Plug, MPT PVC Schedule 80 1/4" (850-002)

This 1/4" Schedule 80 PVC Threaded Plug (MPT) provides a clean, pressure-rated closure for any standard 1/4" female NPT-threaded port, fitting outlet, or equipment connection in industrial, chemical, and commercial piping systems. Constructed in dark gray Schedule 80 PVC, it delivers the elevated wall thickness and pressure capacity required in demanding installations where a reliable, corrosion-resistant threaded closure is needed at small-bore female-threaded ports — including instrument taps, pressure gauge connections, sampling points, and chemical injection fittings that are integral to Schedule 80 process and distribution assemblies.

The male pipe thread (MPT) exterior is cut to NPT tapered thread standards, threading directly into any 1/4" female NPT port — including tee branch outlets, cross ports, manifold bodies, valve bodies, instrument connections, and equipment tap fittings — to form a pressure-tight mechanical closure when made up with thread sealant or PTFE tape. At 1/4", this plug is most frequently encountered closing out instrument ports, gauge tap connections, pressure test fittings, and small-bore chemical injection points on larger Schedule 80 assemblies where 1/4" FPT ports are standard for instrument and sampling connections regardless of the mainline pipe diameter. The MPT plug threads into a female port — it should not be confused with the FPT cap (848 series), which threads over a male pipe end, the spigot plug (849 series), which cements into a socket hub, or the slip cap (847 series), which sockets over a pipe end.

Rated to approximately 970 psi at 73°F, this plug is well-suited for demanding pressure service across a broad range of industrial, chemical, and commercial fluid handling applications. Its PVC composition provides excellent resistance to acids, bases, salts, and chlorinated water, making it a durable long-term closure in corrosive environments where metal plugs would degrade, seize in the threads, or introduce contamination into the system fluid. NSF/ANSI 61 listing confirms suitability for potable water contact, including use in drinking water distribution and treatment systems.

Install using a quality pipe thread sealant or PTFE tape on the MPT threads before engagement. At 1/4", the small thread engagement depth requires particular care to avoid cross-threading — start threads by hand and confirm square engagement before applying torque. Avoid over-torquing — PVC threads require hand-tight plus one to two turns; excessive force can crack the plug body or damage the receiving female threads at this small diameter. If used as a temporary closure during system testing or phased construction, inspect the plug and threads before reinstalling or returning the system to service. Derate pressure ratings for elevated temperatures per published derating curves.

Specifications:

Industries & Applications:

• Industrial Process Piping — Closes unused 1/4" female-threaded instrument ports, pressure gauge taps, sampling connections, and spare manifold outlets on Schedule 80 chemical processing, water treatment, and manufacturing assemblies where small-bore threaded closures are required at high-pressure instrument and monitoring connection points
• Chemical Handling — Provides a corrosion-resistant threaded closure for unused 1/4" female ports on Schedule 80 chemical distribution manifolds, metering pump assemblies, injection line headers, and dosing system components conveying acids, caustics, fertilizer solutions, and other fluids incompatible with metal plugs that may corrode, seize, or leach contaminants into the system
• Water Treatment & Aquaculture — Used to close spare 1/4" instrument ports, unused pressure tap connections, and open female-threaded sampling points on recirculating system headers, chemical dosing manifolds, and treatment equipment assemblies where NSF/ANSI 61 compliance and Schedule 80 chemical resistance are required at small-bore monitoring connections
• Commercial Plumbing — Caps unused 1/4" female-threaded gauge taps, pressure test ports, and instrument connections on valve manifolds, backflow preventer assemblies, and pressurized water supply systems in high-pressure or exposed commercial building installations
• Irrigation & Water Distribution — Seals unused 1/4" female-threaded instrument and monitoring ports on filter housings, pressure regulator assemblies, and valve station manifolds in high-pressure agricultural and municipal irrigation systems where Schedule 80 pressure ratings are specified at instrument connection points
• HVAC & Mechanical Systems — Caps unused 1/4" female-threaded gauge ports, drain taps, and instrument connections on Schedule 80 cooling tower chemical feed lines, chilled water monitoring manifolds, and chemically treated water system assemblies requiring elevated pressure ratings at small-bore instrument closure points