1-1/4 inch Copper DWV Reducing Trap Adapter Copper x Slip Joint

1-1/4” Copper Trap Adapter – Copper x Slip Joint Transition for DWV Applications

The 1-1/4” copper trap adapter is designed for use in drainage, waste, and vent (DWV) systems requiring a secure transition between rigid copper tubing and slip joint tailpieces. This fitting provides a mechanically reliable and code-compliant method for connecting lavatory or sink drains to the system's copper branch lines.

Constructed from wrought copper, this adapter includes a solder cup on one end and a machined slip joint outlet on the other, allowing for easy disassembly and maintenance access at the fixture. It is intended for use in non-pressurized DWV systems and is compliant with lead-free material standards.

Specifications

• ✅ Nominal Size: 1-1/4 inch
• ✅ End Connections: Copper solder cup x slip joint
• ✅ Material: Wrought copper (typically Alloy C12200)
• ✅ Application Rating: Gravity drainage, non-pressurized DWV systems
• ✅ Compliance: Lead-free per NSF/ANSI 61 and 372

Functional Characteristics

• ✅ Secure Fixture Transition – Joins copper drain lines to slip joint tailpieces at sinks or lavatories
• ✅ Removable Connection Point – Allows for trap servicing or replacement without cutting into the hard pipe
• ✅ DWV-Specific Geometry – Designed with sufficient wall thickness for waste system applications, not suitable for pressure systems
• ✅ Thermally Stable – Suitable for use with soldered joints in residential and commercial construction
• ✅ Compatible with Standard Slip Nuts – Accepts conventional 1-1/4” plastic or brass slip nuts and washers

Installation Guidelines

Installation involves standard copper soldering practices on the inlet side and compression or slip nut assembly on the outlet side. Ensure pipe ends are cleaned and properly fluxed before soldering. Tighten slip nuts to manufacturer torque specifications to avoid deformation or leakage at the seal.

Typical Applications

This fitting is commonly installed in bathroom or kitchen sink drains, where the fixture's trap arm requires connection to a horizontal or vertical copper DWV branch. It is frequently used behind walls, within cabinetry, or at the stub-out termination of waste lines.

Material Note

Wrought copper used in DWV systems provides resistance to corrosion and scaling in waste environments. While not designed for pressure-rated service, its dimensional stability and long service life make it a standard material in residential and light commercial drainage systems.

The 1-1/4” copper trap adapter supports system integrity and service access in building drainage applications, aligning with IPC/UPC code standards for DWV construction.