Merit Brass K619-48 Pipe Locknut 3 in 316 Ss 150 Psi

Product Description

The MERIT BRASS K619-48 is a 3-inch pipe locknut machined from 316 stainless steel for corrosion-resistant performance in demanding piping applications. It features a female national pipe straight locknut (FNPSL) end connection and is pressure-rated at 150 psi. At 4-9/64 inches in length, this locknut is sized for securing fittings, conduit, or threaded pipe through panels, bulkheads, and enclosures where a reliable mechanical hold is required. Licensed plumbers and pipefitters install this hardware as part of system assembly wherever a locknut is specified on the job.

This locknut is suited for use in commercial and industrial piping systems where 316 stainless steel is specified for its resistance to chlorides, acids, and high-moisture environments. Typical applications include process piping, marine installations, food-service plumbing, and chemical handling systems. The FNPSL thread form provides a straight-threaded mechanical connection designed to secure and hold fittings in place without sealing pressure on its own. This part ships individually and is available in single-unit quantities, making it practical for both service calls and new construction.

Key Features

• 316 stainless steel construction for superior corrosion resistance in harsh and wet environments
• 150 psi pressure rating suitable for standard commercial and light industrial piping service
• FNPSL end connection provides straight-threaded engagement for mechanical locknut duty
• 3-inch fitting size accommodates large-diameter pipe and bulkhead installations
• 4-9/64 inch length provides adequate thread engagement for secure panel and fixture mounting

Compatibility

Designed as an OEM-style replacement or new-installation locknut for 3-inch threaded pipe systems requiring 316 stainless steel FNPSL hardware at 150 psi service ratings.

Installation Notes

Installation is typically performed by a licensed plumber or pipefitter following applicable IPC and ASME B31 piping codes. Shut off and depressurize the system completely before removing or installing any threaded pipe hardware. Use appropriate pipe wrenches sized for 3-inch fittings and avoid over-torquing, which can damage threads or deform thin panel material. Because the FNPSL connection is a straight mechanical thread and not a pressure-sealing taper thread, a separate sealing fitting or gasket must be used where fluid containment is required.