Pipe Reducers
NUMET ALLOYS precision-engineers industrial pipe reducers designed for seamless transitions between varying pipeline diameters. Available in both Concentric and Eccentric configurations, our reducers are forged to mitigate pressure drops, eliminate flow turbulence, and provide critical structural integrity during heavy-duty fluid transportation.
Detailed Technical Specifications
Eccentric (ER): Flat on one side, offset centerline (Horizontal/Pump suction lines).
Stainless Steel: ASTM A403 WP304/304L, WP316/316L, WP321, WP347
Alloy Steel: ASTM A234 WP1, WP5, WP9, WP11, WP22, WP91
Welded (ERW/SAW): 24" NB to 48" NB (100% Radiography Tested)
Note: Thickness can be matched to either the large or small bore end.
Dimensions (ASME B16.9)
Reducer length is governed by the larger end only — every reduction from a given size shares the same end-to-end length, and concentric and eccentric reducers of the same pairing are identical in length. A 6" × 4", 6" × 3" and 6" × 2-1/2" reducer are therefore all 140 mm long.
Concentric & Eccentric Reducers — End-to-End Length (H)
ASME B16.9| Larger EndNPS | Outside Dia.mm | Length Hmm | Length Hinch |
|---|---|---|---|
| 3/4 | 26.7 | 38 | 1.50 |
| 1 | 33.4 | 51 | 2.00 |
| 1-1/4 | 42.2 | 51 | 2.00 |
| 1-1/2 | 48.3 | 64 | 2.50 |
| 2 | 60.3 | 76 | 3.00 |
| 2-1/2 | 73.0 | 89 | 3.50 |
| 3 | 88.9 | 89 | 3.50 |
| 3-1/2 | 101.6 | 102 | 4.00 |
| 4 | 114.3 | 102 | 4.00 |
| 5 | 141.3 | 127 | 5.00 |
| 6 | 168.3 | 140 | 5.50 |
| 8 | 219.1 | 152 | 6.00 |
| 10 | 273.1 | 178 | 7.00 |
| 12 | 323.9 | 203 | 8.00 |
| 14 | 355.6 | 330 | 13.00 |
| 16 | 406.4 | 356 | 14.00 |
| 18 | 457.2 | 381 | 15.00 |
| 20 | 508.0 | 508 | 20.00 |
| 24 | 609.6 | 508 | 20.00 |
Note the step at NPS 14: length jumps from 203 mm to 330 mm, so lengths cannot be interpolated between sizes. ASME B16.9 tabulates specific reductions only — the small end cannot be arbitrarily small (for example, 6" × 2-1/2" is the smallest standard 6" reduction). NPS 22 reducers are supplied to the same 508 mm length as NPS 20 and 24; confirm at the time of enquiry.
Dimensions are nominal values from the referenced standard and are shown for reference only; tolerances apply as specified in the standard. Sizes above 24" NB and non-standard combinations are manufactured to order. For certified drawings against your line list, contact our technical team.
Core Advantages
Smooth Flow Transition
The precisely calculated taper angle gradually reduces fluid velocity and pipeline space, effectively mitigating sudden pressure spikes and water hammer effects.
Cavitation Prevention
Eccentric reducers feature a flat-side profile (Top-Flat or Bottom-Flat) specifically designed to eliminate air/vapor pockets at pump suction intakes, preventing severe mechanical damage.
Optimal Stress Distribution
Forged without sharp corners or abrasive internal steps, ensuring that thermal and mechanical stress is evenly distributed across the varying pipe diameters.