Types of olets

• Weldolet – butt-weld branch outlet, bevelled to match the branch pipe schedule (STD, XS, Sch 160, XXS). The most common olet, for full-strength branches.
• Sockolet – socket weld outlet, Class 3000 or 6000, for small-bore branches.
• Threadolet – threaded outlet (NPT or BSP), Class 3000 or 6000, for instrument and vent connections.
• Elbolet – fits on a long-radius elbow, for thermowells and instruments at bends.
• Latrolet – makes a 45° lateral branch.
• Nipolet – a weldolet with an integral nipple, for valve and drain connections.
• Sweepolet – contoured, low-stress outlet with a smooth flow path, for high-pressure and cyclic service.

Branch sizing

An olet is described by two sizes: the branch size (the outlet) and the run size range it fits. Because the base is contoured to the curve of the run pipe, one olet design covers a range of run sizes – for example, a 1" weldolet may be made for runs of 3" to 36", or for a specific run size. The branch outlet is matched to the branch pipe schedule (weldolets) or class (sockolets and threadolets). The piping specification's branch table tells which fitting to use for each run and branch combination; olets are normally used where the branch is at least two sizes smaller than the run.

Olets are integrally reinforced, so no extra reinforcing pad is needed when the olet is selected correctly for the run and branch. Pipe dimensions are in the pipe schedule chart.

Specifications

Olet materials

• Stainless steel – ASTM A182 F304/304L, F316/316L, F321, F347.
• Carbon steel – ASTM A105, A350 LF2.
• Alloy steel – ASTM A182 F5, F9, F11, F22, F91.
• Duplex steel – ASTM A182 F51, F60.
• Super duplex – ASTM A182 F53, F55.
• Inconel – ASTM B564, and other nickel alloys.

All fitting materials are on the pipe fittings page.

How we manufacture olets

Olets are closed-die forged from bar of certified material, heat treated as the material specification requires, and machined: the base is contoured to the run pipe, the outlet is bevelled, socketed or threaded, and the bore is finished. Each olet is marked with material, branch size, run size range, schedule or class and heat number.

Installation

The run pipe is cut with a hole matching the olet bore, the olet is set over it and welded with a full-penetration weld around the contoured base. Weld size and inspection follow the piping code. The branch pipe is then butt welded, socket welded or screwed to the outlet.

Ordering olets

Please give the olet type, material, branch size, run size, branch schedule or class, end connection, quantity and any testing or inspection requirement.