Weldolets, sockolets, threadolets, elbolets, latrolets and nipoflanges to MSS SP-97 for reinforced branch connections without cutting the main line.
- Standard: MSS SP-97, ASME B31.3, ASTM A105, ASTM A182, ASTM A350
- Grades: A105, A350 LF2, F304, F304L, F316, F316L, F11, F22, F91
Specifications
| Outer diameter | Run 1/2" - 48", branch 1/8" - 24" |
|---|---|
| Schedule | Matching run pipe schedule, SCH 10 - XXS |
| Length | Per MSS SP-97 for each type and size |
| Ends | Butt weld, socket weld, or threaded |
| Surface treatment | Black, galvanized, or machined |
| Manufacturing process | Forged and machined |
| Pressure rating | Per run pipe schedule and MSS SP-97 rating |
| Connection type | Weld on, socket weld, or threaded |
The Olet Family
An olet is a forged fitting welded onto the outside of a run pipe to create a reinforced branch. The weldolet is the basic type, used for a butt welded branch, and its tapered body acts as a reinforcement pad that restores the strength lost by the opening in the run pipe. The sockolet has a socket for a socket welded branch and is used for small bore connections. The threadolet has a threaded opening for a screwed branch. The elbolet fits on the back of an elbow, allowing a branch to be taken off at 90 degrees in a confined space. The latrolet makes a 45 degree branch. The nipoflange combines an olet with a flange, so a flanged branch can be made without a separate flange. All types are covered by MSS SP-97, which for a given run pipe size and branch size specifies the dimensions and the pressure rating. Selection is driven by the branch size, the branch connection type, and the required strength.
Olet versus Tee
Choosing between an olet and a tee comes down to how the branch will be made and how much strength is needed. An olet requires only one weld and does not cut the run pipe, so it avoids the cost and schedule of cutting a section out and welding a tee in, and it is generally the more economical choice for a small branch off a large header. A tee requires two girth welds but produces a fully integral branch of the same material and wall as the run, with a smooth bore and no internal projection. Where the branch is close to the run size, where pigging or flow requires an unobstructed bore, or where the highest level of integrity is required, a tee is the correct choice. Olets can also be difficult to use where the header is heavily corroded or where the wall thickness is unknown, because the olet geometry assumes a defined run wall thickness.
What is the difference between a weldolet and a sockolet?
A weldolet has a bevelled end for a butt welded branch and is used where the branch is welded directly to the olet with a full penetration weld, normally for larger branches or higher pressure. A sockolet has a socket recess, so the branch pipe inserts into it and is fillet welded, exactly like a socket weld fitting, and is used for small bore branches. Both are covered by MSS SP-97 and both are welded to the outside of the run pipe.
Can an olet be used on an existing line?
It can, and this is one of the main advantages of an olet over a tee, because the run pipe is not cut, so the line can often remain in service or be shut down for a shorter period. Two conditions must be met: the run pipe wall thickness must be known and adequate, since the olet is welded onto that wall and relies on it for reinforcement, and a hot tap procedure may be needed if the line cannot be depressurized. Confirm the run pipe grade, wall thickness and current condition before selecting the olet.
Materials
- Forged carbon steel
- Forged alloy steel
- Forged stainless steel
Typical applications
- Branch connections on headers and manifolds
- Instrument and drain connections
- Small bore tie-ins on large lines
- Retrofit branches on existing piping
- High pressure branch reinforcement
Inspection & testing
- Dimensional inspection per MSS SP-97
- PMI on alloy and stainless steel
- Hardness testing
- Chemical and mechanical testing per ASTM
- Third-party inspection on request
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