FAQs: Fibreglass Reinforced Plastic (FRP)

What is FRP? 

Fibre Reinforced Plastic (FRP) – also called Fibre Reinforced Polymer – is a composite material manufactured by combining a matrix of polymer resins reinforced with specific fibres. FRP is stronger by weight than most of its traditional alternatives including steel and aluminium. 

What exactly is FRP made from?  

FRP is a matrix of fibres and resins. There are several fibres commonly used in manufacturing FRP and these are generally responsible for giving FRP its strength. Common fibres include carbon, basalt and Kevlar, however, the most commonly used is glass fibre.    

The polymer resins used in FRP help determine its ultimate physical performance including its flexibility, chemical resistance, electrical conductivity and thermal properties. Most resins used in FRP manufacture are of the thermosetting type. The resin is ‘cured’ under low heat or pressure and once formed it can’t be reformed or melted. Thermosetting resins typically include Orthopthalic, Isopthalic, Vinyl Ester and Phenolic resins but are not limited to these.   

What’s the difference between FRP and GRP?  

Reinforced polymer also called reinforced plastic (RP) can incorporate fibres beyond just glass. When glass fibres are used, it’s referred to as Glass Reinforced Plastic / Polymer (GRP) or Glass Fibre Reinforced Plastic / Polymer (GFRP). On the other hand, if carbon fibres are used, it’s commonly known as Carbon Fibre Reinforced Plastic / Polymer (CFRP). 

Is glass reinforced FRP the same as Fibreglass?   

The answer is ‘not exactly’. Fibreglass is created when glass is spun into a fibre form. This glass fibre can be used without any additional resins in items such as ‘glass wool’ insulation. Although the addition of resin to glass fibres can be called FRP, the glass in most fibreglass is laid in mats with multidirectional or random fibre distribution.  The glass fibres in FRP are generally laid in uni-directional or bi-directional patterns and evenly distributed throughout the resin matrix (all neatly lined up in one or two directions) to meet specific strength and deflection requirements. 

How Green is FRP? 

Let’s compare the Sustainability of Fibreglass Reinforced Plastic (FRP) with old-fashioned materials like concrete and iron, for use in public spaces. That’s looking at things like trench covers, manhole covers, bridges, walkways and safety structures. 

Sustainability is often measured across three main aspects, these are: 

• Social – this includes items like safety, security and convenience, 
• Environmental – things like energy consumption, emissions, waste, and virgin material use. This is what we call the ‘green footprint’. 
• Economic – includes purchase price, transport, life cycle, repair and maintenance costs and return on investment. 

Some things can cross over more than one category. For example, when we measure how sustainable FRP is in relation to transport, it can fall under all three categories: 

• Economic (lighter weight = lower transport costs per unit) 
• Environmental (lighter weight = more efficient transportation, less equipment needed at installation, reduced traffic congestion due to quicker installation) 
• Social (lighter weight = easier to handle during transport = safety) 

Several good studies have already shown how well FRP performs against aluminium, concrete, iron, and steel in terms of strength. 

There hasn’t been much work done on how they compare for sustainability. A good study that looks at all three aspects of sustainability is ‘Bridge decks of fibre reinforced polymer (FRP): A sustainable solution.’* 

We’ve also put together some information in a graphic you can access here FRP Green Footprint.pdf. We’re thrilled to report that FRP is more sustainable than concrete, iron, and steel. Composites get the tick of approval across all three categories including for their ‘green footprint’. 

What is the design life of FRP? 

FRP is known for its durability and resistance to corrosion, but the design life of Fiber-Reinforced Polymer (FRP) materials can vary depending on several factors, including the type of resin and fibres used, environmental conditions, loading conditions, and the specific application.  

In general, FRP materials are designed to have a long service life, often exceeding 50 years or more in certain applications. However, it’s important to note that the actual performance of FRP structures in real-world conditions may depend on how well they are manufactured, installed, and maintained. 

When considering the design life of FRP, engineers typically take into account factors such as: 

• Material Properties: The type of resin (e.g., polyester, vinyl ester, epoxy) and the type of fibres (e.g., glass, carbon, aramid) used in the FRP composite can significantly affect its durability. 
• Exposure Conditions: Environmental conditions, such as temperature, humidity, and exposure to chemicals, can impact the long-term performance of FRP materials. Exposure to harsh chemicals or extreme temperatures may affect the material over time. 
• Loading Conditions: The type and magnitude of loads that the FRP structure will experience are important considerations. Structures subjected to heavy loads or cyclic loading may have different design life expectations. 
• Installation and Maintenance: Proper installation and regular maintenance are crucial for maximising the design life of FRP structures. Improper installation or lack of maintenance can lead to premature degradation. 
• Industry Standards: Adherence to industry standards and guidelines for FRP design, fabrication, and installation can contribute to achieving the intended design life. 

It’s important for engineers to consider these factors and follow best practices to ensure the longevity of FRP structures in specific applications. Additionally, ongoing research and advancements in materials and manufacturing techniques may continue to improve the durability and design life of FRP materials. 

Is FRP recyclable?

In theory, FRP can be recycled, and there is huge potential for new products to be developed from recycled FRP materials. However, it is not currently economically viable to recycle FRP on a large scale.