Bk Mueller 511-805HP Malleable Iron Square Plug 1 Inch

Product Description

The BK MUELLER 511-805HP is a malleable iron square plug fitting designed to close off threaded pipe ends in piping systems carrying liquid, gas, or steam. Rated at 300 psi for liquid and gas service and 150 psi for steam, this Class 150 fitting delivers reliable sealing performance across a wide range of pressures. The galvanized finish provides corrosion resistance for longevity in demanding environments. At 1 inch in size with a threaded end connection, it installs quickly into standard female pipe threads. Plumbers, pipefitters, and mechanical contractors commonly use square plugs like this to cap unused branch outlets, test ports, or service ports during installation and maintenance work.

This fitting is suited for residential and light commercial piping systems where liquid, gas, or low-pressure steam lines require a secure threaded closure. It is a practical choice for capping iron pipe runs during pressure testing, isolating unused tee branches, or permanently closing off ports after system modifications. The malleable iron construction handles the mechanical stress of wrench-tightened connections without cracking, making it appropriate for in-wall, below-slab, or mechanical-room installations where vibration or thermal cycling may be present.

Key Features

• Malleable iron construction resists cracking under wrench torque and thermal cycling
• Galvanized finish provides corrosion resistance for extended service life
• Rated 300 psi for liquid and gas service
• Rated 150 psi for steam service
• Threaded end connection for straightforward installation into female pipe threads
• Class 150 fitting meeting standard pipe fitting classifications

Compatibility

Designed as an OEM-style replacement or new-installation fitting compatible with standard 1 inch female threaded malleable iron or steel pipe fittings in Class 150 piping systems.

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 piping system completely before removing or installing any fitting. Apply thread sealant or PTFE tape to the male threads before tightening to achieve a leak-free seal. Tighten using a pipe wrench on the square drive head; do not over-tighten, as this can damage threads or the fitting body.