Indus Industrial Group supplies heavy-duty Stepped Universal Transition Couplings engineered in nominal diameter combinations from DN50 (2") to DN1000 (40") in working pressure class PN16. Conforming to EN 14525 and EN 545 specifications, these stepped mechanical couplings feature an asymmetrical ductile iron center sleeve and independently sized end compression rings designed specifically to join two pipes of the same nominal bore but drastically different outside diameters—such as connecting thick-walled legacy Asbestos Cement (AC) or Cast Iron to modern thin-walled Steel or Ductile Iron pipes across Iraq.
| Pricing Verification | Commercial Quote on Demand (RFQ) |
| Nominal Bore Sizes | DN50 to DN1000 (2" to 40") Standard Stepped Combinations |
| Working Pressure Rating | PN16 (16 Bar continuous) / Shell Test 24 Bar |
| Stepped Diameter Difference | Accommodates up to 30mm to 65mm step difference between pipe ODs |
| Body Sleeve Material | Ductile Iron EN-GJS-450-10 (high tensile impact strength) |
| Gasket Elastomer | EPDM (Potable Water WRAS approved) / NBR (Sewage & Hydrocarbons) |
| Protective Coating | Thermal Fusion-Bonded Epoxy (FBE) min 250 μm (DIN 30677-2) |
| Tie Rod Fasteners | High-Tensile Grade 8.8 Dacromet Coated Steel / Stainless Steel AISI 316 |
| Angular Deflection | Up to 3.0° to 4.0° per pipe end |
| Governing Standards | EN 14525 / EN 545 / ISO 2531 / WRAS Approved |
| Sector & Division | Water & Wastewater (Div 01) |
| Parent Category | Wide-Tolerance Couplings & Restraint Adapters |
Connecting legacy asbestos cement water mains to modern ductile iron pipes, network renewal in old city centers, and emergency repair of non-standard diameter pipelines in Baghdad, Mosul, Basra, Kirkuk, and Najaf.
Urban pipeline rehabilitation projects in historical Iraqi cities like Baghdad, Mosul, Kirkuk, and Basra frequently encounter legacy pipelines where the outside diameter difference between the existing buried pipe and modern replacement pipe exceeds the tolerance range of a standard straight coupling. Stepped Universal Transition Couplings provide an engineered solution by stepping the center sleeve casting and utilizing different gasket diameters on either end.
Manufactured from high-tensile spheroidal graphite ductile iron (EN-GJS-450-10) coated with minimum 250 microns of WRAS-approved fusion-bonded epoxy, each end of the stepped coupling operates independently. The large-diameter end accommodates heavy Class 20 or Class 25 Asbestos Cement pipes (which have exceptionally thick walls), while the small-diameter end seals tightly around modern ISO 2531 ductile iron or steel pipe.
The dual EPDM rubber sealing rings are molded with deep multi-stage sealing ribs that seal drop-tight even on pitted, grooved, or out-of-round pipe surfaces common in legacy networks. Long stainless steel or galvanized tie bolts span across the center sleeve, allowing field crews to tighten the fitting uniformly in cramped trenches. Staged in popular transition sizing combinations at Indus Erbil and Baghdad central depots.
A stepped coupling is required when the difference between the two pipe outside diameters exceeds 40mm (such as connecting a Class 25 Asbestos Cement pipe to a modern thin-walled steel pipe), where a straight coupling cannot clamp both sides evenly.
Yes. Our EPDM gaskets feature thick, multi-ribbed sealing geometry that deforms deeply into surface irregularities, scratches, and minor pitting on old cast iron and concrete surfaces to guarantee watertightness.
Yes. We supply high-tensile steel bolts treated with anti-corrosion Dacromet coating plus zinc plating, or optional marine-grade AISI 316 stainless steel bolts for extreme soil environments.
