Sigma 818902579 2 Inch Mnpt Square Head Plug 150 Lb

Product Description

The SIGMA 818902579 is a cored square head plug designed for threaded pipe systems in plumbing, mechanical, and industrial piping applications. With a 2-inch nominal size and male NPT (MNPT) end style, this plug threads directly into female NPT fittings to cap or temporarily close off a pipe run. Constructed from malleable iron with a black oxide finish, it is rated at 150 lb, making it suitable for low-pressure steam, water, oil, and gas service in standard pipe systems. Plumbers and pipefitters install this fitting as part of routine system assembly or pressure-testing procedures.

This square head plug is used in residential and commercial piping systems where a threaded closure is required. The cored design provides a consistent wall thickness throughout the casting. The MNPT thread allows direct engagement with standard female NPT pipe fittings and couplings. It is a common component in mechanical rooms, process piping, and hydronic systems where temporary or permanent pipe capping is needed at 2-inch connection points.

Key Features

• 2-inch nominal MNPT thread for direct engagement with standard female NPT fittings
• 150 lb pressure class rating suitable for water, steam, oil, and gas service
• Malleable iron construction provides strength and resistance to impact and vibration
• Black oxide finish offers corrosion resistance in typical piping environments
• Cored square head design allows positive wrench engagement during installation and removal

Compatibility

Designed as an OEM-style replacement or new-installation fitting compatible with standard 2-inch female NPT threaded pipe connections in 150 lb class piping systems.

Installation Notes

Installation is performed by licensed plumbers or pipefitters using a pipe wrench or socket tool sized to the square head. Shut off and depressurize the piping system completely before installing or removing any threaded fittings. Apply thread sealant tape or pipe dope to the male threads per applicable codes such as the IPC or IFGC before engagement. Do not overtighten, as malleable iron fittings can crack if excessive force is applied.

Technical Specifications

• Nominal Size: 2 inches
• End Style: MNPT (Male National Pipe Thread)
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Black Oxide
• Head Style: Square Head, Cored

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 818902579