1/8 inch Square Head Black Cast Iron Plug

1/8" Black Cast Iron Square Head Plug – For Sealing Threaded Pipe Ends

The 1/8" Black Cast Iron Plug is manufactured to seal the ends of threaded pipe runs in low-pressure piping systems. Its square head design allows for easy installation and removal using standard wrenches, and the robust cast iron construction offers strength and longevity in non-potable water, gas, or air systems.

Engineered to meet ANSI/ASME B16.3 and ASTM A-126 Class B standards, this plug is compatible with Schedule 40 and Schedule 80 black iron or steel piping. It is suitable for applications that do not require corrosion resistance, such as heating lines, industrial air systems, or fire sprinkler piping.

Performance Features

• Material: Cast iron, black finish for use in non-corrosive environments
• Connection: Male NPT (National Pipe Thread), tapered for leak resistance
• Head Type: Square head for wrench-tight installation
• Size: 1/8 inch nominal pipe size
• Operating Pressure: Rated for up to 150 psi in non-shock conditions (varies by system configuration)

Common Applications

• Sealing unused pipe outlets or ends in low-pressure black iron piping systems
• Closure point for maintenance access or system modifications
• Used in hydronic heating, compressed air lines, or fuel oil systems where cast iron is permitted

Installation Guidelines

Apply a suitable thread sealant (pipe dope or PTFE tape) to male threads before tightening to ensure a leak-resistant joint. Avoid overtightening to prevent thread distortion. Installation should follow local code requirements and ANSI/ASME guidelines for pipe fittings.

Additional Notes

Cast iron plugs are not suitable for potable water systems or applications requiring corrosion resistance. For such environments, consider malleable iron or brass alternatives rated for those conditions.