Reducer Fittings Catalog - ASME B16.9
Optimized reduction components and technical solutions for pipe diameter transitions
Reducer Types
ASME B16.9 Standard
Concentric Reducer
Axially aligned, symmetrical flow transition fitting for standard pipe reduction.
Reduction Ratios:
ASME B16.9 Standard Dimensions
| Nominal Size | Large OD (mm) | Small OD (mm) | Thickness (mm) | Length (mm) |
|---|---|---|---|---|
| 1" x 1/2" | 33.4 | 21.3 | 3.38 | 51 |
| 2" x 1" | 60.3 | 33.4 | 3.91 | 64 |
| 4" x 2" | 114.3 | 60.3 | 6.02 | 76 |
| 6" x 4" | 168.3 | 114.3 | 7.11 | 89 |
| 8" x 6" | 219.1 | 168.3 | 8.18 | 102 |
| 12" x 8" | 323.9 | 219.1 | 10.31 | 152 |
| 16" x 12" | 406.4 | 323.9 | 12.70 | 203 |
Main Features
- Axial alignment
- Low flow resistance
- Even pressure distribution
- Easy installation
- Standard dimensions
- High efficiency
Application Areas
- Vertical pipelines
- Pump outlets
- Tank connections
- General piping
- HVAC systems
- Water lines
Flow Characteristics
Design Features
- Symmetrical conical design
- Smooth internal surface
- Axially concentric transition
- Prepared welding ends
- Hydrodynamic optimization
- Test compliance
Technical Notes
- Preferred for vertical lines.
- Prevents air bubble accumulation.
- Fluid velocity changes gradually.
- Pressure drop is minimal.
Related Sectors
Useful Calculation Tools
Detailed Technical Information and Quotation
Contact our expert team for detailed technical documents, application recommendations, and custom size quotations regarding this product type.
Get Technical SupportWhat is a pipe reducer?
A reducer is a butt-weld fitting that joins two pipes of different diameters. There are two types: the concentric reducer (aligned centerlines, symmetric cone) and the eccentric reducer (one flat side, offset centerlines). Dimensions follow ASME B16.9; reducers are produced in carbon, alloy and stainless steel from 1/2" to 48".
Concentric or eccentric?
A concentric reducer keeps the pipe centerline and is standard on vertical runs. The flat side of an eccentric reducer keeps either the bottom (BOP) or top of the pipe level on horizontal runs: at pump suction the flat side goes UP so no air pocket can form; on drained lines and pipe racks the flat side goes DOWN so the pipe bottom stays continuous. The ordering notation is "large end × small end" (e.g. 8"×6"); end-to-end lengths are defined in B16.9. Materials: ASTM A234 WPB (carbon), WP11/WP22 (alloy), A403 (stainless), A420 (low temperature); EN 10253 in Europe. Delivered with 3.1 material certificates.
Frequently Asked Questions
What is the difference between concentric and eccentric reducers?+
A concentric reducer has aligned centerlines (symmetric cone); an eccentric reducer has one flat side and offset centerlines, used to keep the bottom or top of a horizontal line level.
Why use an eccentric reducer at pump suction?+
Installed flat side up, it prevents an air pocket forming at the top of the pipe — air pockets at suction can cause pump cavitation.
How do you order a reducer?+
Specify the "large end × small end" combination (e.g. 8"×6"), type (concentric/eccentric), wall thickness (SCH 40, SCH 80...) and material grade.
Which standards cover reducers?+
Dimensions and tolerances per ASME B16.9 (European equivalent EN 10253); materials per ASTM A234 (carbon/alloy), A403 (stainless) and A420 (low temperature).
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