Sigma 811081009 Pipe Coupling 1-1/2 in Fnpt 150 Lb Galvanized

Product Description

The SIGMA 811081009 is a FIG 3121 full-coupling fitting designed for threaded pipe connections in plumbing, HVAC, and light industrial piping systems. Built from galvanized malleable iron, this coupling accepts a 1-1/2 inch nominal pipe size with female NPT (FNPT) threads on both ends. The 150 lb pressure class rating makes it appropriate for low-pressure steam, water, and gas distribution lines. Licensed plumbers and pipefitters install this type of fitting as a straight connector between two threaded pipe sections. The galvanized finish provides corrosion resistance in exposed or damp environments.

This coupling is suited for residential and commercial piping installations where a threaded inline connection is required. Typical applications include water distribution, hydronic heating supply and return lines, compressed air systems, and natural gas branch lines within rated pressure limits. The FNPT end style on both sides allows direct threading onto standard NPT-threaded pipe or nipples without adapters.

Key Features

• FIG 3121 full coupling profile with FNPT threads on both ends
• 1-1/2 inch nominal pipe size for standard threaded pipe connections
• 150 lb pressure class rating suitable for low-pressure water, steam, and gas service
• Malleable iron construction for strength and resistance to impact in threaded assemblies
• Galvanized finish for corrosion resistance in wet or exposed installations

Compatibility

Designed as an OEM-style threaded fitting for use with standard 1-1/2 inch NPT-threaded pipe in malleable iron piping systems rated to 150 lb service class.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable IPC or IFGC code requirements for the service type. Shut off and depressurize the line completely before disassembly or fitting installation. Apply an appropriate thread sealant or PTFE tape to male threads before assembly, and tighten to hand-tight plus the number of turns appropriate for the pipe size per standard practice. Do not over-torque malleable iron fittings, as the material can crack under excessive force.

Technical Specifications

• Figure Number: FIG 3121
• Nominal Pipe Size: 1-1/2 inches
• End Style: FNPT (Female National Pipe Thread) both ends
• Pressure Class: 150 lb
• Material: Malleable Iron
• Finish: Galvanized

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 811081009