B K/mueller Inds 521-365HN Black Reducing Coupling

Product Description

The B K/Mueller Inds 521-365HN is a black reducing coupling designed to connect two pipes of different diameters in threaded piping systems. This fitting reduces from 1.25 inches to 1 inch and features the standard black malleable iron finish common in gas distribution and industrial piping applications. Plumbers and pipefitters use this coupling where a straight-run reduction is needed without introducing a change in direction. Sold in a package of 5 units, it suits contractors who need multiple fittings for larger jobs or service fleets stocking repair inventory.

This reducing coupling is used in residential and light commercial piping systems, particularly in black iron gas line installations and low-pressure steam or air systems. The threaded ends accept standard tapered pipe threads, making it compatible with other black malleable iron fittings and pipe stock. Typical install scenarios include gas branch lines, compressed air distribution, and general industrial fluid conveyance where a reduction in pipe size is required along a straight run.

Key Features

• Reduces from 1.25 inches to 1 inch in a straight-run configuration
• Black finish suitable for gas piping and industrial applications
• Threaded ends for use with standard tapered pipe threads
• Sold in a package of 5 units for multi-fitting jobs
• Compact coupling profile keeps installation footprint minimal

Compatibility

Designed as an OEM-style replacement fitting for threaded black iron piping systems using standard tapered pipe thread connections.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes, including IFGC requirements for gas piping systems. Shut off the gas supply or depressurize the line before disassembling any threaded connections. Apply appropriate thread sealant or PTFE tape rated for the intended service medium before threading the coupling onto pipe. Do not overtighten threaded connections, as this can crack the fitting or distort the threads.