B K/mueller Inds(import) 521-706HN Black Union 1-1/4 in

Product Description

The B K/MUELLER INDS(IMPORT) 521-706HN is a 1-1/4 inch black union constructed from brass and iron. Unions are three-piece fittings used to join two sections of pipe in a way that allows for future disconnection without cutting. This fitting is designed for gas or liquid piping systems where serviceability matters — the union joint lets a technician break the line cleanly for component removal or system repair. Licensed plumbers and gas fitters install this type of fitting as part of standard black iron piping assemblies in residential and light commercial applications. Each package contains 5 units, and total package weight is 5.72 pounds.

Black iron unions like the 521-706HN are common in natural gas and propane supply lines, as well as in some steam and water piping systems. The 1-1/4 inch size is frequently used in main gas supply runs and branch lines serving high-demand appliances such as boilers, furnaces, commercial ranges, and unit heaters. The brass seat in the union end provides a reliable metal-to-metal seal at the joint face, reducing the likelihood of leak points over repeated make-and-break cycles.

Key Features

• 1-1/4 inch nominal pipe size fits standard black iron pipe threads
• Brass and iron construction provides corrosion resistance at the sealing surface
• Three-piece union design allows pipe disconnection without cutting or unthreading long pipe runs
• Sold in a package of 5 units for multi-joint jobs or stocking purposes
• Black finish is standard for gas piping applications per common trade practice

Compatibility

Designed as an OEM-style replacement or new-installation fitting for 1-1/4 inch black iron pipe systems in residential and commercial plumbing and gas piping applications.

Installation Notes

Black iron unions are installed by licensed plumbers or gas fitters in accordance with the International Fuel Gas Code (IFGC) or International Plumbing Code (IPC) as applicable. Shut off the gas supply or isolate the piping section and relieve system pressure before beginning work. Apply an approved pipe thread sealant or thread tape rated for the service type to all male threads before assembly. Do not over-tighten the union nut — hand-tight plus a measured turn with a pipe wrench is standard; refer to local code and the sealant manufacturer for joint finishing requirements.