Union (O-Ring Type), Slip x FPT PVC Schedule 80 1/2" (899-005)

The 899-005 is a 1/2" PVC Schedule 80 O-Ring Union with a slip (socket) end on one body and a female pipe thread (FPT) end on the other, designed to create a removable, pressure-rated disconnect point at the transition between a solvent-welded PVC pipe run and a female-threaded connection in the same piping system. Where the 897-series Slip × Slip union places a serviceable disconnect point within an all-solvent-weld pipe run, this mixed-connection union serves a distinct role: it bridges two different connection types — a permanent solvent-weld backbone on the slip side and a threaded interface on the FPT side — while preserving the full serviceability advantage that any O-ring union provides at the disconnect point.

Manufactured from dark gray PVC Schedule 80 compound, this union meets ASTM D2467 for the slip socket end and ASTM D2464 for the female pipe thread end, with NSF/ANSI 61 certification covering potable water contact applications. The heavier Schedule 80 wall thickness delivers the elevated pressure capacity and chemical resistance required in industrial process environments, chemical handling lines, and high-demand commercial systems — particularly relevant at the FPT threaded body, where the added wall stock reduces the risk of stress cracking at the thread roots under sustained pressure or thermal cycling.

The three-piece assembly consists of a slip socket body, an FPT threaded body, and a threaded collar nut that draws both bodies together against a precision O-ring seat. The slip body is permanently solvent-cemented to the PVC pipe run on its side of the union; the FPT body engages the male-threaded pipe, nipple, or fitting on its side. Once both bodies are installed at their respective connection points, the collar nut is hand-tightened and wrench-snugged to compress the O-ring and seal the union joint — no thread sealant or additional sealing compounds are required at the O-ring interface itself. When disconnection is needed, backing off the collar nut separates the two bodies cleanly, leaving both the solvent-welded pipe end and the threaded connection undisturbed and ready for reassembly once service is complete.

The practical value of the Slip × FPT union configuration over the Slip × Slip variant lies in its ability to serve as the transition union wherever a solvent-welded PVC system must connect to a threaded component — a ball valve, pump port, filter housing, instrument fitting, or any other male NPT-threaded element — while simultaneously providing a clean disconnect point at that same transition. Rather than requiring a separate solvent-welded union upstream of a threaded adapter at the component connection, the 899-005 accomplishes both the connection-type transition and the serviceable disconnect in a single three-piece fitting. At 1/2", this union is a common specification in chemical dosing lines, instrument isolation points, small-bore equipment connections, and filter bypass assemblies where solvent-weld pipe must interface with threaded components and periodic disconnection is a design requirement.

The slip body's solvent cement installation follows standard Schedule 80 procedures — clean, prime, and cement the mating pipe surface using a Schedule 80-compatible PVC cement per ASTM D2564. Allow full joint cure before pressurizing the system or engaging the union collar. The FPT body engages its mating male NPT threads with PTFE thread tape or an appropriate pipe thread sealant applied to the male threads before assembly. The governing pressure rating for this union assembly is determined by the FPT end as the more restrictive connection type; consult the manufacturer's published technical data for the confirmed working PSI at the 1/2" 899-005 before finalizing system design.

Specifications

Industries & Applications

• Chemical Handling & Process Piping — Transition disconnect points where a solvent-welded Schedule 80 PVC chemical transfer or reagent distribution line must connect to a threaded pump inlet, dosing valve, or injection fitting that requires periodic removal for service or replacement without disturbing the solvent-welded upstream pipe run
• Water Treatment & Purification — Serviceable connection points at filter housing inlets, UV system ports, and chemical feed equipment in municipal and industrial water treatment systems where the PVC pipe run is solvent-welded on the supply side and the equipment connection is male NPT threaded — and both the connection-type transition and the service disconnect must occur at the same point
• Industrial Process Piping — Instrument isolation unions, flow cell connection points, and inline sensor removal joints where a solvent-welded 1/2" Schedule 80 process line meets a threaded instrument or metering device body and periodic disconnection is built into the maintenance cycle
• Commercial Plumbing — Serviceable transition unions at water softener connections, chemical treatment equipment ports, and threaded valve inlets in commercial mechanical rooms where PVC is specified on the supply side and the downstream component is male NPT threaded
• Irrigation & Agriculture — Chemical injection pump isolation points and flow meter connection joints in Schedule 80-rated agricultural and turf irrigation systems where the PVC distribution line is solvent-welded and the injection or metering equipment presents a male NPT threaded inlet
• Laboratory & Analytical Systems — Removable transition joints for inline analytical instruments, reagent flow cells, and sampling devices in controlled-environment PVC piping where the pipe run is solvent-welded and the instrument connection is male NPT threaded — and clean reassembly after instrument removal is a routine requirement
• HVAC & Mechanical Systems — Serviceable disconnect points at chemical feed equipment inlets, corrosion-resistant auxiliary line connections, and cooling tower treatment injection ports where a solvent-welded PVC supply line must interface with a threaded equipment port and remain accessible for periodic maintenance