Bk 521-200HC Malleable Black Iron Coupling 1/8 Inch

Product Description

The BK 521-200HC is a 1/8 inch malleable black iron pipe coupling designed for threaded pipe assemblies in plumbing, gas distribution, and mechanical piping systems. Malleable iron construction meets ANSI/ASTM A-197 material standards, while threads conform to ANSI B1.20.1 for reliable, leak-resistant connections. Dimensions comply with ANSI/ASME B16.15, B16.14, and B16.39. Each fitting is individually flag tagged for traceability and is 100 percent inspected and quality tested before leaving the facility. Licensed plumbers and pipefitters typically install this fitting in low-pressure gas and water piping systems where a straight, threaded union between two pipe ends is required.

This coupling is suited for residential and light commercial piping applications including natural gas, propane, steam, and water service lines. The 1/8 inch thread size targets small-diameter branch lines and instrument connections commonly found in HVAC gas trains, boiler trim, and utility piping. Its compact size and standard thread pattern make it a straightforward drop-in component during new construction or repair work.

Key Features

• Malleable black iron construction meets ANSI/ASTM A-197 material specification
• Threads cut to ANSI B1.20.1 for standard NPT compatibility
• Dimensions conform to ANSI/ASME B16.15, B16.14, and B16.39
• 100 percent inspected and quality tested at the factory
• Individually flag tagged for easy identification and traceability
• 1/8 inch size suits small-diameter branch and instrument piping

Compatibility

Designed as an OEM-style replacement or new-installation fitting for standard 1/8 inch NPT threaded pipe systems in plumbing, gas, and mechanical piping applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable codes such as the IPC or IFGC. Shut off and depressurize the supply line completely before removing or installing any threaded fitting. Apply an approved thread sealant or PTFE tape to male threads before assembly, and tighten to hand-tight plus the appropriate number of turns for the fitting size per trade practice. Do not over-tighten malleable iron fittings, as this can crack the casting.

Technical Specifications

• Material: Malleable Black Iron, ANSI/ASTM A-197
• Thread Standard: ANSI B1.20.1 (NPT)
• Dimensional Standard: ANSI/ASME B16.15, B16.14, B16.39
• Pipe Size: 1/8 inch
• Weight: 0.063 pounds
• Sold As: Each

Standard Information

• Brand: BK
• Manufacturer Part Number: 521-200HC