Sigma 811080407 Fig 3121 Pipe Coupling 3/4 in Fnpt 150 Lb

Product Description

The SIGMA 811080407 is a FIG 3121 malleable iron pipe coupling designed for joining two sections of threaded pipe in low-pressure piping systems. Finished with a hot-dip galvanized coating, this coupling resists corrosion in wet and exposed environments. The female NPT (FNPT) end style on both sides accepts standard tapered pipe threads for a secure, leak-resistant connection. Rated at 150 lb, it is suited for steam, water, oil, and gas service in commercial and industrial piping applications. Licensed plumbers and pipefitters are the primary installers of this fitting.

This coupling is used in residential and commercial plumbing, HVAC hydronic systems, and industrial pipe networks where 3/4 inch threaded connections are required. The galvanized finish makes it appropriate for outdoor, underground adjacent, or otherwise corrosion-prone environments. It follows FIG 3121 dimensional standards, making it a direct fit in systems built to that specification. The 150 lb pressure class is the standard rating for general-service threaded malleable iron fittings across a wide range of piping applications.

Key Features

• Malleable iron construction provides strength and impact resistance in threaded piping systems
• Galvanized finish offers corrosion protection for wet and exposed installations
• FNPT end style on both ends accepts standard tapered pipe threads
• 150 lb pressure class rated for steam, water, oil, and gas service
• FIG 3121 pattern for dimensional conformance with standard threaded fitting systems
• 3/4 inch nominal pipe size for common residential and commercial piping applications

Compatibility

Designed as an OEM-style replacement and general-service threaded fitting for 3/4 inch nominal pipe systems using standard NPT threaded connections and rated for 150 lb service class.

Installation Notes

Installation should be performed by a licensed plumber or qualified pipefitter in accordance with applicable local plumbing codes and ASME B16.3 standards for malleable iron threaded fittings. Shut off and depressurize the piping system completely before making or breaking any threaded connections. Apply an appropriate thread sealant or PTFE tape to male threads before assembly. Do not over-torque the fitting, as malleable iron can crack under excessive force.

Technical Specifications

• Nominal Pipe Size: 3/4 inch
• End Style: FNPT (Female National Pipe Taper) both ends
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Galvanized
• Figure Number: FIG 3121

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 811080407