B K/mueller Inds(import) 521-401HN Black Pipe Cap

Product Description

The B K/MUELLER INDS(IMPORT) 521-401HN is a 0.25-inch black iron pipe cap used to close off the open end of a threaded pipe. It threads onto a male NPT fitting to seal the pipe end against flow, pressure, or contamination. This cap is a standard component in gas piping, water distribution, and general plumbing systems. It ships in a pack of 10 units, making it a practical choice for contractors stocking service vehicles or completing multi-point installations. Licensed plumbers and gas fitters install this type of fitting in residential and light commercial applications.

Black iron pipe caps in this size are common in natural gas and propane distribution lines, where they cap unused branch tees, test ports, or future-use connections. They are also used in black steel water and compressed-air piping systems. The 0.25-inch size fits standard quarter-inch NPT threaded pipe ends. The pack quantity of 10 supports multi-cap jobs or ongoing service stock without requiring individual ordering.

Key Features

• 0.25-inch NPT thread size closes off quarter-inch male pipe ends
• Black iron construction suitable for gas, air, and water piping systems
• Pack of 10 units supports stocking and multi-point installations
• Standard threaded end cap design for straightforward hand or wrench installation
• Lightweight at 0.49 pounds per pack of 10

Compatibility

Designed as an OEM-style threaded fitting for use with standard 0.25-inch NPT black iron or steel pipe systems in residential and light commercial plumbing and gas piping applications.

Installation Notes

Installation is performed by a licensed plumber or gas fitter in jurisdictions where pipe work on gas or pressurized systems requires a permit. Shut off gas supply or depressurize the line before threading on the cap. Apply approved pipe thread sealant or PTFE tape to the male threads before installation. Follow applicable codes such as IFGC or IPC for gas and plumbing system work.