Bk Mueller 521-330HC Black Reducing Coupling 1/2x1/8

Product Description

The BK MUELLER 521-330HC is a black malleable iron reducing coupling designed to connect two threaded pipe sections of different sizes in a single inline fitting. It transitions from a 1/2-inch female iron pipe (FIP) thread to a 1/8-inch FIP thread, making it a standard component in low-pressure gas, air, and fluid distribution systems. Rated at 300 psi and classified as Class 150, this coupling handles typical residential and light commercial service pressures without issue. The black finish is standard for gas piping applications. Installation requires no special tooling beyond pipe wrenches and thread sealant appropriate for the service medium.

This reducing coupling fits into threaded malleable iron piping systems used in residential and commercial gas distribution, compressed air lines, and general plumbing applications. It is commonly installed at branch takeoffs, meter sets, appliance connections, and any point where a larger pipe run feeds into a smaller downstream line. The FIP-to-FIP threaded connection on both ends allows it to mate directly with male-threaded nipples, valves, and other fittings without adapters.

Key Features

• Reduces from 1/2-inch to 1/8-inch FIP threaded connection in a single fitting
• Malleable iron construction rated for 300 psi liquid and gas service
• Class 150 classification for standard low-pressure piping systems
• Black finish suitable for natural gas and propane piping installations
• Female iron pipe (FIP) threads on both ends for direct inline installation
• Sold individually with no minimum order requirement beyond single-unit quantities

Compatibility

Designed as an OEM-style replacement or new-installation fitting for Class 150 threaded malleable iron piping systems using 1/2-inch and 1/8-inch FIP connections.

Installation Notes

Installation is performed by licensed plumbers or qualified gas fitters, depending on the service medium and local jurisdiction requirements. Shut off and depressurize the line before disassembling any existing fittings. Apply an approved thread sealant or PTFE tape rated for the intended service - gas, air, or liquid - before making up the joint. Verify all threaded connections for leaks after restoring pressure, in accordance with IFGC or IPC requirements as applicable.