Flange (Loose Ring), PVC Schedule 80 10" (856-100FT)

The 10" PVC Schedule 80 Loose Ring Flange (856-100FT) is a heavy-duty, two-piece Van Stone-style flange assembly designed for large-diameter piping systems that require bolted, removable connections in corrosive, high-purity, or chemically aggressive service environments. The assembly pairs a stub end — solvent welded permanently onto the pipe — with a free-rotating backing ring that spins independently until the bolts are drawn down, allowing full 360° bolt hole alignment to any mating flange without twisting, repositioning, or stressing the pipeline upstream.

At 10", the practical value of the loose ring design is immediately apparent. Large-diameter pipe is heavy, rigid, and difficult to maneuver in confined mechanical rooms, pump vaults, and equipment bays. Fixed flanges require the pipe run to be pre-oriented so the bolt holes align with the mating flange — a demanding requirement when the pipe is already in position and the mating flange orientation is fixed by a pump, valve, or piece of inline equipment. The loose ring flange eliminates this constraint entirely: weld the stub end to the pipe, position the run, then simply rotate the backing ring until the bolt holes line up and draw the bolts down. The assembly is fully aligned and sealed without ever repositioning the pipe.

The all-PVC wetted path eliminates galvanic corrosion, metal ion contamination, and the dezincification and rust concerns associated with metal flanges in chemically treated, high-purity, or saline water systems. Every surface in contact with the process fluid is PVC — chemically inert across the broad range of acids, caustics, oxidizers, and industrial process fluids that define the environments where Schedule 80 PVC flanged systems are most commonly specified. Schedule 80 construction provides the structural depth and pressure margins required beyond Schedule 40 limits, and the flat face flange face mates correctly with full-face gaskets to protect the sealing surface under bolt load at this diameter.

Drilled to the 150 lb. ANSI/ASME B16.5 pattern, the 856-100FT is dimensionally compatible with standard metal and PVC companion flanges, pump discharge flanges, butterfly valve wafer ends, and inline equipment across municipal, industrial, and chemical process applications at 10". At this size, the ANSI 150 drilling pattern is effectively universal for standard-pressure PVC flanged piping — ensuring that the 856-100FT mates directly to the full range of valves, pumps, meters, and equipment flanges specified to that standard without custom drilling or adapter plates.

Specifications:

Industries & Applications:

Chemical Processing & Industrial Fluid Handling Large-diameter chemical transfer headers at 10" require flanged connections that can be broken and reassembled for pump maintenance, heat exchanger cleaning, inline filter replacement, and periodic process equipment changeouts. The all-PVC wetted path of the 856-100FT resists the concentrated acids, caustic solutions, and oxidizing process fluids that corrode metal flanges at the sealing face over time, while the rotating backing ring eliminates the alignment difficulty that comes with heavy 10" chemical pipe runs in confined processing structures. The loose ring design is particularly valuable in chemical plants where flanged connections are broken and reassembled on defined maintenance schedules — the rotating ring dramatically reduces reassembly time compared to fixed flanges that require the pipe run to be physically repositioned to realign bolt holes.

Municipal Water & Wastewater Treatment Pump station headers, primary clarifier inlet and outlet connections, filter influent and effluent piping, and chemical dosing system mains in water and wastewater treatment plants are standard environments for 10" flanged PVC. The loose ring design is especially practical at pump flanges and valve body connections where bolt circle alignment to a fixed equipment flange would otherwise require precise pipe pre-positioning during installation. The NSF/ANSI 61 certification confirms suitability for potable water contact in municipal water treatment and distribution applications, and the ANSI 150 drilling pattern ensures direct dimensional compatibility with the pumps, butterfly valves, and gate valves standard to municipal water infrastructure.

Industrial Cooling & Process Water Systems Cooling tower distribution mains, chiller plant supply and return headers, and closed-loop recirculating cooling systems use Schedule 80 PVC flanges at 10" where chemical treatment — biocides, scale inhibitors, and corrosion control compounds — makes metallic piping unsuitable for the long term. Flanged connections at heat exchangers, strainers, balancing valves, and cooling tower cells allow major components to be isolated and removed for seasonal maintenance and equipment replacement without cutting the distribution main. The loose ring simplifies reassembly at equipment flanges with fixed bolt circle orientations after maintenance is complete.

Power Generation & High-Purity Utility Piping Service water systems, demineralized water distribution headers, and condensate polishing loops in power generation facilities use 10" Schedule 80 PVC flanges where high-purity water must be conveyed without metal ion contribution to the process stream. Flanged connections at ion exchange vessels, ultrafiltration skids, and chemical injection points allow process equipment to be isolated and replaced during scheduled outages without cutting the primary distribution header. The loose ring design is practical in power plant piping where equipment flanges have fixed orientations determined by equipment layout, and bolt hole alignment on large-diameter flanges must be achieved without repositioning heavy pipe runs.

Large-Scale Agricultural & Industrial Irrigation Pump station discharge headers at 10" in large agricultural irrigation systems — center pivot supply mains, canal pump stations, and large-scale drip system primary headers — connect to downstream distribution piping via flanged joints at pump outlets, filter stations, and mainline isolation valves. The loose ring flange is especially practical at pump discharge connections where the bolt circle orientation must match the fixed pump flange without repositioning the discharge header, and where the flanged joint will be broken periodically for pump impeller inspection, mechanical seal replacement, and seasonal maintenance.

Mining & Mineral Processing Process water mains, slurry transport headers, and leach field distribution manifolds at 10" in mining and mineral processing operations use Schedule 80 PVC flanges where the highly acidic or alkaline process solutions involved rapidly degrade carbon steel and ductile iron. Flanged connections at pump stations, settling tank connections, and inline treatment equipment allow sections to be isolated and replaced as chemical attack or wear dictates. The loose ring design simplifies maintenance at remote pump stations and processing structures where working space is constrained and bolt hole alignment on large flanges must be achieved efficiently.