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ANSI B16.9 / IS · Concentric & Eccentric
Reducer Fittings
M.S. Concentric & Eccentric Reducer Pipe Fittings – Mumbai, India · Since 1999
ANSI B16.9 / IS CertifiedConcentric & EccentricBW / SW EndsDirect ManufacturerPAN India Supply
M.S. Reducer Pipe Fittings connect two pipes of different nominal bore sizes in a piping system. I.S. Engineering Co. manufactures Concentric Reducers (both pipe centrelines on the same axis) and Eccentric Reducers (one flat side, offset centrelines) from IS:2062 mild steel at our Darukhana, Mumbai factory. Available in all standard NB sizes as per ANSI B16.9 and IS standards with butt weld (BW) or socket weld (SW) ends. Used in oil & gas, water supply, industrial process, HVAC and construction piping wherever a change in pipe bore size is required.
Quick Specifications
StandardANSI B16.9 / IS
TypesConcentric (CON) and Eccentric (ECC)
Size RangeAll Standard NB Sizes Available
End TypesButt Weld (BW) / Socket Weld (SW)
Material GradeIS:2062 Mild Steel (MS)
ApplicationsOil & Gas, Water, Industrial Process
Lead Time3–7 Days
SupplyPAN India | Darukhana, Mumbai
CON & ECCBoth Types
All SizesNB Available
ANSI B16.9Standard
What Are Reducer Fittings?
Reducer Pipe Fittings are used wherever two pipes of different sizes must be joined — for example, connecting a 100mm NB main to a 80mm NB branch, or reducing at the inlet of a pump or control valve. They are available in two types:
- Concentric Reducer (CON): The centrelines of the large and small ends are on the same axis — the reducer is symmetrical top and bottom. Used in vertical piping and horizontal piping where centreline alignment is required.
- Eccentric Reducer (ECC): One face of the reducer is flat (one side straight) — the centrelines of the large and small ends are offset. The flat face can be oriented flat-side-up (BOP — Bottom of Pipe level) or flat-side-down.
Concentric vs Eccentric Reducer — When to Use Which
- Vertical piping: Always use Concentric Reducers — eccentric reducers in vertical runs would create an asymmetric flow condition.
- Horizontal piping — general: Use Concentric Reducers where centreline alignment is required (e.g., equipment connections requiring centreline matching).
- Pump suctions (horizontal): Use Eccentric Reducer flat-side-up (BOP) — keeps the top of pipe level to prevent vapour pockets that cause cavitation at the pump.
- Pump discharges & drain lines: Use Eccentric Reducer flat-side-down (TOP) — keeps bottom of pipe level for drainage.
Why Choose I.S. Engineering Co.?
25+ Years Experience
Manufacturing Reducer Fittings in Mumbai since 1999. Trusted by 500+ clients across India.
Factory-Direct Pricing
No middlemen. Buy direct from the manufacturer at the most competitive prices in Mumbai.
100% Quality Inspected
Every Reducer Fittings undergoes dimensional and material inspection before dispatch from our Mumbai factory.
PAN India Delivery
Supplying to Mumbai, Pune, Delhi, Bangalore, Chennai, Hyderabad, Ahmedabad and all major cities across India.
Reducer Fittings – Dimensional Specifications
| Large End NB | Small End NB | Concentric Length (mm) | Eccentric Length (mm) | Available Types |
|---|---|---|---|---|
| 25mm (1") | 15mm (½") | 38 | 38 | CON / ECC |
| 50mm (2") | 25mm (1") | 51 | 51 | CON / ECC |
| 50mm (2") | 40mm (1½") | 51 | 51 | CON / ECC |
| 80mm (3") | 50mm (2") | 64 | 64 | CON / ECC |
| 100mm (4") | 80mm (3") | 76 | 76 | CON / ECC |
| 100mm (4") | 50mm (2") | 76 | 76 | CON / ECC |
| 150mm (6") | 100mm (4") | 89 | 89 | CON / ECC |
| 200mm (8") | 150mm (6") | 102 | 102 | CON / ECC |
| 250mm (10") | 200mm (8") | 127 | 127 | CON / ECC |
| 300mm (12") | 250mm (10") | 152 | 152 | CON / ECC |
* Dimensions are indicative. Custom sizes available on request. Contact I.S. Engineering Co. at +91 83558 15350 for specific sizes, tolerances and full specification sheets.
Reducer Fittings – Industries & Applications
Pump Connections
Most critical reducer application. Eccentric Reducer flat-side-up at pump suctions prevents air/vapour pockets that cause cavitation. Eccentric Reducer flat-side-down at pump discharges for drainage. Critical for centrifugal pump protection.
Pipeline Diameter Changes
Used wherever a transmission main or distribution pipe changes diameter — for example at zone boundaries, at offtakes or where pipe size is reduced to match flow requirements further down the line.
Equipment Connections
Connecting pipes to equipment nozzles of different NB sizes — vessels, heat exchangers, control valves, flow meters and other process equipment with smaller or larger nozzle sizes than the connecting pipe.
Oil & Gas Pipelines
Used in pipeline tee connections where a larger transmission main connects to a smaller distribution branch, and at scraper trap connections, pig launchers and pressure let-down stations.
HVAC & Water Systems
Used in HVAC chilled water and heating systems at air handling units, fan coil connections and where header pipes branch into smaller distribution pipes serving multiple zones.
Reducer Fittings – Frequently Asked Questions
What are Reducer Pipe Fittings?
+Reducer Pipe Fittings connect two pipes of different nominal bore (NB) sizes. Available in Concentric (CON) — both centrelines on same axis — and Eccentric (ECC) — one flat side, offset centrelines — types. Manufactured from IS:2062 mild steel to ANSI B16.9 with butt weld or socket weld ends.
What is the difference between Concentric and Eccentric Reducers?
+Concentric Reducers: Symmetrical — large and small end centrelines are on the same axis. Used in vertical piping and horizontal piping where centreline alignment is required. Eccentric Reducers: One side is flat (straight) — large and small end centrelines are offset. Installed flat-side-up at pump suctions (to prevent air pockets / cavitation) and flat-side-down at pump discharges (for drainage). Never use Concentric Reducers at horizontal pump suctions — always specify Eccentric.
How do I specify a Reducer Fitting when ordering?
+Specify: (1) Type — Concentric (CON) or Eccentric (ECC); (2) Large end NB — e.g., 100mm NB; (3) Small end NB — e.g., 80mm NB; (4) End type — Butt Weld (BW) or Socket Weld (SW); (5) Quantity in numbers (nos.). Example order: '100×80mm NB Eccentric Reducer BW ANSI B16.9, 10 nos.' Contact I.S. Engineering Co. at +91 83558 15350 for pricing.
Why use an Eccentric Reducer flat-side-up at pump suctions?
+At horizontal centrifugal pump suctions, using an Eccentric Reducer with flat-side-up (BOP — Bottom Of Pipe level) keeps the bottom of the pipe level — preventing any high point in the suction line where vapour or air can accumulate. If a Concentric Reducer or wrong-orientation Eccentric is used at pump suctions, air/vapour pockets form at the high point and are drawn into the pump, causing cavitation — damaging the pump impeller and reducing efficiency.
What end types are available for Reducer Fittings?
+I.S. Engineering Co. supplies M.S. Reducer Fittings in: Butt Weld (BW) ends — the pipe end is bevelled and butt-welded to the pipe, suitable for all pipe schedules and pressure classes; Socket Weld (SW) ends — the pipe inserts into a socket, externally fillet-welded, for small bore high-pressure applications. Butt weld reducers are the standard specification for most industrial process and water piping.
Are Tee Fittings also available from I.S. Engineering Co.?
+Yes. I.S. Engineering Co. also supplies M.S. Tee Pipe Fittings — both Equal Tees (all three outlets same NB) and Reducing Tees (smaller branch NB) — in butt weld ends to ANSI B16.9. Sizes 15mm NB to 300mm NB. Also available: M.S. Pipe End Caps (butt weld, ANSI B16.9, all sizes). Contact us at +91 83558 15350 for pricing and availability.
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