Buttweld Fittings

Written by Matt Milbury on . Posted in Pipe Fittings

Buttweld fittings can be split up into different categories depending on what it's function is.  These categories are:

  • Elbows are used whenever there is a direction change required
  • Branch Connections are used when a piece of pipe or tubing is joining to another piece of pipe or tubing. 
  • Reducers are used when the nominal diameter of the pipe changes.
  • Caps are used when the pipe run ends.

All the datasheets that are linked below can be found on our Buttweld Fitting Datasheet page.  Each datasheet contains a drawing & photo of the component as well as dimensional data. 

Elbows

45 Elbow Long Radius

A 45 degree elbow "long radius"  (abbreviated as 45 ELB LR) has a centerline curvature equal to 1-1/2 times the nominal pipe size (NPS) for 3/4 inch and larger sizes.

View the 45 Elbow Long Radius Datasheet

45 Elbow Long Radius Long Tangent

A 45 degree elbow "long radius, long tangent" (abbreviated as 45 ELB LR LT)is a long radius with the centerline curvature equal to 1-1/2 times the nominal pipe size (NPS) and a straight extension at both ends (long tangent) for 2 inch and larger sizes. Tangent elbows provide a straight length at the end to accept a Slip-on Flange. The tangent end for the flange is not beveled.

View the 45 Elbow Long Radius Long Tangent Datasheet

45 Elbow Three Radius

A 45 degree elbow "three radius" (abbreviated as 45 ELB 3R) is a long radius elbow with the centerline curvature equal to 3 times the nominal pipe size (NPS).

View the 45 Elbow Three Radius Datasheet

Three Radius ElbowThree Radius Elbow90 Elbow Long Radius

A 90 degree elbow "long radius" (abbreviated as 90 ELB LR) has a centerline curvature equal to 1-1/2 times the nominal pipe size (NPS) for 3/4 inch and larger sizes.

View the 90 Elbow Long Radius Datasheet

90 Elbow Long Radius Long Tangent

A 90 degree elbow "long radius, long tangent" (abbreviated as 90 ELB LR LT) is a long radius with the centerline curvature equal to 1-1/2 times the nominal pipe size (NPS) and a straight extension at both ends (long tangent) for 2 inch and larger sizes. Tangent elbows provide a straight length at the end to accept a Slip-on Flange. The tangent end for the flange is not beveled.

View the 90 Elbow Long Radius Long Tangent Datasheet

90 Elbow Short Radius

A 90 degree elbow "short radius" (abbreviated as 90 ELB SR) has a centerline curvature equal to 1 times the nominal pipe size (NPS) for 1 inch and larger sizes.

View the 90 Elbow Short Radius Datasheet

90 Elbow Short Radius Long Tangent

A 90 degree elbow "short radius, long tangent" (abbreviated as 90 ELB SR LT) is a short radius with the centerline curvature equal to 1 times the nominal pipe size (NPS) and a straight extension at both ends (long tangent) for 8 inch and larger sizes. Tangent elbows provide a straight length at the end to accept a Slip-on Flange. The tangent end for the flange is not beveled.

90 Elbow Three Radius

A 90 degree elbow "three radius" (abbreviated as 90 ELB 3R) is a long radius with the centerline curvature equal to 3 times the nominal pipe size (NPS).

View the 90 Elbow Three Radius Datasheet.

180 Return Long Radius

A 180 degree return "long radius" (abbreviated as 180 RTN LR) has a centerline curvature equal to 1-1/2 times the nominal pipe size (NPS) for 3/4 inch and larger sizes.

View the 180 Return Long Radius Datasheet

180 Return Short Radius

A 180 degree return "short radius" (abbreviated as 180 RTN SR) has a centerline curvature equal to 1 times the nominal pipe size (NPS) for 1 inch and larger sizes.

View the 180 Return Short Radius Datasheet

Mitered Elbow

A mitered elbow (abbreviated as MIT ELB) is fabricated from pipe and is not a fitting. A miter is used for larger pipes, where pressure drop is not important and cost is a factor. A 2 piece 90 degree miter has 4 to 6 times hydraulic resistance of the corresponding long radius elbow. A 3 piece, 90 degree miter has about double the resistance. The normal number of miter pieces used are 3, 4, or 5.

Bend

A bend is made from a straight piece of pipe. The most common bends are 3 or 5 times the nominal pipe size (NPS) radius.

Branch Connections

Straight Tee

A straight tee (abbreviated as STR TEE) has the same branch size as the pipe. These are used for making 90 degree branching from the main run of pipe.

View the Straight Tee Datasheet

Straight Cross

A straight cross (abbreviated as STR CROSS) has the same branch size as the pipe. These are used for making 90 degree branching from the main run of pipe.

View the Straight Cross Datasheet

Reducing Tee

Reducing tees (abbreviated as REDC TEE) have a single 90 degree branch from the main run of pipe. The branch is smaller than the main run.

View the Reducing Tee Datasheet

Reducing Cross

Reducing crosses (abbreviated as REDC CROSS)have two 90 degree branches from the main run of pipe. The branch is smaller than the main run.

View the Reducing Cross Datasheet

Saddle

A saddle (abbreviated as SDL) or tapping saddle is used when you do not want to shut down a pipeline, but want to add a branch. This allows a branch to be added for hot tapping an existing system. Saddles come in both full and reducing branches.

View the Buttweld Saddle Datasheet

Reinforcing Saddle

These saddles (abbreviated as REINF SDL)are split in two pieces that fully encircle the branch connection. They come in two types. One slides over the branch and the other fits around the branch. The saddle is split along the length of the pipe. Reinforcing saddles come both in full and reducing branches.

View the Reinforcing Saddle Datasheet

Split Tee

Vertical Split TeeVertical Split TeeHorizontal Split TeeHorizontal Split TeeSplit Tee with cutoutSplit Tee with cutout

 

Stub-in

It is the term for a branch of pipe welded directly into the side of a main pipe run. It is not a fitting. This is the most common and least expensive method of welding a full size or reducing branch for pipe. A stub in can be reinforced. It is very important to verify the stub in connection against whatever applicable piping code you are designing to.  For example, B31.3 allows for stub in connections only if calculations are performed to ensure the connection is strong enough to withstand whatever forces are expected on the weld.

Reducers

Concentric Reducer

The concentric reducer (abbreviated as CONC RDCR) centerline of the inlet and outlet is at the same level. Eccentric Reducer Flat on BottomEccentric Reducer Flat on Bottom

Eccentric Reducer

The eccentric reducer (abbreviated as ECC RDCR) offset is equals 1/2 times the larger ID minus the smaller ID.

 

The eccentric reducer is used to keep either the top or bottom of the pipe level. It is used with the flat side up (flat on top FOT) or flat side down (flat on bottom FOB). In wet gas such as casing gas applications, an eccentric reducer should be used that is flat on bottom to prevent condensing liquids from pocketing.

 

It is common practice to install eccentric reducers on a liquid line that might have a little gas in it with the flat side of the reducer is put on the top. That ensures that any bubbles that come along the top pass immediately through the pump and not accumulate. If they accumulate, they may collect and enter the pump in bulk causing it to intermittently cavitate.

Both Concentric and Eccentric Reducers are on the same datasheet.  View it here.

Swage - There are three types - concentric (CONC SWG), eccentric (ECC SWG) and ventury. A swage is used to connect buttwelded and screwed fittings/pipe to smaller or larger buttweld or screwed fittings/pipe.

  • "Concentric" swage centerline of the inlet and outlet is at the same level.

  • "Eccentric" swage is offset either on the top or bottom of the line level.

  • "Venturi" swage creates a smooth flow.

Caps

Dished Head Cap

These have a straight tangent with a rounded head.

View the Dished Head Cap Datasheet

Flat Closure Cap

These are flat plates normally cut for pipe at the site.

Companies

Standards

ASME Standards

  • ASME B16.9 - Factory-Made Wrought Buttwelding Fittings