Sigma 812508612 Fig 3463 Ground Joint Union 1 in Fnpt 150lb

Product Description

The SIGMA 812508612 is a FIG 3463 ground joint pipe union rated for 150 lb service in malleable iron with a black finish. Ground joint unions create a metal-to-metal seat at the union nut, allowing piping sections to be connected and disconnected without disturbing the rest of the system. The female national pipe taper (FNPT) end connections accept standard tapered pipe threads on both sides. At 1 inch nominal size, this union fits common distribution piping found in gas, steam, and water systems. Licensed plumbers and pipefitters install this fitting as part of maintenance access points or equipment connections where future serviceability is required.

This union is suited for residential and light commercial piping applications including gas distribution, low-pressure steam, and hydronic heating systems. The malleable iron construction handles the thermal cycling and mechanical stress common in these systems. The black finish is standard for gas piping installations. The ground joint design provides a reliable shutoff face that can be remade in the field without replacement hardware.

Key Features

• Ground joint metal-to-metal seat allows field-serviceable connections without sealant at the union face
• 150 lb pressure rating suitable for low-pressure gas, steam, and water service
• 1 inch nominal FNPT threading on both ends for standard tapered pipe thread connections
• Malleable iron construction resists impact and thermal stress in cycling systems
• Black finish meets standard requirements for gas piping identification

Compatibility

Designed as an OEM-style replacement fitting for 1 inch nominal malleable iron pipe union applications in 150 lb rated gas, steam, and water piping systems.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local plumbing and mechanical codes, including IPC and IFGC requirements. Shut off and depressurize the piping system completely before disassembling or installing any union fitting. Apply appropriate thread sealant to the FNPT pipe threads but not to the ground joint union face, which relies on metal-to-metal contact for its seal. Pressure-test the assembly per code requirements after installation before returning the system to service.

Technical Specifications

• Figure Number: FIG 3463
• Nominal Size: 1 inch
• End Style: FNPT (Female National Pipe Taper)
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Black
• Union Type: Ground Joint

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 812508612