Flange (Loose Ring), Slip PVC Schedule 80 2-1/2" (854-025)

Blue Monster 76037 1-Step PVC Cement Clear (32OZ)

The 2-1/2" PVC Schedule 80 Loose Ring Slip Flange (854-025) delivers a field-adjustable, bolted flanged connection in Schedule 80 PVC piping systems where the rotatable backing ring of the van stone design provides a critical installation advantage over a fixed solid style flange. Manufactured from rigid gray PVC conforming to ASTM D1784 Cell Class 12454, this fitting is engineered for the pressure ratings, chemical resistance, and service demands of industrial, municipal, and commercial Schedule 80 pressure piping.

The loose ring (van stone) design consists of two components: the PVC flange hub with its solvent-weld slip socket end, and a separate backing ring that sits loosely behind the flange face and rotates freely around the hub. This free rotation is the defining practical advantage of the loose ring design—because the backing ring can spin independently of the pipe and hub, bolt-hole alignment to the mating flange is achieved by rotating the backing ring alone rather than rotating the entire pipe run. On pump connections, valve trains, equipment interfaces, and multi-flange assemblies where bolt holes must align across several faces simultaneously, this feature significantly reduces installation labor and eliminates the rotational pipe manipulation that fixed solid style flanges require during field installation.

The slip (socket) end accepts standard 2-1/2" Schedule 40 or Schedule 80 PVC pipe via solvent cement, creating a permanent, pressure-rated connection at the pipe-to-flange hub interface. Once solvent-welded, the hub is fixed to the pipe while the backing ring remains free to rotate for bolt-hole alignment at any point prior to bolt-up. After the flange gasket is positioned and the bolts are drawn down, the assembly delivers a fully rated, gasket-sealed flanged joint that can be unbolted and separated at any time for maintenance, equipment service, inspection, or component replacement—without cutting into the pipeline.

The 150 lb. ANSI/ASME B16.5 bolt pattern ensures direct compatibility with the full range of standard flanged pumps, valves, strainers, tanks, and equipment. The distinction between this 854-series slip flange and the 856-series spigot flange of the same size is the end connection geometry: the 854-025 slip end receives pipe into its socket hub via solvent weld, while the 856-025 spigot end inserts into a mating socket fitting as the male member of that joint. For systems where the flange connects to open pipe ends, the 854-025 slip is the standard choice. For prefabricated assemblies where the flange must insert into a socket-end fitting or valve body, refer to the 856-025 spigot variant.

Schedule 80 construction maintains consistent pressure class with surrounding Schedule 80 pipe and fittings throughout the system. Gray PVC delivers broad resistance to acids, bases, salts, and a wide range of industrial process fluids. For service temperatures above 140°F, consult CPVC Schedule 80 equivalents.

Specifications:

Industries & Applications:

• Chemical Processing — Field-installed flanged connections on chemical feed, dosing, and transfer line pump and valve interfaces where the rotatable backing ring simplifies bolt-hole alignment during installation
• Water & Wastewater Treatment — Pump isolation flange joints, strainer connections, and treatment equipment interfaces on 2-1/2" Schedule 80 process piping at pump stations and treatment facilities
• Industrial Manufacturing — Field-installed Schedule 80 piping systems and valve trains where the loose ring backing ring eliminates the need to rotate pipe runs for bolt-hole alignment at multiple flange faces
• Irrigation & Agriculture — Pump station flanged connections and filter manifold interfaces on 2-1/2" Schedule 80 commercial irrigation and fertigation systems requiring field-adjustable flanged joints
• Municipal Infrastructure — Lift station, water distribution, and treatment plant piping where loose ring flanges provide accessible, disconnectable connections with field bolt-hole alignment flexibility on 2-1/2" Schedule 80 mains
• Aquaculture & Aquatics — Recirculating system pump and filtration equipment flanged connections where field installation conditions require rotational backing ring adjustment for bolt-up
• HVAC & Plumbing — Commercial mechanical systems with Schedule 80 PVC piping requiring bolted flanged connections at equipment interfaces where field alignment flexibility is needed