B K Mueller 521-004HC 3/4 Inch Black Cross Fitting

Product Description

The B K Mueller Industries 521-004HC is a 3/4-inch black cross pipe fitting used to create four-way junctions in threaded pipe systems. This malleable iron fitting connects four sections of pipe at right angles and is suited for low-pressure gas distribution, compressed air lines, and general industrial piping. Licensed plumbers and pipefitters install this type of fitting in both residential and light commercial applications. The black finish indicates an uncoated malleable iron construction, which distinguishes it from galvanized fittings and makes it a standard choice for gas service lines.

This cross fitting is used where a single run of pipe must branch in two directions simultaneously. It is common in black iron gas piping systems for natural gas and propane, as well as in compressed air distribution and fire suppression rough-in work. The four-way configuration allows a main line to feed two lateral branches from a single connection point, reducing the number of fittings and potential leak points in complex piping layouts.

Key Features

• Four-way cross configuration for branching threaded pipe runs
• 3/4-inch nominal pipe size on all four ports
• Black malleable iron construction for gas and industrial service
• Threaded connections compatible with standard NPT pipe threads
• Sold in a package quantity of 30 units per case

Compatibility

Designed as an OEM-style replacement and standard cross fitting for 3/4-inch NPT threaded black iron pipe systems used in residential and commercial gas distribution and industrial piping applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes and IFGC requirements for gas piping systems. Shut off gas supply or depressurize the line completely before making or breaking any threaded connections. Apply an appropriate thread sealant or PTFE tape rated for gas service to all male threads before assembly. Do not over-tighten threaded connections, as this can crack the fitting body.