The product family ‘Branch fittings’ is somewhat surrounded by mystery. We often receive questions or incomplete enquiries because it’s not quite clear what to mention when it comes to types, dimensions, classes and range. In this blog we would like to provide some clarity around this theme.
Branch fittings are fittings which provide an outlet from one pipe to a larger one. This forged fitting, also known as ‘branch connection’ or ‘pipe branch outlet’ is welded on the main pipe which is usually called the run- or header pipe. The branch or outlet pipe is the pipe to which the branch connection provides a channel. A run pipe with a branch connection is weakened by the opening made in it. The branch connection is used to reinforce the opening and restore the original strength of the run pipe.
The most popular type of all branch connections is the one which is designed for welding onto the outlet pipe. Both ends are beveled, for a 90-degrees reinforced buttweld connection.
The Socket weld and Threaded version utilizes the basic buttweld-model, where the major difference is that the branch affixes by way of a socket weld / threaded connection. Besides these types, there are types with outlets as 45 degrees, elbows, inserts, nipples and more. The product details such as dimensions, finish, testing and tolerances are covered in the specification: MSS-SP 97. (Manufacturers Standardization Society – Standard Practice – no. 97)
Advantages of branch fittings
Using a branch fitting instead of a welding Tee allows more flexible fabrication with less use of space, because it can be welded on every possible spot, after running the pipe. The design – more specific, the funneled inlet- assures full fluid flow. The wide footing improves mechanical strength, and the short height makes it easy to inspect the inside of the pipeline.
Besides the advantages in usability there are clear cost benefits over conventional pipe branching techniques because only 2 welds are needed instead of 3.
To be able to fit the run side of the branch fitting on all kind of pipe diameters, without adjustments onsite, a variation in range is required. The standard (MSS SP-97) allows a maximum crotch or skirt gap of 1.6mm, as you can see in the image hereunder.
For example: our 2” (pipe size) branch fittings are available from stock in 3 variants with a run size 2 ½-3”/ 3 ½”-6”/ 8”-80”. These run sizes match the contour radius of the fitting to the run pipe radius without exceeding the required skirt and crotch gaps.
Arcus provides a wide range of branch fittings in all sizes, types, bores, and classes, in a variety of (stainless) steel, chrome-moly, and other alloys. The common types are available from stock in grades F304/L and F316/L with European origin, and meet the 2009 edition of MSS-SP-97 Standard- “Integrally Reinforced Forged Branch Outlet Fittings”.
How to specify an enquiry or order
– Outlet size
– Run size
– (Butt-weld / socket-weld / Threaded)
4: Class / Schedule:
– 3000 / 6000 LBS
– STD / XS
(Generally the schedules of the run pipe and branch pipe are identical. Where the schedule of the run is greater or less than the schedule of the branch, it is essential that both schedules be specified.)
5: Material grade.
6: Design code (if available).
Example: 10 pieces 6”x 1 ½” Weldolet STD F316L acc. MSS-SP-97