FRP Pipe Supports: Design Considerations for Fiberglass Reinforced Plastic Piping Systems

Fiberglass Reinforced Plastic (FRP) piping systems require specialized pipe support design to ensure long-term performance, safety, and compliance with engineering standards. At JSC Engineers, we deliver FRP pipe support solutions that prevent damage, maintain proper alignment, and extend the service life of fiberglass pipelines.

Why FRP Pipe Supports Are Different

While the basic principles of pipe support design apply to both FRP and metallic piping, fiberglass systems introduce unique challenges due to their material properties. FRP is an anisotropic composite, meaning it exhibits different strength and stiffness depending on the direction of the reinforcement and the type of resin used. As a result, the modulus of elasticity, thermal expansion rate, and allowable stresses differ significantly from steel or thermoplastics.

• FRP thermal expansion is 2–5 times greater than steel.
• Outside diameters do not match steel pipe standards — supports must be custom-sized.
• FRP is non-ductile, making it more sensitive to point loads and stress concentrations.
• Surface irregularities can cause chafing if supports are not properly lined.

Key Design Principles for FRP Pipe Supports

FRP pipe supports must be engineered to avoid localized stress, control deflection, and maintain the pipe’s round shape. Based on manufacturer guidelines and field experience, JSC Engineers recommends the following design considerations:

• Use elastomeric liners (rubber or cork) in all supports to prevent wear and chafing.
• Wider, more robust saddles to spread loads and maintain roundness.
• Custom clamp sizing to match FRP outside diameters.
• Support spacing closer than steel but greater than thermoplastic piping — always follow manufacturer’s technical bulletins.
• Avoid direct steel contact to prevent abrasion and localized failure.
• Place supports near heavy in-line equipment such as valves and flanges.
• Anchor directional changes in non-tensioned systems to prevent joint separation.

Types of FRP Pipe Supports

Depending on system requirements, supports are typically classified into:

• Weight Supports – Carry the dead load of the pipe and its contents.
• Guides – Provide lateral restraint while allowing axial movement.
• Anchors – Restrict all movement to control thermal expansion or system forces.

Each support must be designed to function exactly as modeled in the FRP pipe stress analysis. For example, if a guide was intended to control lateral loads, it must be stiff enough in that direction to perform its role effectively.

Support Placement and Joint Considerations

FRP joint locations must be considered in the support layout. Typical adhesive or O-ring joints are approximately one pipe diameter in width, so supports should not be placed directly on joints. If unavoidable, reinforced saddles and modified designs are required.

For vertical runs, O-ring connection sockets should face downward to avoid water accumulation, which can cause freeze damage in cold climates.

Common FRP Support Issues and How to Avoid Them

• Using steel pipe supports without modification — leads to poor fit and uneven load distribution.
• Improper clamp torque — can crush or deform the pipe wall.
• Insufficient saddle length — increases localized bearing stress and ovalization risk.
• Supports lacking stiffness — allows ovalization and stress concentrations.

Integrating FRP Support Design with Pipe Stress Analysis

One of the most critical inputs to FRP pipe support design comes from pipe stress analysis. The calculated loads, thermal movements, and displacement profiles inform the selection, sizing, and placement of supports. At JSC Engineers, our FRP pipe support design process includes:

• Evaluating axial, lateral, and vertical loads from stress analysis results.
• Designing supports that match the stiffness and restraint requirements of the model.
• Custom-fabricating supports to match FRP dimensions and environmental conditions.

Applications of FRP Pipe Supports

FRP piping is common in industries where corrosion resistance and chemical compatibility are critical, including:

• Chlor-alkali production
• Water and wastewater treatment
• Chemical processing plants
• Seawater cooling systems
• Desalination facilities

Partner with JSC Engineers for FRP Pipe Support Solutions

Proper FRP pipe support design is essential for long-term system reliability. At JSC Engineers, we combine delegated piping design expertise with FRP material knowledge to deliver solutions that minimize maintenance, extend service life, and ensure code compliance. Contact our team to discuss your FRP support requirements.

Contact JSC Engineers today to schedule a consultation on your FRP pipe support project.