Bk Mueller 591-050BC Black Steel Pipe Nipple 4x5 Sch 40

Product Description

The BK MUELLER 591-050BC is a Schedule 40 black steel pipe nipple used to create threaded connections in gas, air, and general-purpose piping systems. Measuring 4 inches in diameter and 5 inches in length, it fits standard NPT fittings and is well suited for connecting pipes, valves, and fittings in both residential and commercial installations. The black finish is applied after threading and is standard for gas-line applications. Plumbers, pipefitters, and HVAC technicians install this type of nipple where a short, rigid threaded extension is needed between components.

This nipple is used in a wide range of piping applications including natural gas distribution, compressed air lines, steam systems, and general water or fluid transfer where Schedule 40 wall thickness meets the pressure requirements of the installation. It is commonly found in mechanical rooms, utility connections, and industrial piping runs. Its 4-inch nominal pipe size makes it appropriate for main distribution lines and large-diameter branch connections in commercial and light industrial settings.

Key Features

• Schedule 40 wall thickness suitable for standard-pressure piping applications
• 4-inch nominal pipe size with 4-inch NPT thread on both ends
• 5-inch overall length for short extension connections
• Black finish standard for gas-line and general mechanical piping use
• Steel construction for durability in high-demand piping systems

Compatibility

Designed as a standard NPT-threaded Schedule 40 black steel pipe nipple compatible with 4-inch NPT fittings, valves, and couplings used in gas, air, steam, and general-purpose piping systems.

Installation Notes

This nipple is typically installed by licensed plumbers or pipefitters working under applicable mechanical or gas codes such as the IFGC or IPC. Shut off and depressurize the line before installation and verify thread engagement with a calibrated thread gauge before applying sealant or tape. Use a proper pipe wrench or strap wrench sized for 4-inch pipe to avoid thread damage. For gas service, use only approved thread sealant compounds rated for gas and verify the completed assembly for leaks before returning the system to service.