Union (O-Ring Type), Slip x Slip PVC Schedule 80 1/2" (897-005)

This 1/2" Schedule 80 PVC O-Ring Union provides a removable, pressure-tight connection point in a solvent-cemented Schedule 80 PVC piping system, allowing sections of pipe, valves, or equipment to be disconnected and reassembled without cutting into the solvent-welded line. Both slip socket tail piece ends accept standard 1/2" PVC pipe for permanent solvent cement joining into the surrounding piping system, while the union nut and O-ring face provide the removable, resealable interface at the union body itself.

The three-piece construction — two slip socket tail pieces and a threaded union nut — defines the operational logic of the 897-005. Each tail piece is solvent-cemented permanently into the piping on its side of the union; once cured, the tail pieces become fixed, integral components of the pipe run. The union nut threads over one tail piece and draws the two opposing faces together, compressing the O-ring between them to form a leak-free pressure seal. When the joint must be opened — for valve or equipment removal, pump servicing, filter replacement, or system modification — the nut backs off, the two faces separate, and the union opens cleanly. The surrounding solvent-welded piping on both sides remains undisturbed.

Selecting between the 897 and 898 series unions at 1/2" Schedule 80 requires understanding which system configuration each serves. The 897 Slip × Slip union belongs in solvent-welded PVC pipe systems — both tail pieces cement into plain pipe ends, and the union provides the single removable joint within an otherwise permanently joined system. The 898 FPT × FPT union belongs in fully threaded Schedule 80 systems — both tail pieces receive male-threaded nipples or pipe ends, and the union provides a removable joint within an all-threaded assembly. The O-ring seal mechanism, union nut, and disassembly procedure are identical between the two series; only the tail piece connection type changes. When the surrounding piping is solvent-welded PVC pipe, the 897 is the correct union; when the surrounding piping is threaded nipple-and-fitting construction, the 898 applies.

The O-ring seal at the union face is a critical performance feature. The elastomeric O-ring conforms precisely to both mating faces, producing a reliable, repeatable pressure seal that holds through repeated disassembly and reassembly cycles without degradation of the sealing surface. This repeatability is particularly important in applications with regular maintenance intervals — pump service schedules, filter change cycles, chemical dosing equipment calibration intervals, and seasonal system shutdowns where the union may be opened and closed multiple times per year. Unlike flat-face unions that rely on surface contact sealing, the O-ring provides consistent sealing performance independent of minor variations in make-up torque or face surface condition after cycling.

Manufactured in dark gray Schedule 80 PVC, this union delivers the increased wall thickness and mechanical strength required in industrial, chemical, and commercial pressure piping where Schedule 40 ratings are insufficient. PVC's broad chemical resistance covers acids, bases, salts, chlorine, and most common process fluids, providing long service life in corrosive environments where metal unions would corrode, seize, or contaminate the fluid stream. NSF/ANSI 61 listing confirms suitability for potable water contact.

Rated to 235 psi at 73°F (governed by the union nut and O-ring face assembly — lower than the individual tail piece socket pressure rating), this union handles standard pressure service across commercial and industrial small-bore Schedule 80 PVC applications. For the slip socket ends, clean and dry both pipe ends and socket interiors before application. Apply purple PVC primer to all mating surfaces, then apply a uniform coat of Schedule 80 PVC solvent cement to both the pipe end and socket interior before inserting. Hold each joint with a slight quarter-turn twist for 30 seconds and allow full cure time per the cement manufacturer's guidelines before pressurizing. The union nut should be tightened firmly by hand; use a strap wrench if additional torque is needed to seat the O-ring fully, but avoid mechanical over-torquing of the nut. Inspect the O-ring for cuts, swelling, chemical degradation, or deformation during each disassembly; replace before reassembly if any deterioration is visible. Apply published pressure derating factors for service temperatures above 73°F.

Specifications:

Industries & Applications:

• Industrial Process Piping — Installed adjacent to pumps, metering valves, chemical injection points, flow meters, and process instruments on 1/2" Schedule 80 PVC solvent-welded process lines where components must be periodically removed, calibrated, or replaced without cutting into the cemented piping; the slip socket tail pieces integrate directly into the solvent-welded system while the union nut provides the only removable joint in the assembly
• Chemical Dosing & Injection Systems — Provides removable joints at dosing pump outlets, injection quill connections, back-pressure valve assemblies, and chemical metering equipment on 1/2" Schedule 80 PVC chemical feed lines where regular equipment service, calibration intervals, and chemical compatibility checks require routine disconnection of components from the cemented piping system
• Water & Wastewater Treatment — Installs at chemical dosing equipment connections, sampling valve assemblies, instrument isolation points, and process equipment interfaces on 1/2" Schedule 80 PVC headers in municipal and industrial water treatment facilities where components must be removable for maintenance without disrupting the surrounding solvent-welded piping
• Commercial Plumbing — Creates serviceable break points in 1/2" Schedule 80 PVC solvent-welded building water supply and mechanical room piping at water heaters, pressure-reducing valve assemblies, backflow preventer connections, and equipment interfaces where future access for component replacement or system modification is a design requirement
• Irrigation & Agricultural Systems — Installs at chemical injection assemblies, filter housings, pump connections, and fertigation equipment interfaces on 1/2" Schedule 80 PVC solvent-welded irrigation branch lines where seasonal maintenance, winterization, and equipment service require routine disconnection from the cemented pipe system
• HVAC & Mechanical Systems — Provides maintainable connections at chemical feed equipment interfaces, pump connections, and instrument assembly points on 1/2" Schedule 80 PVC cooling tower makeup lines, treated water headers, and glycol system branches where the solvent-welded main line must remain intact while individual components are serviced or replaced