Sigma 819908807 Hex Head Pipe Bushing 3x4 in 150lb Galvanized

Product Description

The SIGMA 819908807 is a hex head pipe bushing designed to reduce a 4-inch female NPT fitting down to a 3-inch male NPT connection. Built from malleable iron with a galvanized finish, this bushing delivers corrosion resistance and mechanical durability in piping systems that see moisture, thermal cycling, or outdoor exposure. The hex head design allows standard wrench engagement for secure installation and controlled makeup torque. Rated at 150 lb, it is appropriate for low-pressure steam, water, gas, and air distribution lines in commercial and industrial piping assemblies. Licensed plumbers and pipefitters install this type of fitting as part of threaded pipe system assembly and modification work.

This bushing is suited for use in residential and light commercial plumbing, HVAC piping, compressed air distribution, and general-purpose pipe systems where a 4-inch to 3-inch threaded reduction is required. The MNPT x FNPT end configuration threads directly into a female pipe fitting or valve on the larger end while accepting a male-threaded pipe or fitting on the smaller end. It is a standard FIG 3383 style fitting commonly specified in threaded piping takeoffs and system modifications.

Key Features

• Hex head profile accepts standard pipe wrenches and open-end wrenches for positive makeup
• Malleable iron construction provides strength and resistance to mechanical shock in threaded assemblies
• Galvanized finish adds corrosion protection for wet or outdoor service environments
• 150 lb pressure rating suitable for low-pressure water, air, gas, and steam service
• 3 x 4 inch nominal size with MNPT x FNPT end style for direct in-line threaded reduction
• FIG 3383 designation for straightforward cross-reference with standard piping schedules

Compatibility

Designed as an OEM-style threaded fitting replacement for standard 150 lb malleable iron pipe systems requiring a 4-inch to 3-inch NPT reducing bushing.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable plumbing and mechanical codes, including IPC and IFGC requirements where applicable. Shut off and depressurize the piping system completely before removing or installing any threaded fitting. Apply an appropriate thread sealant or PTFE tape to the male threads before makeup. Do not over-tighten; excess force on malleable iron fittings can crack the casting.

Technical Specifications

• Nominal Size: 3 x 4 inches
• End Style: MNPT x FNPT
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Galvanized
• Figure Number: FIG 3383

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 819908807