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Plastic Flanges

If metal flanges risk corrosion or stress cracking in your process line, plastic flanges offer a longer service life. Our UPVC, CPVC, and HDPE flange systems reduce bolt load and resist chemicals across full pH range. 

Standard Specification

ASTM D1785 (UPVC), ASTM F441 (CPVC), ISO 4427 (HDPE)

Pressure Rating

PN6 to PN16 (UPVC), PN10 to PN20 (CPVC), PN6 to PN25 (HDPE)

Material

UPVC (Type I/II), CPVC (4120), HDPE (PE100), PVDF (for chemicals)

Nominal Size

½” to 24″ (DN15 to DN600)

Flange Type

Loose flange + stub end
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Product Description

Incorrect flange matching leads to leaks or warping during thermal expansion. We solve this using loose flanges with matched stub ends that accommodate movement without damage.

Facing Type

Flat Face (FF) [With elastomeric gasket]

Dimensions

ASME B16.47 Series B (modified) [Reduced bolt load]

Bolt Circle Diameter

Matches metal flange [±2mm tolerance]

Number & Size of Bolt Holes

Larger holes for plastic expansion

Surface Finish

Molded (as-is) or machined (63-125 μin Ra)

Corrosion Resistance

Excellent (pH 0-14 for PVDF) [Stress-crack tested per ASTM D1693]

Temperature Rating

Up to 93°C depends upon material

Material Certification

NSF/ANSI 61 (potable water), FDA 21 CFR (food grade)

Gasket Compatibility

EPDM, Nitrile, FPM [Full-face, non-metallic]

Coating/Plating

None [UV-stabilized compounds for outdoor use]

Manufacturing Method

Injection-molded (≤12″), Fabricated (≥14″) [Butt-welded/electrofused for HDPE]

Technical Advantages

Plastic backing rings prevent cracking under cyclic loads using large bolt holes that allow expansion movement. Stub ends avoid over-compression during tightening, improving long-term sealing. 
Our molded or machined faces accept full-face elastomeric gaskets for broad compatibility with common media. All sizes up to 24 inches support either PN6 or PN25 ratings depending on material. 

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Industry Applications

Water Treatment Plants

Works with dosing lines and filter housings, resisting chlorine and acidic cleaning agents. 

Chemical Transfer Systems

CPVC and PVDF models hold up under caustics and solvents at up to 93°C. 

Food and Beverage Plants

HDPE and UPVC units meet NSF and FDA specs for CIP lines and ingredient transport. 

Underground Irrigation Networks

UV-stabilized HDPE withstands soil chemicals and buried stress over long cycles. 

Pharmaceutical Units

Smooth-face flanges allow sterile, gasketed joints in pressure-tested cleanroom pipelines.

Desalination Facilities

Corrosion-proof flanges withstand high salinity and pressure cycling in brine reject loops. 

Long-Term Sealing in Harsh Chemical Lines

Systems handling acids, brine, or chlorinated water need flange setups that won’t pit or split. Our plastic flanges avoid these failures using resin blends tested for long-term crack resistance. 
 Metal flanges add weight and corrode under UV or aggressive pH ranges, raising replacement cost. We use UV-stabilized and food-grade materials to keep performance intact under changing flow conditions. 

Related products

Having Doubts? Our FAQ

Check all our Frequently Asked Question

Can these plastic flanges match with existing metal pipeline interfaces?

Yes, the bolt circle and diameter follow metal flange patterns with a ±2 mm tolerance. This helps avoid mismatch issues during metal-to-plastic transitions. Buyers can standardize flange connections across both material types.

Will the flange hold shape under long-term line pressure or chemical stress?

The material passes ASTM stress-crack tests, ensuring no creep or deformation under rated loads. For high-chemical exposure, PVDF options offer full pH resistance. That allows dependable use in both acidic and alkaline systems.

Is there a flange option for quick field replacement or line retrofitting?

Yes, the loose flange plus stub-end setup simplifies alignment without needing flange rotation. It suits fast changes in maintenance-heavy layouts. Fabricated HDPE models are also available for larger pipe upgrades.

Can I use the same gasket for different plastic flange types?

Yes, full-face rubber or fiber gaskets work across UPVC, CPVC, and HDPE variants. All flange facings follow flat-face configurations to prevent over-compression. This reduces inventory needs for buyers managing mixed-line plants. 

How do you handle large-diameter flange strength above 12 inches?

We fabricate larger sizes using butt-welding or electrofusion, depending on the plastic type. This ensures proper ring support without cracking during bolt tightening. It also keeps internal bore alignment intact during installation.

Do Frigate supply plastic flanges as part of complete piping assemblies or only as standalone components?
  • Frigate manufactures both standalone flange sets and integrated piping assemblies. 
  • We supply pre-matched flange + stub-end combinations ready for installation. 
  • Assemblies can be delivered pre-tested and tagged for direct plant integration. 
  • Custom kits reduce on-site alignment errors and installation time. 
Can Frigate customize flange dimensions or drilling to match non-standard systems?
  • Yes, we support custom drilling patterns and modified bolt circles. 
  • Our engineering team aligns designs with existing plant specifications or legacy systems. 
  • We maintain tight tolerances (±2 mm or better) for accurate fit-up. 
  • Reverse engineering is available for retrofit or upgrade projects. 
What quality checks does Frigate perform before dispatch?
  • Every batch undergoes dimensional inspection and face flatness checks. 
  • Materials are validated against ASTM/ISO standards and traceable certifications. 
  • We conduct pressure and fitment validation (where applicable). 
  • Final products are shipped with inspection reports and compliance documents. 
How does Frigate ensure long-term reliability in aggressive chemical environments?
  • We use application-specific resin grades (UPVC, CPVC, HDPE, PVDF). 
  • Materials are selected based on media compatibility and temperature exposure. 
  • All products are designed to minimize stress concentration and creep. 
  • Proven performance in high pH, chlorinated, and saline conditions. 
What is the typical lead time for bulk or project-based orders?
  • Standard sizes are available with short lead times from stocked molds. 
  • Custom or large-diameter (>12”) orders are fabricated with defined project timelines. 
  • Frigate supports scheduled deliveries aligned with project milestones. 
  • Dedicated production planning ensures consistent supply for EPC and OEM clients. 
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LOCATIONS

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Operations Office

9/1, Poonthottam Nagar, Ramanandha Nagar, Saravanampatti, Coimbatore-641035, Tamil Nadu, India. ㅤ

Other Locations

  • Bhilai
  • Chennai
  • India
  • Germany
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LOCATIONS

Registered Office

10-A, First Floor, V.V Complex, Prakash Nagar, Thiruverumbur, Trichy-620013, Tamil Nadu, India.

Other Locations

  • Bangalore
  • Chennai
  • India
  • Germany
Become a Frigatian
Become a Supplier

GENERAL ENQUIRIES

  • +91 96778 64606
  • manufacture@frigate.ai
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plastic flanges

Plastic Flanges

Need reliable wires and cables for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

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plastic flanges

Plastic Flanges

Need reliable Machining for your next project? Get in touch with us today, and we’ll help you find exactly what you need!

Get Latest Price

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