Sigma 813509411 Ground Joint Pipe Union 2-1/2 in 150 Lb

Product Description

The SIGMA 813509411 is a FIG 3463 ground joint pipe union rated at 150 lb and sized for 2-1/2 inch nominal pipe. Ground joint unions use a machined brass or iron seat at the center nut to create a leak-resistant metal-to-metal seal, making them a reliable choice for threaded pipe systems that require periodic disassembly. The body is malleable iron with a galvanized finish for corrosion resistance. Both ends are female NPT (FNPT), allowing straightforward connection to standard threaded pipe. Plumbers and pipefitters install this fitting where sections of pipe must be disconnected for service or replacement without cutting.

This union is suited for residential and commercial plumbing, gas distribution, steam, and general industrial piping applications where 150 lb rated malleable iron fittings are specified. The galvanized finish makes it appropriate for wet or mildly corrosive environments. It is commonly installed in mechanical rooms, boiler rooms, and utility piping runs where routine access to flanged or threaded connections is required.

Key Features

• 150 lb pressure rating for standard service plumbing and gas piping
• Ground joint design provides a reliable metal-to-metal seal at the union nut
• Malleable iron construction for durability in threaded piping systems
• Galvanized finish resists corrosion in wet and exposed environments
• FNPT ends on both sides connect to standard NPT-threaded pipe and fittings
• 2-1/2 inch nominal size suitable for larger-diameter piping runs

Compatibility

Designed as an OEM-style replacement or new-installation fitting for 2-1/2 inch nominal NPT threaded pipe systems using 150 lb malleable iron fittings.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable codes including the IPC and IFGC where gas service is involved. Depressurize and drain the pipe system fully before disassembly or installation. Apply thread sealant or PTFE tape to all NPT threads before assembly. Tighten the union nut to a snug, wrench-tight fit at the ground joint seat — do not overtighten, as this can damage the seating surface.

Technical Specifications

• Figure Number: FIG 3463
• Nominal Size: 2-1/2 inches
• End Style: FNPT (Female National Pipe Thread)
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Galvanized

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 813509411