5 inch x 4 inch Cast Iron Soil Service Weight Reducing Coupling

5 inch x 4 inch Cast Iron Service Weight Reducing Coupling – Built for System Integrity and Flow Efficiency

The 5 inch x 4 inch Service Weight Reducing Coupling by Charlotte Pipe is engineered for transitioning between different cast iron pipe sizes in soil and waste systems. Manufactured to ASTM A74 specifications, this hub-style fitting supports vertical and horizontal installations requiring consistent structural strength and reliable sealing under gravity-flow conditions.

This coupling is ideal for adapting 5-inch to 4-inch service weight cast iron pipe, facilitating uniform flow transitions while maintaining code compliance. The robust design ensures long-term performance in demanding residential and commercial drainage applications.

Product Benefits for Code-Compliant Systems

• ✅ High-Strength Cast Iron – Manufactured from gray cast iron conforming to ASTM A74, designed for use in DWV (drain, waste, and vent) systems.
• ✅ Precision Hub Fit – Engineered to accommodate pipe ends within hub fittings for rigid, watertight assembly with lead and oakum or mechanical compression gaskets.
• ✅ Durable Wall Thickness – Service weight design supports underground and above-ground installations with excellent load-bearing capacity.
• ✅ Reliable Flow Transition – Provides an accurate reduction in diameter while maintaining consistent hydraulic performance in waste systems.
• ✅ Interchangeable Compatibility – Designed for standard hub-and-spigot cast iron systems without requiring special adapters.

Specifications

• Material: Cast Iron (ASTM A74 Service Weight)
• Size: 5 inch x 4 inch
• Connection: Hub x Hub
• Application: Drain, Waste, and Vent (DWV)
• Certification: Complies with ASTM A74 and CISPI 301 standards

Common Installations

Used in gravity-fed sanitary systems for multi-story residential, commercial, and institutional buildings, this reducing coupling enables transitions where pipe downsizing is needed without compromising structural or hydraulic performance. Common in vertical stacks, horizontal branch lines, and retrofit projects requiring dimensional adjustments.

Note for Installation Professionals

Install with proper hub sealing methods according to code—either lead and oakum or approved neoprene gaskets. Use of mechanical joint couplings for joining bell-and-spigot components is acceptable where permitted. Always refer to local plumbing codes and specifications for compliant practices.

Performance Tip

Cast iron DWV systems are valued for their acoustic dampening, noncombustibility, and longevity. Properly installed reducing couplings help maintain system integrity across varied pipe diameters while preserving code compliance and performance continuity.

The 5 inch x 4 inch Service Weight Reducing Coupling provides professional-grade reliability for cast iron DWV transitions. Designed for longevity and engineered for fit, it supports quality installations that meet structural and hydraulic demands in real-world plumbing environments.