance
- Balanced load transfer
- High reliability
- NDT compatible
Connection Performance
Dimension Table
| Branch Size | Run Size | Outside Diameter (mm) | Insert Depth (mm) | Wall Thickness (mm) | Weight (kg) |
|---|---|---|---|---|---|
| 1/2" | 2" | 21.3 | 4.0 | 3.7 | 0.20 |
| 1" | 4" | 33.4 | 5.0 | 4.3 | 0.38 |
| 2" | 6" | 60.3 | 6.5 | 5.5 | 0.92 |
| 3" | 8" | 88.9 | 7.5 | 6.5 | 1.85 |
| 4" | 10" | 114.3 | 8.5 | 7.1 | 3.10 |
| 6" | 12" | 168.3 | 10.0 | 8.6 | 6.50 |
Technical Notes
- 01Control insert depth.
- 02Match run pipe wall thickness.
- 03Weld quality is critical.
- 04Radiographic testing recommended.
What are branch connection (olet) fittings?
Olet-type branch connection fittings are forged components that create a reinforced branch outlet from a run pipe without using a tee. Made to MSS SP-97, the most common types are the weldolet (butt-weld), sockolet (socket-weld) and threadolet (threaded). They are used from 1/2" to 24" under the ASME B31.1/B31.3 piping codes.
Olet types: weldolet, sockolet, threadolet, latrolet, elbolet
An olet body is integrally reinforced: its own wall section compensates the opening cut into the run pipe, so no reinforcing pad is needed. The type follows the branch pipe connection: the weldolet takes butt-welded larger branches; the sockolet (socket-weld) and threadolet (threaded) serve small branches, typically below 2". The latrolet makes a 45° lateral branch and the elbolet takes a branch off an elbow. For branches much smaller than the run — say a 1" outlet on an 8" line — an olet is faster and more economical than a reducing tee: the run stays uncut and one weld gives a reinforced outlet. Materials: forged carbon steel A105N, A350 LF2 for low temperature, A182 F304/F316 for stainless. Delivered with 3.1 certificates.
Frequently Asked Questions
Weldolet vs sockolet vs threadolet — what is the difference?+
The branch pipe connection: a weldolet is butt-welded (larger branches); a sockolet is socket-welded and a threadolet threaded (both typically for branches below 2").
When is an olet preferred over a reducing tee?+
When the branch is much smaller than the run (e.g. a 1" outlet on an 8" line): the run pipe stays uncut and a single weld gives a reinforced outlet, whereas a tee needs two run welds.
What are elbolets and latrolets for?+
A latrolet takes a 45° lateral branch off the run; an elbolet sits on the back of an elbow, usually for drain, vent or instrument connections.
Which standards cover olet fittings?+
Dimensions per MSS SP-97; branch end details per ASME B16.11 (socket/threaded) or B16.25 (weld bevel); system design follows the ASME B31.1/B31.3 piping codes.
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