6 inch x 4 inch PVC DWV Reducing Coupling Plastic x Plastic

6" x 4" PVC DWV Reducing Coupling – Socket x Socket Transition for Gravity Drainage Systems

The 6" x 4" PVC DWV Reducing Coupling is designed to join Schedule 40 DWV piping systems of dissimilar diameters. It features solvent-weld socket ends to provide a secure, leak-resistant bond between 6-inch and 4-inch nominal pipes. Commonly used in drainage, waste, and vent (DWV) configurations, this fitting is intended for non-pressurized, gravity-flow systems.

Manufactured from Type I Grade I polyvinyl chloride (PVC) conforming to ASTM D2665, this coupling provides chemical resistance, dimensional stability, and long-term performance in residential and commercial DWV systems. Its reducing profile is specifically engineered to maintain flow characteristics while transitioning between pipe sizes.

Technical Specifications

• Nominal Sizes: 6 inch x 4 inch
• Connection Type: Socket x Socket (solvent weld)
• Material: PVC (Cell Class 12454 per ASTM D1784)
• Standards: ASTM D2665, NSF 14 certified, CSA B181.2 compliant
• Temperature Rating: Up to 140°F (60°C) for drainage applications

Installation Guidelines

Join using a two-step solvent cement and primer process in accordance with ASTM D2855. Pipe ends must be square-cut, deburred, and dry-fitted before assembly. Ensure proper alignment and insertion depth to maintain slope and system integrity. Not suitable for pressure applications or use with threaded components.

Common Applications

This reducing coupling is used in sanitary drainage configurations where a change in pipe diameter is required—typically in vertical stacks, horizontal mainlines, and branch drains. Suitable for underground and above-ground installations per local code.

Design Insight

PVC DWV fittings are engineered with smooth interior surfaces to minimize friction loss and promote laminar flow. The reducing coupling helps avoid flow turbulence by providing a concentric transition between pipe sizes, improving long-term system performance.

Code-Grade Reducing Fitting for DWV Systems

The 6" x 4" PVC DWV Coupling offers a reliable, solvent-welded transition point in gravity-based waste and vent systems. Built to meet industry specifications for sanitary drainage, this fitting ensures dimensional accuracy and durability in new construction and retrofit projects alike.