Union (O-Ring Type), FPT x FPT PVC Schedule 80 1-1/2" (898-015)

The 898-015 is a 1-1/2" Schedule 80 PVC Union with an O-ring seal, featuring Female Pipe Thread (FPT) connections on both ends. This is a fully threaded union — both the inlet and outlet connect to male-threaded (MPT) pipe ends or fitting ports via NPT threads, making it a solvent-free installation on both sides. Like all union fittings, the 898-015 exists to make a pressure piping system serviceable: it allows the line to be broken apart at that point for equipment removal, valve replacement, pump service, or system modification without cutting pipe, disturbing cemented joints, or decommissioning the surrounding assembly.

The FPT x FPT configuration makes this union particularly well suited for all-threaded systems and equipment connections where solvent cement is not used — or cannot be used — on either side of the union. Where the Slip x FPT version (899-015) bridges a cemented pipe run into a threaded port, the FPT x FPT union sits entirely within a threaded assembly, connecting two male-threaded pipe ends or equipment ports with a disassemblable joint in between. This is common in systems built around threaded PVC pipe, equipment with MPT inlet and outlet ports, and installations where future disassembly is a design requirement on both sides of the union.

The O-ring seal design provides a superior pressure seal compared to traditional flat-faced unions. Rather than relying on face-to-face contact alone to hold pressure at the union joint, the O-ring compresses into a seated groove as the union nut is tightened, creating a reliable, leak-resistant seal that performs consistently under sustained operating pressure and thermal cycling. This makes the O-ring type union the preferred specification over flat-face designs in chemical processing, water treatment, and industrial fluid handling applications where joint integrity over the full service life of the system is non-negotiable.

Thread sealant tape (PTFE) or pipe dope rated for PVC service should be applied to all male threads before assembly on both ends. The union nut should be hand-tightened and finished with a strap wrench — do not use metal pipe wrenches on PVC union bodies or nuts, as point loading from metal jaw wrenches can crack the fitting body or distort the union nut seating surface.

Specifications:

⚠️ Note: Apply PTFE thread tape or PVC-compatible pipe dope to all male threads before assembly. Tighten the union nut with a strap wrench only — do not use metal jaw wrenches on PVC union bodies. Pressure ratings decrease at elevated temperatures; consult manufacturer derating tables for high-temperature service.

Industries & Applications:

• Chemical Processing — Provides a disassemblable joint in fully threaded chemical feed and dosing lines, allowing pumps, metering equipment, and inline instruments to be removed for calibration or maintenance without disturbing the surrounding pipe assembly
• Water & Wastewater Treatment — Used at pump inlets and outlets, filter connections, and instrumentation ports in treatment plant piping where both sides of the union connect to male-threaded equipment or fittings and periodic disassembly is required
• Industrial Plumbing — Installed in all-threaded PVC systems at service points — valve connections, strainer ports, and equipment tie-ins — where the union provides the only break point in an otherwise permanent assembly
• Irrigation & Agricultural Systems — Used in threaded valve assemblies and pump connections on pressurized irrigation systems where seasonal service or equipment replacement must be performed without cutting into the line
• Commercial Mechanical Systems — Connects threaded PVC pipe runs to equipment ports on fluid handling systems in commercial buildings where periodic maintenance access is a design requirement
• Aquaculture & Commercial Pool/Spa — Applied in fully threaded equipment connections on recirculating water systems where pump heads, heaters, and filtration equipment must be periodically removed without pipe modification