CPVC Backing Ring
A CPVC Backing Ring is a mechanical component used in piping systems, typically made of Chlorinated Polyvinyl Chloride (CPVC), that provides support and reinforcement to flanged joints. Its main purpose is to prevent flange deformation, ensure proper gasket compression, and maintain a leak-free seal when bolts are tightened. Backing rings are especially useful in high-pressure or high-temperature applications where CPVC pipes and fittings are joined using flanges.
The CPVC Backing Ring is a precision-molded component used in conjunction with stub ends or flanged joints in piping systems to ensure a secure, even distribution of clamping force and effective sealing. These backing rings offer excellent resistance to corrosion, high temperatures, and chemical exposure. They are commonly used in industrial, chemical, and water treatment applications where flanged connections are required for easy disassembly and maintenance.
- Chemical Resistance
- Low Maintenance Requirement
- Low Thermal Conductivity
- Long Service Life
- Easy Installation
- Corrosion Resistance
CPVC Backing Ring Details
- OD – Outer Diameter
- PCD – Pitch Circle Diameter (for flange bolt circle)
- D – Outside Diameter (often used interchangeably with OD)
- Holes × Dia – Number of Bolt Holes × Diameter of Each Hole
| Nominal Pipe | Pipe OD (mm) | Ring OD D (mm) | Bolt Circle PCD (mm) | Holes × Dia (mm) |
| ½″ (DN15) | ~21.3 | ~89 | ~60.3 | 4 × ~16 |
| ¾″ (DN20) | ~26.7 | ~98.6 | ~69.8 | 4 × ~16 |
| 1″ (DN25) | ~33.4 | ~108 | ~79.4 | 4 × ~16 |
| 1¼″ (DN32) | ~42.2 | ~117.3 | ~88.9 | 4 × ~16 |
| 1½″ (DN40) | ~48.3 | ~127 | ~98.5 | 4 × ~16 |
| 2″ (DN50) | ~60.3 | ~152.4 | ~120.6 | 4 × ~19 |
| 2½″ (DN65) | ~73.0 | ~177.8 | ~139.7 | 4 × ~19 |
| 3″ (DN80) | ~88.9 | ~190.5 | ~152.4 | 4 × ~19 |
| 4″ (DN100) | ~114.3 | ~228.6 | ~190.5 | 8 × ~19 |
| Parameter | Details |
| Product Type | Backing Ring / Flange Support Ring |
| Function | Provides mechanical support for flanged joints |
| Material | CPVC (Chlorinated Polyvinyl Chloride) |
| Size Range | DN 15 – DN 200 (½″ to 8″) |
| Pressure Rating | Up to PN 10 / 10 bar (depends on flange class) |
| Temperature Range | 0°C to 90°C |
| Standard Compatibility | ASTM, DIN, ANSI (Class 150), BS standards |
| Connection Type | Used with stub end + bolt/nut flange system |
| Bolt Holes | As per flange drilling standards (ANSI/DIN) |
| Installation | Slip-on over stub end, bolted to mating flange |
| Base Material | CPVC thermoplastic |
| Specific Gravity | ~1.45 – 1.55 |
| Tensile Strength | ~7000 psi |
| Flexural Strength | ~11,000 – 13,000 psi |
| Impact Strength | Good impact resistance |
| Thermal Conductivity | Low (insulating material) |
| Corrosion Resistance | Excellent (no rust or scaling) |
| Chemical Resistance | Resistant to acids, alkalis, salts |
| Shape | Circular ring with bolt holes |
| Design | Flat face with precision-drilled holes |
| Weight | Lightweight compared to metal backing rings |
| Surface Finish | Smooth, non-corrosive surface |
| Color | Grey / ivory (typical CPVC color) |
| Strength | Provides rigidity to plastic flange joints |
| Durability | Long service life under proper conditions |
High Chemical Resistance: Inert to a wide range of corrosive chemicals, making it ideal for aggressive environments.
Thermal Stability: Can withstand continuous operating temperatures up to 93°C (200°F).
Corrosion-Free: Unlike metal rings, CPVC backing rings will not rust or corrode, even in moist or chemically reactive conditions.
Lightweight and Durable: Offers mechanical strength while being easier to handle and install compared to metal alternatives.
Smooth Surface Finish: Provides consistent pressure distribution and sealing with minimal surface friction.
UV and Weather Resistant: Suitable for use in both indoor and protected outdoor installations.
Compatible Design: Works seamlessly with CPVC stub ends and flanged fittings for reliable joint assembly.
| Nominal Size (DN / Inch) | Pressure Rating at 23°C (73°F) | Pressure Class |
| ½” – 2″ (DN15 – DN50) | Up to 16 bar | PN16 |
| 2½” – 4″ (DN65 – DN100) | Up to 16 bar | PN16 |
| 5″ – 8″ (DN125 – DN200) | Up to 10 – 16 bar | PN10 / PN16 |
| 10″ – 12″ (DN250 – DN300) | Up to 10 bar | PN10 |
| Above 12″ (DN350+) | 6 – 10 bar (design dependent) | PN6 / PN10 |
Temperature Derating (Typical for CPVC)
| Temperature | Pressure Capacity |
| 23°C | 100% rated pressure |
| 40°C | ~75% of rated pressure |
| 60°C | ~50% of rated pressure |
| 80°C | ~25–30% of rated pressure |
Custom Product Manufacturing Available
If you are searching for customized product designs that meet your requirements, don’t worry. Petron Thermoplast also offers custom product manufacturing services to meet the unique needs of various industries. Work with our expert engineers to create custom designs suited for your application.
Benefits of Using CPVC Backing Ring
High Corrosion Resistance
CPVC backing rings are highly resistant to chemicals, acids, and alkalis, making them ideal for corrosive environments.
Strong Flange Support
They provide strong mechanical support to CPVC flanges, helping maintain proper alignment and preventing flange damage.
Leak-Free Sealing
By ensuring uniform gasket compression, backing rings help create a tight and reliable seal at flange joints.
Lightweight Material
CPVC backing rings are much lighter than metal rings, making installation and handling easier.
High Temperature Resistance
CPVC can handle higher temperatures compared to standard PVC, making it suitable for hot water and industrial applications.
Excellent Chemical Compatibility
They perform well in chemical processing, water treatment, and industrial fluid handling systems.
Low Maintenance
CPVC backing rings require minimal maintenance due to their non-corrosive and durable material.
Long Service Life
Their resistance to corrosion, scaling, and chemical attack ensures a longer operational life in piping systems.
Cost-Effective Solution
Compared to metal backing rings, CPVC versions offer a more economical option with similar performance in many applications.
Easy Installation
The design allows quick installation with CPVC flanges and pipes, reducing labor time.
Types of CPVC Backing Ring
Solid (Full Face) CPVC Backing Ring
- Manufactured as a single solid ring.
- Provides strong and uniform support to CPVC flanges.
- Commonly used in standard flanged piping systems
Split CPVC Backing Ring
- Designed in two separate halves.
- Easy to install around existing pipes without dismantling the piping system.
- Suitable for maintenance and retrofit applications.
Heavy Duty CPVC Backing Ring
- Thicker and stronger than standard backing rings.
- Used in high-pressure or heavy industrial piping systems.
Light Duty CPVC Backing Ring
- Designed for low-pressure or small-diameter piping systems.
- Lightweight and cost-effective for basic applications.
Standard ANSI/PN Backing Ring
- Manufactured according to standard flange drilling patterns such as ANSI or PN standards.
- Ensures compatibility with standard CPVC flanges used in industrial piping systems.
Applications of CPVC Backing Ring
Process Industry
High Purity Applications
Electronic Industry
Electrical Industry
Semi-conductors Industry
Pharmaceutical Industry
Solar power panels
Sugar Industry
Paper & Pulp Industry
Nuclear Power Industry
Automotive Industry
DI water plants
Why Choose Petron Thermoplast?
At Petron Thermoplast, CPVC Backing Rings are critical components in piping systems, ensuring smooth flow transitions and efficient use of space. Understanding the dimensions and applications of the CPVC Backing Ring is essential for designing reliable and efficient piping systems. By adhering to standards such as ASME B16.9, engineers can ensure compatibility and performance across various industries.
