The B&K 1-1/2-in MIP Black Iron Plug (Model 521-807HN) is a square head plug designed to seal off female threaded fittings or pipes in non-potable plumbing and industrial systems. Constructed from black malleable iron, this plug is part of the 150-lb class fittings and is engineered for high-pressure applications. It is ideal for transporting lubricants, oils, greases, liquefied petroleum gases, natural gases, steam, and diesel.

This plug is not intended for potable water systems but excels in industrial environments where durability and sealing performance are critical. The threaded ends conform to ANSI/ASME B1.20.1 standards, and the relative softness of the metal helps ensure a secure seal under pressure.

Key Features

• Material: Black malleable iron
• Connection Type: MIP (Male Iron Pipe)
• Head Type: Square head
• Fitting Class: 150-lb malleable fittings
• Pressure Rating: Up to 500 PSI at 150°F
• Thread Standard: ANSI/ASME B1.20.1
• Seal Quality: Enhanced by the relative softness of the metal
• Compliance: Meets ASTM and ASME standards

Applications

• Lubricant transport systems
• Oil and grease lines
• Liquefied petroleum (LP) gas systems
• Natural gas systems (e.g., nitrogen, oxygen)
• Steam systems
• Diesel fuel systems
• Industrial and DIY projects (non-potable)