Branch Connections / THD
Threadolet - Threaded Outlet
Threaded outlet enabling quick installation without welding.
Technical Specifications
Key Features
- Threaded (NPT/BSPT)
- No welding required
- Quick installation
- Compact design
- Easy maintenance
- Economical
Applications
- Low-pressure systems
- Temporary piping
- Maintenance taps
- Instrumentation
- Small lines
- Plumbing
Design Features
- NPT or BSPT thread
- Reinforced body
- Compact and lightweight
- Ease of assembly
- High strength
- Test-certified
Connection Performance
Dimension Table
| Branch Size | Run Size | Outside Diameter (mm) | Thread Length (mm) | Wall Thickness (mm) | Weight (kg) |
|---|---|---|---|---|---|
| 1/8"NPT | 1" | 10.3 | 6.4 | 2.8 | 0.03 |
| 1/4"NPT | 1-1/2" | 13.7 | 8.7 | 3.4 | 0.06 |
| 1/2"NPT | 2" | 21.3 | 10.2 | 3.7 | 0.11 |
| 3/4"NPT | 3" | 26.7 | 11.1 | 4.0 | 0.17 |
| 1"NPT | 4" | 33.4 | 12.7 | 4.3 | 0.24 |
| 1-1/2"NPT | 6" | 48.3 | 14.3 | 5.1 | 0.42 |
Technical Notes
- 01Use proper thread sealant.
- 02Thread quality inspection is key.
- 03Beware in vibrating environments.
- 04Periodic re-tightening may be needed.
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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