When designing piping systems for corrosive or demanding environments, material selection is critical. Two common solutions used in chemical processing and industrial applications are dual laminate pipes and lined pipes. While these systems may appear similar at first glance, they differ significantly in construction, performance, and long-term reliability.
At Custom Fiberglass Products Inc., we work with both systems and help customers choose the best option based on real-world operating conditions. Here’s a breakdown of how dual laminate and lined pipes compare — and when each makes sense.
What Are Dual Laminate Pipes?
Dual laminate pipe systems combine two materials into a single, integrated structure:
- An inner corrosion-resistant liner (such as PVDF, PP, PVC, CPVC, or ECTFE/Halar)
- An outer structural layer, typically fiberglass-reinforced plastic (FRP)
Unlike simple liners, the thermoplastic liner in a dual laminate system is chemically bonded and mechanically integrated with the fiberglass structure during fabrication. This creates a unified pipe system where each material performs a specific role.
Key Characteristics of Dual Laminate Pipes
- Excellent chemical resistance from the thermoplastic liner
- High structural strength from the FRP exterior
- Strong bond between liner and structure
- Designed as a single engineered system
What Are Lined Pipes?
Lined pipes typically consist of:
- A structural pipe (often steel or FRP)
- A loose or bonded liner made from a corrosion-resistant material such as PTFE, rubber, or thermoplastic
In many lined systems, the liner is inserted, mechanically held in place, or bonded after the structural pipe is manufactured. The liner and pipe are often treated as separate components rather than a single integrated system.
Key Characteristics of Lined Pipes
- Structural support provided by the outer pipe
- Corrosion protection provided by the liner
- Liner may not be fully bonded or load-sharing
- Often used for retrofits or standardized piping
Key Differences Between Dual Laminate and Lined Pipes
1. Structural Integration
- Dual laminate pipes are engineered as a single unit, with the liner and fiberglass structure working together.
- Lined pipes typically rely on the outer pipe for strength, while the liner serves only as a corrosion barrier.
This integration gives dual laminate systems a major advantage in demanding environments.
2. Liner Attachment & Reliability
- In dual laminate systems, the liner is fused and mechanically locked into the fiberglass, reducing the risk of separation.
- In lined pipes, liners can blister, wrinkle, or detach over time due to thermal cycling or pressure changes.
For long-term reliability, liner bonding is a critical factor.
3. Pressure & Vacuum Performance
- Dual laminate pipes perform well under both pressure and vacuum conditions because the liner is supported by the FRP.
- Lined pipes may struggle under vacuum or rapid pressure changes if the liner is not fully supported.
This makes dual laminate systems well-suited for scrubbers, exhaust systems, and chemical transfer lines.
4. Fabrication & Customization
- Dual laminate pipes allow for highly customizable designs, including complex fittings, elbows, reducers, and flanges.
- Lined pipes are often limited to standard sizes and configurations.
For custom or non-standard applications, dual laminate is typically the preferred option.
5. Maintenance & Lifecycle Cost
- Dual laminate systems generally offer longer service life with less maintenance.
- Lined pipes may require periodic liner inspections, repairs, or replacements.
While lined pipes may have a lower upfront cost, dual laminate systems often provide lower total lifecycle cost.
When to Choose Dual Laminate Pipes
Dual laminate pipes are often the best choice when:
- Handling highly corrosive chemicals
- Operating under pressure or vacuum
- Long service life is critical
- Custom fabrication is required
- Downtime or failure carries high risk
When Lined Pipes May Be Appropriate
Lined pipes can be a good option when:
- The application is relatively standardized
- Operating conditions are less severe
- Cost constraints are a primary concern
- Retrofitting an existing system
Choosing the Right System for Your Application
There is no one-size-fits-all answer. The right choice depends on:
- Chemical exposure
- Temperature and pressure
- Mechanical stresses
- Installation environment
- Long-term maintenance expectations
At Custom Fiberglass Products Inc., we evaluate these factors to help customers select a piping system that performs reliably — not just on day one, but for years to come.
Trusted Dual Laminate & Lined Pipe Solutions
With experience in fiberglass fabrication, thermoplastics, and dual laminate systems, Custom Fiberglass Products Inc. provides custom-built solutions for demanding industrial environments.
If you’re comparing dual laminate pipes and lined pipes — or need help evaluating your existing system — contact our team. We’re here to help you make the right material choice.