Corrosion-resistant FRP stub flanges designed for industrial piping systems, offering lightweight performance, long service life, and reliable connections in harsh environments.
Description
FRP Stub Flanges are corrosion-resistant piping components designed for industrial systems operating in harsh and chemically aggressive environments. Manufactured using high-quality resin systems and fiberglass reinforcement, these flanges provide reliable mechanical performance and long service life compared to traditional metal alternatives.

FRP stub flanges are commonly used in conjunction with backing rings to form strong and secure pipe connections while allowing flexibility in installation and maintenance. They are suitable for a wide range of applications including water treatment, chemical processing, marine environments, and industrial infrastructure.
These flanges offer excellent resistanc
FRP Stub Flange vs Metal Flange
FRP (fiber-reinforced plastic) stub flanges are engineered for aggressive, chemically corrosive service where metal flanges may require coatings, heavy alloys, or frequent replacement. They also reduce weight and ease handling during installation.
| Feature | FRP Stub Flange | Metal Flange |
|---|---|---|
| Corrosion resistance | Excellent in acids/chemicals | Depends on alloy/coating |
| Weight | Lightweight | Heavy |
| Maintenance | Low | May require coatings & inspections |
| Lifecycle cost | Often lower in harsh environments | May be higher over time |
Explore related products in our FRP piping systems.
FRP Stub Flange FAQ
What is an FRP stub flange?
An FRP stub flange is a corrosion-resistant flange used with fiberglass piping systems to provide strong, reliable connections in industrial service.
Where are FRP stub flanges used?
Typical applications include water & wastewater treatment, chemical processing, marine environments, and other industrial infrastructure.
How is it different from a metal flange?
FRP flanges are lighter and corrosion-resistant, while metal flanges may provide higher mechanical strength in certain applications but typically require protective coatings or specialized alloys to withstand aggressive chemical environments.
These flanges offer excellent corrosion resistance, lightweight handling, and reduced installation costs. Compared to traditional metal flanges, they eliminate the need for protective coatings in harsh environments, resulting in lower long-term maintenance requirements.
Available in various sizes and configurations, FRP stub flanges can be customized to meet specific project requirements, including different resin systems, pressure ratings, and drilling standards.
Key Features:
- Excellent corrosion resistance in aggressive environments
- Lightweight and easy to install
- Compatible with standard piping systems
- Long service life with minimal maintenance
- Customizable sizes, drilling patterns, and resin systems
Applications:
- Water and wastewater treatment
- Chemical processing plants
- Marine and coastal environments
- Industrial piping systems
- Infrastructure projects
FRP Stub Flange Dimensions (ANSI ID)
| Nominal Diameter (d) | Pressure Rating | Flange Diameter (D) | Flange Thickness (T) | Stub Length (L) | Stub Thickness (t) | Hub Length (HL) | Hub Thickness (HT) | No. of Holes (n) | Bolt Hole Diameter (h) | Washer Diameter (S) | Bolt Circle Diameter (C) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| inch | psi | inch | inch | inch | inch | inch | inch | pcs | inch | inch | inch |
| 1/2 | 150 | 3-3/4 | 5/8 | 12 | 3/16 | 2-1/2 | 5/16 | 4 | 5/8 | 1-1/4 | 2-3/8 |
| 3/4 | 150 | 4-1/8 | 5/8 | 12 | 3/16 | 2-1/2 | 5/16 | 4 | 5/8 | 1-1/4 | 2-3/4 |
| 1 | 150 | 4-1/2 | 5/8 | 12 | 3/16 | 2-1/2 | 5/16 | 4 | 5/8 | 1-1/4 | 3-1/8 |
| 1-1/2 | 150 | 5-1/2 | 11/16 | 12 | 3/16 | 2-3/4 | 11/32 | 4 | 5/8 | 1-1/4 | 3-7/8 |
| 2 | 150 | 6-1/2 | 11/16 | 12 | 1/4 | 2-3/4 | 11/32 | 4 | 3/4 | 1-1/2 | 4-3/4 |
| 2-1/2 | 150 | 7-1/2 | 3/4 | 12 | 1/4 | 3 | 3/8 | 4 | 3/4 | 1-1/2 | 5-1/2 |
| 3 | 150 | 8 | 13/16 | 12 | 1/4 | 3-1/4 | 13/32 | 4 | 3/4 | 1-1/2 | 6 |
| 4 | 150 | 9-1/2 | 15/16 | 12 | 1/4 | 3-3/4 | 15/32 | 8 | 3/4 | 1-1/2 | 7-1/2 |
| 5 | 150 | 10-1/2 | 1 | 12 | 3/8 | 4 | 1/2 | 8 | 7/8 | 1-3/4 | 8-1/2 |
| 6 | 50 | 11-1/2 | 5/8 | 12 | 3/16 | 2-1/2 | 5/16 | 8 | 7/8 | 1-3/4 | 9-1/2 |
| 6 | 150 | 11-1/2 | 1-1/16 | 12 | 3/8 | 4-1/4 | 17/32 | 8 | 7/8 | 1-3/4 | 9-1/2 |
| 8 | 50 | 14 | 3/4 | 12 | 1/4 | 3 | 3/8 | 8 | 7/8 | 1-3/4 | 11-3/4 |
| 8 | 150 | 14 | 1-1/4 | 12 | 7/16 | 5 | 5/8 | 8 | 7/8 | 1-3/4 | 11-3/4 |
| 10 | 50 | 16-1/2 | 7/8 | 12 | 1/4 | 3-1/2 | 7/16 | 12 | 1 | 2 | 14-1/4 |
| 10 | 150 | 16-1/2 | 1-7/16 | 12 | 1/2 | 5-3/4 | 23/32 | 12 | 1 | 2 | 14-1/4 |
| 12 | 50 | 19-1/2 | 1 | 12 | 1/4 | 4 | 1/2 | 12 | 1 | 2 | 17 |
| 12 | 150 | 19-1/2 | 1-3/4 | 12 | 5/8 | 7 | 7/8 | 12 | 1 | 2 | 17 |
| 14 | 50 | 21-1/2 | 1-1/16 | 12 | 5/16 | 4-1/4 | 17/32 | 12 | 1-1/8 | 2-1/4 | 18-3/4 |
| 14 | 150 | 21-1/2 | 1-7/8 | 12 | 3/4 | 7-1/2 | 15/16 | 12 | 1-1/8 | 2-1/4 | 18-3/4 |
| 16 | 50 | 24 | 1-3/16 | 12 | 5/16 | 4-3/4 | 19/32 | 16 | 1-1/8 | 2-1/4 | 21-1/4 |
| 16 | 150 | 24 | 2 | 12 | 13/16 | 7 | 1 | 16 | 1-1/8 | 2-1/4 | 21-1/4 |
| 18 | 50 | 25-1/2 | 1-1/4 | 12 | 3/8 | 5 | 5/8 | 16 | 1-1/4 | 2-1/2 | 22-3/4 |
| 18 | 150 | 25-1/2 | 2-1/4 | 12 | 7/8 | 7-7/8 | 1-1/8 | 16 | 1-1/4 | 2-1/2 | 22-3/4 |
| 20 | 50 | 28 | 1-5/16 | 12 | 3/8 | 5-1/4 | 21/32 | 20 | 1-1/4 | 2-1/2 | 25 |
| 20 | 150 | 28 | 2-7/16 | 12 | 15/16 | 7-5/16 | 1-7/32 | 20 | 1-1/4 | 2-1/2 | 25 |
| 24 | 50 | 32-1/2 | 1-1/2 | 12 | 7/16 | 6 | 3/4 | 20 | 1-3/8 | 2-3/4 | 29-1/2 |
| 24 | 150 | 32-1/2 | 2-13/16 | 12 | 1-1/8 | 8-7/16 | 1-13/32 | 20 | 1-3/8 | 2-3/4 | 29-1/2 |
| 30 | 50 | 39-1/4 | 1-7/8 | 12 | 1/2 | 7-1/2 | 15/16 | 28 | 1-3/8 | 2-3/4 | 36 |
| 30 | 150 | 39-1/4 | 3 | 12 | 1-3/8 | 7-1/2 | 1-1/2 | 28 | 1-3/8 | 2-3/4 | 36 |
| 36 | 50 | 46 | 2 | 12 | 5/8 | 8 | 1 | 32 | 1-5/8 | 3-1/4 | 42-3/4 |
| 36 | 150 | 46 | 3-1/2 | 12 | 1-5/8 | 8-3/4 | 1-3/4 | 32 | 1-5/8 | 3-1/4 | 42-3/4 |







