Fiberglass Reinforced Plastic Pipes & Fittings

Introduction to FRP Pipes

What are FRP pipes? In a nutshell, Fiber Reinforced Plastic (FRP) pipes are strong, lightweight, and highly resistant to corrosion and abrasion. They are made from a composite of resin and reinforcement fibers like glass, ensuring durability and long-lasting performance. Fiberglass equipment has use in variety of industries like chemical, pharmaceuticals, power, water and wherever there is a need to handle aggressive chemicals, fluids and gases. Thanks to the excellent cost-to-performance ratio of fiberglass, FRP pipes are commonly used for transporting corrosive liquids.

Why choose FRP Over Traditional Materials? In many cases, fiberglass reinforced plastic products can be a replacement for traditional steel material, due to FRP cost effectiveness and excellent resistance. FRP pipes are suitable for both above ground and under ground uses, and because of their light weight, these pipes have a huge advantage during transportation and installation of the equipment.

Main Advantages and Properties of FRP Pipes

Corrosion resistance – in FRP is achieved through the polymer matrix (epoxy vinyl ester and polyester), which offers protection against a wide range of corrosive chemicals and acids. Additionally, since Fiber Reinforced Plastic does not contain iron, it is immune to oxidation and rust.

Abrasion Resistance – A blend of polyester or epoxy vinyl ester resin with silicon carbide mash powder is highly effective for handling abrasive slurries. The resin offers corrosion resistance, while the silicon carbide addresses wear concerns. The amount of silicon carbide additive varies based on the service conditions and the substances flowing through the pipe. The percentage content of powder to weight of resin can reach up to 40%, however exceeding this limit may overly thicken and harden the resin, making application difficult. An abrasion-resistant layer can be applied to both newly fabricated equipment and existing systems.

Dimensional stability – in FRP comes from the fact that reinforced glass fibers have a relatively low Coefficient of Thermal Expansion (CTE), meaning they expand and contract very little with temperature fluctuations. This, combined with the resin, creates a rigid structure that maintains its shape, even when subjected to mechanical stress.

Static Charge Buildup Resistance – While FRP is naturally non-conductive, the flow of explosive gases can generate static electricity. To safely dissipate this charge, carbon veil can be incorporated into the resin as a first layer. Combined with conductive connections, this enables grounding between pipe sections, making it particularly valuable in industries like pharmaceuticals, where controlling static electricity is crucial for preventing sparks, explosions, and contamination.

Lightweight – The resins used in FRP fabrication have a much lower density compared to metals like steel. Despite its lightweight nature, FRP boasts high tensile and compressive strength. This makes it an ideal solution in applications where weight reduction is crucial for efficiency and performance.

How to Make Fiberglass Pipe: Manufacturing and Fabrication

At Abtrex, we employ two techniques for production process of FRP pipes: contact molding and spray-up methods. Both are industry-standard processes widely used in the field. Each method involves different approaches to layering and reinforcing composite materials, resulting in variations in production efficiency and structural characteristics.

Contact molding, also known as hand lay-up

Contact molding is a manual fabrication technique that involves placing layers of reinforcing fibers, such as glass or carbon fibers, onto a mold and impregnating them with a liquid resin. This process is carefully controlled to ensure uniform fiber distribution and thorough resin saturation, which enhances the pipe’s mechanical strength and chemical resistance. Multiple layers are built up to achieve the required thickness, with each layer serving a specific function, from providing a smooth, corrosion-resistant inner surface to forming the structural and protective outer layers. Since it is a labor-intensive process, contact molding is most suitable for custom or low-volume production where high strength and precision are required.

Spray-up

Spray-up fabrication technique is a more automated and efficient process than contact molding. It involves simultaneously spraying chopped fiber strands and resin onto a rotating mandrel or mold using a specialized spray ‘chopper’ gun. This technique allows for faster production compared to contact molding, making it more efficient for large-scale manufacturing. The automation of fiber spraying reduces manual labor while still maintaining good structural performance. While spray-up is faster and requires less manual labor compared to contact molding, it generally results in a laminate with randomly oriented fibers, which can slightly reduce the structural strength compared to hand-laid continuous fibers. However, rolling or compaction is often used to enhance fiber bonding and eliminate air pockets.

Both contact molding and spray-up methods offer advantages depending on the specific requirements of the FRP pipe, such as strength, customization, and production volume. While contact molding is preferred for high-strength, custom applications, spray-up provides a faster and more cost-effective approach for large-scale production.

To learn more about the FRP material (resin and glass) we use in the manufacturing process go to FRP overview page.

FRP pipe construction

Inner surface (1) is smooth, non-porous, and highly resistant to corrosion. It is a first layer that comes into contact with the solution, so the chemical and corrosion resistance is crucial. It consists of 90% of resin and 10% of veil, with each layer being 10 mils thick and up to two layers possible

Interior layer (2) is key for increase chemical resistance and initial mechanical strength. This layer consists of chopped strand mat impregnated with resin and properly rolled to form a reinforced composite structure. It consists of approximately 60% resin and 40% chopped strand mat, with 2-5 layers, each layer measuring .043 mils of mat saturated in resin.

Structural layer (3) is the primary load-bearing component of the FRP pipe. It provides strength, stiffness, and pressure resistance, allowing the pipe to endure external loads, internal pressure, and mechanical stress. This layer is built up using multiple layers of woven roving alternate with chopped strand mat to ensure optimal reinforcement. The resin fully saturates the fibers, bonding them together and preventing delamination. This layer determines the pipe’s overall mechanical performance and longevity. It consists of 50% resin and 50% glass, with each layer measuring 0.33 mils.

Exterior layer (4) protects the pipe from environmental factors such as UV radiation, moisture, and external abrasion. This layer consists of “C” glass reinforcing fibers and a thin finish coat of exterior gel, providing an additional shield against mechanical wear and environmental degradation. In some cases, additional coatings or UV stabilizers may be applied to enhance durability, particularly for outdoor applications.

The Mechanical Properties of FRP Pipe (73 Degrees F)

Thickness Pressure Rate – Standard Corrosion Barrier

The corrosion barrier is essential for safeguarding pipes from chemical damage. Its thickness directly influences the overall pipe thickness and pressure rating. Some customers require the barrier to be a separate thickness entity from the structural layers, as extra protection.

At Abtrex, for pipe strength, we apply a safety factor of 10:1 for internal pressure and 5:1 for external pressure.

• Modulus of elasticity: 1,000,000 PSIG
• Ultimate Tensile Strength: 15,000 PSIG
• Safety Factor for Internal Pressure: 10
• Safety Factor for External Pressure: 5

Pipe Hanger Spacing at Pressure Rating

Duct Piping Specification

Fiberglass duct piping is designed for handling and evacuating gases and fumes in various industrial applications. Its lightweight yet durable construction allows it to withstand harsh conditions while being easy to install. This makes it a reliable alternative to traditional metal ducting.

Duct Hanger Spacing

The table below displays the recommended distances between support hangers for the duct. Proper hanger spacing is essential to prevent sagging, preserve structural integrity, and allow for thermal expansion.

Fiberglass Reinforced Plastic Fittings

FRP Flanges

At Abtrex, we offer high-quality FRP flanges ranging from 1” to 36” in diameter. Engineered for durability and precision, our flanges are designed to meet the highest industrial standards and ensure reliable connections across various applications.

Types of FRP Flanges We Offer:

• Full-Face Flanges: Provide a secure and comprehensive seal, ideal for high-pressure systems requiring maximum strength and stability.
• Lap Joint Flanges: Designed for easy assembly and alignment, these flanges are perfect for systems where frequent disassembly is necessary.
• Flanges on Pipe: Integrated directly onto pipes, these flanges offer seamless connections that enhance the efficiency and reliability of your piping system

Reducers

At Abtrex, we specialize in fabricating high-quality FRP (Fiberglass Reinforced Plastic) reducers designed to meet the diverse needs of industrial applications. Our range includes concentric, eccentric, and custom reducers available in diameters from 1” to 30”, ensuring the perfect fit for your specific system requirements.

Types of FRP Reducers We Offer:

• Concentric Reducers: Ideal for maintaining an even flow by symmetrically reducing the pipe size. Perfect for vertical pipelines where flow alignment is crucial.
• Eccentric Reducers: Designed to keep the pipeline flow level on one side, making them the ideal choice for horizontal pipelines, preventing air pockets and maintaining smooth flow.
• Flange Reducers: Featuring flanges on both ends, these are commonly used on pumps and tanks to ensure a secure and leak-free connection.
• Reducing Spools: A flange-free option on one end or FRP blind end with a smaller nozzle installed, these reducers help manage and reduce flow within the piping system efficiently.
• Plain Reducers: Designed with plain ends, these reducers offer a straightforward connection solution for various piping systems.

Custom FRP Reducers for Unique Needs

For projects that demand non-standard solutions, we offer fully customized reducers. Whether you need concentric or eccentric reducers with unique dimensions, we can manufacture according to your specific requirements, including calculations beyond standard formulas like 2.5*(D1-D2)** to ensure a precise fit.

FRP Elbows, Tees, Crosses, and Laterals: Versatile Piping Solutions

We offer expertly crafted FRP elbows, tees, crosses, and laterals designed to meet the diverse needs of industrial piping systems.

FRP Elbows

Our long-radius elbows are available in sizes from 1” to 36” in diameter. Each elbow is molded as a one-piece component, ensuring seamless construction and enhanced durability. All our standard molds feature a radius of 1.5 times the diameter for optimal flow efficiency.

• Standard available angles: 90°, 45°, and 60° + custom-build angles
• Options include smooth short and long-radius elbows
• One-piece elbows with the option of integrated flanges for added convenience

FRP Tees, Crosses, and Laterals

Our tees, crosses, and laterals are meticulously hand-manufactured and built directly onto the pipe for enhanced structural integrity. These fittings are crafted from high-quality FRP pipe and are available in the same size range as our piping systems, ensuring seamless compatibility.