Sigma 818900649 Malleable Iron Pipe Cap 1-1/4 in 150 Lb

Product Description

The SIGMA 818900649 is a standard malleable iron pipe cap with a female NPT (FNPT) end connection, rated for 150 lb service. This fitting threads onto the end of an open pipe to seal it off, stopping flow at the terminus of a piping run. Built from black oxide-coated malleable iron, it is suited for general-purpose low-pressure piping systems handling water, air, steam, and other compatible media. Licensed plumbers and pipefitters install this fitting during new construction, retrofit work, and system modifications where a threaded pipe end requires permanent or semi-permanent closure.

The 818900649 is sized for 1-1/4 inch nominal pipe and carries a 150 lb pressure rating, making it appropriate for standard residential and light commercial piping applications. The FNPT thread pattern allows direct hand-start threading onto a male NPT pipe end, followed by tool tightening with pipe wrenches or strap wrenches. The black oxide finish provides a degree of corrosion resistance suitable for dry or moderate-exposure environments common in mechanical rooms, utility spaces, and above-grade piping installations.

Key Features

• 1-1/4 inch nominal size with FNPT thread for direct pipe connection
• 150 lb pressure rating for standard low-pressure service
• Malleable iron construction for strength and thread durability
• Black oxide finish for moderate corrosion resistance
• Seals open pipe ends in water, air, and steam piping systems

Compatibility

Designed as an OEM-style replacement and standard fitting for 1-1/4 inch nominal male NPT threaded pipe in 150 lb malleable iron piping systems.

Installation Notes

Installation is performed by a licensed plumber or pipefitter. Shut off system pressure and drain the line before threading on the cap. Apply an appropriate thread sealant or PTFE tape to the male pipe threads per local plumbing code requirements before tightening. Do not over-torque malleable iron fittings, as the material is strong but not ductile like steel pipe.

Technical Specifications

• Nominal Size: 1-1/4 inches
• End Style: FNPT (Female National Pipe Thread)
• Pressure Rating: 150 lb
• Material: Malleable Iron
• Finish: Black Oxide
• Figure Number: FIG 3124

Standard Information

• Brand: SIGMA
• Manufacturer Part Number: 818900649