Union (O-Ring Type), FPT x FPT PVC Schedule 40 3" (498-030)

The 3" PVC Schedule 40 Union (O-Ring Type, FPT x FPT) provides a permanent yet re-joinable connection point in threaded PVC piping systems, allowing equipment, valves, or pipe sections to be removed and reinstalled without cutting into the line. Both end bodies accept male-threaded pipe or fittings via FPT (Female Pipe Thread) connections, making this union compatible with any standard 3" NPT-threaded PVC component.

What distinguishes the O-ring style union from a flat-face union is its sealing mechanism — a captured elastomeric O-ring seated in the union's mating face provides a consistent, compressive seal each time the union nut is tightened. This design is more forgiving across repeated assembly and disassembly cycles than flat-face unions, where surface condition and face-to-face contact are critical to maintaining a leak-free joint. For applications involving frequent maintenance access, seasonal disassembly, or equipment isolation, the O-ring union is generally the preferred specification.

At 3", this is a large-format union more commonly found in commercial mechanical systems, industrial process piping, and pump installations than in residential applications. Manufactured to ASTM D2466 standards and listed under NSF/ANSI 14, this fitting delivers the chemical resistance and structural integrity expected of Schedule 40 PVC across a wide range of service conditions.

Specifications:

Industries & Applications:

• Pump Systems & Mechanical Rooms — The most common application for unions at this size; installed on the suction and discharge sides of pumps to allow removal and servicing without disturbing the surrounding piping
• Chemical Processing — Provides a re-joinable isolation point in chemical feed, transfer, and distribution lines where PVC's broad chemical resistance is required and periodic maintenance access is expected
• Municipal Water & Wastewater — Used at valves, meters, and treatment equipment connections in pump stations, treatment facilities, and distribution infrastructure requiring regular service intervals
• Commercial Plumbing — Applied at equipment connections, water heaters, backflow preventers, and filtration systems in commercial buildings where threaded PVC connections are specified
• Irrigation & Agricultural — Installed at pump discharge points, filter stations, and fertigation equipment in large-scale irrigation systems requiring seasonal teardown or maintenance access
• Industrial Manufacturing — Provides isolation and access points in process piping where equipment must be regularly removed, cleaned, or replaced without cutting into permanent pipe runs
• Aquaculture & Water Treatment — Allows disassembly of filtration components, UV systems, and treatment equipment in recirculating systems where maintenance frequency is high