Bk Mueller 521-373HC Reducing Coupling 1-1/2 X 1/2 in

Product Description

The BK MUELLER 521-373HC is a black malleable iron reducing coupling designed for threaded pipe connections in gas and liquid distribution systems. It transitions from a 1-1/2 inch female iron pipe (FIP) thread to a 1/2 inch FIP thread, allowing diameter reduction within a single fitting. The Class 150 rating and 300 psi pressure rating make it suitable for both residential and light commercial piping applications. Licensed plumbers and pipefitters install this fitting as part of natural gas, propane, or water distribution runs where a step-down in pipe size is required at a branch or terminal connection.

This reducing coupling is used in residential and commercial gas piping systems, potable water supply lines, and industrial fluid distribution where malleable iron fittings are specified. The black finish is standard for gas service applications and distinguishes it from galvanized fittings used in water service. It is well-suited for exposed or in-wall piping runs where a durable, pressure-rated threaded connection is needed between two different pipe diameters.

Key Features

• Malleable iron construction rated to 300 psi for gas and liquid service
• FIP x FIP threaded connection on both ends - no special tools required for assembly
• Reduces from 1-1/2 inches to 1/2 inch in a single fitting
• Black finish meets standard requirements for gas distribution piping identification
• Class 150 classification suitable for residential and light commercial systems

Compatibility

Designed as an OEM-style replacement or new-installation fitting for threaded malleable iron pipe systems using 1-1/2 inch and 1/2 inch FIP connections.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with IFGC or IPC requirements as applicable to the service type. Shut off all gas or water supply and verify zero pressure in the line before threading or unthreading any fitting. Apply appropriate pipe thread sealant rated for the intended service - use a gas-rated compound or tape for gas lines. Do not overtighten threaded connections; hand-tighten and finish with a pipe wrench, checking all joints for leaks before returning the system to service.