Sigma 811087618 Reducing Coupling 1-1/4x1 in Fnpt 150lb

Product Description

The SIGMA 811087618 is a malleable iron reducing coupling designed for threaded pipe systems in plumbing, HVAC, and industrial piping applications. This FIG 3121R-pattern fitting connects pipes of two different diameters using female NPT (FNPT) threads on both ends, rated at 150 lb working pressure. The galvanized finish provides corrosion resistance for use in wet or moderately corrosive environments. At 1-1/4 x 1 inch nominal size, it is a standard trade size used to step down pipe diameter within a run. Licensed plumbers and pipefitters are the primary installers of this fitting in both new construction and retrofit work.

This reducing coupling is suited for residential and light commercial piping systems where a diameter reduction is needed inline without changing flow direction. Typical applications include water supply lines, gas distribution piping, compressed air systems, and general industrial fluid handling. The FNPT end style accepts standard tapered pipe threads on both ends, making it compatible with common black iron, galvanized steel, and brass pipe and fittings in 150 lb service.

Key Features

• Malleable iron construction for strength and machinability in threaded applications
• Galvanized finish resists corrosion in wet and outdoor-adjacent environments
• FNPT threads on both ends accept standard tapered pipe threads
• 150 lb pressure rating suitable for water, gas, and air service in typical trade applications
• FIG 3121R pattern conforms to standard reducing coupling dimensions
• 1-1/4 x 1 inch nominal sizing for common inline pipe reduction

Compatibility

Designed as an OEM-style replacement and standard trade fitting for 150 lb malleable iron threaded piping systems using 1-1/4 inch and 1 inch nominal pipe sizes with NPT threads.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable plumbing and mechanical codes such as the IPC or IFGC. Shut off and depressurize the pipe system completely before removing any existing fittings or installing this coupling. Apply an appropriate thread sealant or PTFE tape to the male pipe threads before assembly and tighten to a firm, wrench-tight connection. Do not over-torque, as malleable iron threads can crack under excessive force.

Technical Specifications

• Material: Malleable Iron
• Finish: Galvanized
• End Style: FNPT (Female National Pipe Taper) both ends
• Nominal Size: 1-1/4 x 1 inches
• Pressure Rating: 150 lb
• Figure Pattern: FIG 3121R

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 811087618