We are often asked “What is a composite and what is the difference between FRP and GRP?”


We agree that a lot of terms used in the composites industry are confusing. Let’s try to clarify the terminology.

By definition, a “composite” is an engineering material consisting of 2 or more dissimilar materials. These dissimilar materials are usually classed as the matrix and the reinforcement. The matrix can be plastic (or “polymer”), metal or ceramic and the reinforcement is either particulate or fibre based.

In practice, the vast majority of “composites” are fibre reinforced plastics, hence the term FRP. The type of fibre could be glass, carbon, aramid etc. and the type of matrix would be resins such as polyester, vinyl ester, epoxy.  If the reinforcing fibre is glass, the composite can also be referred to as glass reinforced plastic or “GRP”.

Although the terms ‘Composite’ and ‘FRP’ are generally synonymous, i.e. they are both taken to mean fibre reinforced plastic or polymer, the term “composite” tends to imply the use of carbon fibre reinforcing fibres and to be associated more with the high performance end of the market, e.g. aerospace. “FRP” is a term more likely to be used when referring to engineering materials used in industrial applications.

“GRP”, glass reinforced plastic, on the other hand is rarely used for high performance applications and although can refer to true engineering composites, “GRP” is a term usually reserved for low performance applications such as swimming pools, shower cubicles, etc.

P1000877 resized 1

In the FRP Asset Manual, the term FRP is generally used and whereas the majority of composites referred to are glass reinforced plastics, as the applications require a true engineering class of materials “FRP” is the correct terminology to use.

Comments are closed.