B K/mueller Inds(import) 521-228HC Black Merchant Coupling

Product Description

The B K/MUELLER INDS(IMPORT) 521-228HC is a 2-inch black merchant coupling designed for joining threaded black iron pipe sections in gas, air, and general-purpose piping systems. This fitting is a standard malleable or cast iron merchant-pattern coupling, recognizable by its longer thread engagement compared to a standard coupling. Plumbers, pipefitters, and gas service technicians install this fitting in both residential and light commercial applications. The black finish indicates an uncoated iron fitting suitable for gas distribution and similar non-potable service lines.

This coupling is used in black iron pipe assemblies where a full-length threaded connection is required. Typical applications include natural gas supply lines, propane distribution, compressed air piping, and industrial fluid conveyance. The merchant-pattern design provides additional thread engagement for joints that require added mechanical strength. It is commonly found in basement and utility room gas rough-in work, rooftop mechanical connections, and equipment branch feeds.

Key Features

• 2-inch nominal pipe size fits standard 2-inch NPT threaded black iron pipe
• Merchant coupling pattern provides longer thread engagement than a standard coupling
• Black iron construction suited for gas, air, and general industrial piping service
• Sold in a package quantity of 9 units per pack

Compatibility

Designed as an OEM-style replacement and standard-stock fitting for 2-inch NPT black iron pipe systems in residential and commercial gas and air piping applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes, IFGC requirements for gas service, and ASME B16.3 standards for malleable iron fittings. Shut off all gas or air supply and verify the line is fully depressurized before removing or installing any threaded fitting. Apply an approved pipe thread sealant or PTFE tape rated for the intended service medium to all male threads before assembly. Do not over-tighten threaded fittings; use a pipe wrench and backup wrench to avoid stressing adjacent joints.