Buttweld Fitting Dimensions — B16.9
Centre-to-end dimensions for elbows, tees, reducers and caps, NPS 1/2 through NPS 24. Because ASME B16.9 dimensions depend on nominal size alone, one table covers every schedule.
Fittings side by side
The governing dimension of each fitting at four common sizes.
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Fitting | NPS 2 | NPS 6 | NPS 12 | NPS 24 |
|---|---|---|---|---|
| 90° Long Radius Elbow | 3.0076.20 mm | 9.00228.60 mm | 18.00457.20 mm | 36.00914.40 mm |
| 90° Short Radius Elbow | 2.0050.80 mm | 6.00152.40 mm | 12.00304.80 mm | 24.00609.60 mm |
| 45° Long Radius Elbow | 1.3835.05 mm | 3.7595.25 mm | 7.50190.50 mm | 15.00381.00 mm |
| Straight Tee | 2.5063.50 mm | 5.62142.75 mm | 10.00254.00 mm | 17.00431.80 mm |
| Reducing Tee | 2.5063.50 mm | 5.62142.75 mm | 10.00254.00 mm | 17.00431.80 mm |
| Concentric Reducer | 3.0076.20 mm | 5.50139.70 mm | 8.00203.20 mm | 20.00508.00 mm |
| Eccentric Reducer | 3.0076.20 mm | 5.50139.70 mm | 8.00203.20 mm | 20.00508.00 mm |
| Cap | 1.5038.10 mm | 3.5088.90 mm | 6.00152.40 mm | 10.50266.70 mm |
Common questions
Do buttweld fitting dimensions depend on the pipe schedule?
No. ASME B16.9 fixes every centre-to-end dimension from NPS alone. Schedule changes the wall thickness and the bore, not the geometry, so a schedule 10 and a schedule 160 elbow of the same size occupy exactly the same space.
What is the difference between a long radius and short radius elbow?
The centreline bend radius. A long radius elbow bends on 1.5 × NPS, a short radius on 1.0 × NPS. Long radius is the default: it costs less pressure drop and erodes more slowly. Short radius is a space-saving compromise.
Which way up does an eccentric reducer go?
Flat side up on pump suction, so vapour cannot collect at the high point and cavitate the pump. Flat side down on horizontal runs that must drain, so liquid cannot pool. Getting this backwards is one of the more common piping errors.