Bk 521-206BG Malleable Black Iron Coupling 1-1/4 in

Product Description

The BK 521-206BG is a 1-1/4-inch malleable black iron coupling designed for joining threaded pipe sections in gas, water, and general piping systems. Manufactured from malleable iron conforming to ANSI/ASTM A-197, the fitting meets dimensional standards ANSI/ASME B16.3, B16.14, and B16.39, with threads cut to ANSI B1.20.1 NPT specification. Each fitting is individually flag tagged and 100% inspected at the factory. The Mueller logo is cast directly into the body. Plumbers, pipefitters, and HVAC technicians use this coupling in both residential and light commercial installations where a straight, same-size pipe connection is required.

The 521-206BG is suited for use in threaded black iron piping systems, including natural gas distribution, compressed air lines, and steam or water piping where black iron fittings are specified. The 1-1/4-inch size is common in branch and main-line runs in residential and small commercial mechanical rooms. Sold individually, making it practical for service calls and small repair jobs without requiring a bulk purchase.

Key Features

• Malleable iron construction per ANSI/ASTM A-197 for strength and machinability
• Dimensions conform to ANSI/ASME B16.3, B16.14, and B16.39
• NPT threads per ANSI B1.20.1 for reliable sealed connections
• 100% factory inspected and quality tested
• Individually flag tagged for easy identification and inventory management
• Mueller logo cast into body for quick brand verification on the job

Compatibility

Designed as an OEM-style replacement or new-installation fitting for 1-1/4-inch NPT threaded black iron piping systems in gas, steam, air, and water applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes, the International Fuel Gas Code (IFGC), or the International Plumbing Code (IPC) as required by the system type. Shut off and depressurize the line before disassembling any existing fittings. Apply an approved pipe thread sealant or PTFE tape rated for the intended service medium before making up the joint. Do not over-tighten; use a pipe wrench with a backup wrench on the mating component to avoid stressing adjacent fittings.

Technical Specifications

• Material: Malleable Black Iron, ANSI/ASTM A-197
• Size: 1-1/4 inches
• Thread Standard: ANSI B1.20.1 NPT
• Dimensional Standards: ANSI/ASME B16.3, B16.14, B16.39
• Weight: 0.682 pounds
• Sold As: Each

Standard Information

• Brand: BK
• Manufacturer Part Number: 521-206BG