Bk 521-401HN Malleable Black Iron Pipe Cap 1/4 in

Product Description

The BK 521-401HN is a 1/4 inch malleable black iron pipe cap designed to terminate open pipe ends in gas, air, and general plumbing systems. Cast from malleable black iron conforming to ANSI/ASTM A-197, this cap meets dimensional standards ANSI/ASME B16.3, B16.14, and B16.39, with threads cut to ANSI B1.20.1. Each fitting is individually flag tagged and 100% inspected and quality tested before shipment. Plumbers, pipefitters, and HVAC technicians use this cap to close off threaded pipe ends during installation, testing, or when capping unused branch connections.

The 521-401HN is suited for residential and light commercial piping systems where a threaded black iron cap is required. Common applications include capping gas supply branch lines, compressed air lines, and other ferrous pipe systems. The fitting weighs 0.067 pounds, making it a standard lightweight cap for 1/4 inch NPT threaded pipe. It is sold individually and is appropriate for new construction, retrofit, and service applications.

Key Features

• Malleable black iron construction per ANSI/ASTM A-197 for durability in ferrous pipe systems
• Threaded to ANSI B1.20.1 NPT standard for reliable sealing on 1/4 inch pipe
• Dimensional compliance with ANSI/ASME B16.3, B16.14, and B16.39
• 100% inspected and quality tested per manufacturer standards
• Individually flag tagged for easy identification and inventory tracking

Compatibility

Designed as an OEM-style replacement and standard-fit cap for 1/4 inch NPT threaded black iron pipe systems in gas, air, and general piping applications.

Installation Notes

Installation is performed by licensed plumbers or pipefitters in accordance with applicable local codes and IFGC or IPC requirements. Shut off and depressurize the supply line before installing or removing any threaded fitting. Apply an appropriate thread sealant or PTFE tape to the male threads before threading on the cap. Do not overtighten; use a pipe wrench and follow standard hand-tight-plus-turns practice to avoid cracking the fitting.

Technical Specifications

• Material: Malleable Black Iron
• Thread Standard: ANSI B1.20.1 NPT
• Pipe Size: 1/4 inch
• Dimensional Standard: ANSI/ASME B16.3, B16.14, B16.39
• Material Standard: ANSI/ASTM A-197
• Weight: 0.067 pounds
• Sold As: Each

Standard Information

• Brand: BK
• Manufacturer Part Number: 521-401HN