Sigma 811086008 Reducing Coupling 3/4x1/2 in Fnpt 150 Lb

Product Description

The SIGMA 811086008 is a FIG 3121R reducing coupling designed to connect threaded pipe sections of different diameters in low-pressure piping systems. Manufactured from malleable iron with a galvanized finish, this fitting transitions from a 3/4-inch nominal pipe to a 1/2-inch nominal pipe using female NPT (FNPT) threads on both ends. Rated at 150 lb, it meets standard pressure ratings for commercial and residential piping installations. Plumbers and pipefitters install this fitting where a threaded reduction is needed without the use of a separate bushing or union. The galvanized coating provides corrosion resistance suitable for water and gas distribution lines.

This reducing coupling is used in residential and light commercial plumbing, gas distribution, and mechanical piping systems. It is well suited for applications requiring a direct inline reduction between 3/4-inch and 1/2-inch threaded pipe runs. Typical install scenarios include supply line transitions, branch takeoffs, and utility connections where malleable iron fittings are specified. It is appropriate for use with black or galvanized pipe in steam, water, air, and gas service within the fitting pressure rating.

Key Features

• Reduces from 3/4-inch to 1/2-inch nominal pipe size in a single inline fitting
• FNPT threads on both ends for standard threaded pipe connections
• 150 lb pressure-rated malleable iron construction
• Galvanized finish for corrosion resistance in wet or outdoor environments
• FIG 3121R pattern — a widely recognized standard reducing coupling configuration

Compatibility

Designed as an OEM-style replacement and standard-use fitting for 3/4-inch by 1/2-inch threaded malleable iron piping systems rated at 150 lb class.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local mechanical and plumbing codes. Shut off and depressurize the piping system completely before removing or installing any threaded fittings. Apply an approved pipe thread sealant or PTFE tape to male threads before assembly to ensure a leak-free joint. Do not overtighten, as malleable iron threads can crack under excessive torque.

Technical Specifications

• Nominal Size: 3/4 x 1/2 inches
• End Style: FNPT (Female National Pipe Thread) both ends
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Galvanized
• Figure Number: FIG 3121R

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 811086008