Five Things People Get Wrong About GRP
GRP has been used in UK infrastructure for over fifty years. It is on railway lines, in water treatment plants, at nuclear facilities, and on offshore platforms. And yet the same misunderstandings come up in conversations with engineers, contractors, and procurement teams year after year. Here are five of the most common ones, and why they are wrong.
Myth 1: GRP is too expensive
GRP costs more to buy than steel. That part is true. On a like-for-like purchase price comparison, steel almost always wins.
The problem is that purchase price is the wrong comparison. A steel walkway in a water treatment plant needs inspection, repainting, and often partial replacement within 10 to 15 years. A GRP walkway installed in the same environment requires nothing beyond a routine visual check for the life of the asset. Over a 25-year design life, the maintenance saving consistently outweighs the higher initial cost. The HM Treasury Green Book methodology, which applies a 3.5% discount rate over a 30-year asset life, confirms GRP’s whole-life cost advantage in corrosive environments. The engineers and procurement teams who have run the numbers tend not to raise the price objection a second time.
Myth 2: GRP is not strong enough for structural applications
GRP pultruded profiles are manufactured to BS EN 13706 E23 grade, the highest performance classification in the standard. The E23 designation means a minimum tensile modulus of 23 GPa and a minimum flexural modulus of 23 GPa. ENGRail, Engineered Composites’ own GRP handrail system, achieved an ultimate load capacity of 7.159 kN/m in independent testing, a safety factor of 4.77 times the public assembly loading requirement.
GRP is not as stiff as steel in direct comparison, and a competent structural engineer accounts for that in the design. But for walkways, access platforms, handrails, fencing, cable management, and grating, GRP is structurally fit for purpose. It has been proven in service across rail, water, defence, and marine environments for decades.
Myth 3: GRP is only suitable for industrial environments
GRP appears in MRI suites in NHS hospitals, on pedestrian footbridges, in commercial building access platforms, at airports, in research facilities, and on residential balconies. The properties that make it useful in industrial environments, non-conductivity, corrosion resistance, low weight, and long design life, are equally relevant in a wide range of non-industrial applications.
The perception that GRP is an industrial-only material tends to come from where it was most visibly adopted first. That picture is now outdated. Specifiers working in healthcare, education, commercial construction, and aviation specify GRP for the same reasons that water utilities and rail contractors do.
Myth 4: GRP is difficult to work with on site
GRP profiles are cut with standard woodworking tools. A circular saw, a jigsaw, or a hand saw with a fine-toothed blade will cut GRP cleanly. No welding is required. No hot works permit is needed. No specialist installation equipment is necessary. GRP scaffold tubes connect directly to standard Kwikstage and cuplock fittings without modification.
The modular GRP handrail systems ECL supplies use a tube-and-fitting assembly method that any competent maintenance team can install from a drawing. Cut-to-length is available as a free service, meaning components arrive on site ready to assemble. For a contractor managing a tight programme with a restricted site, that matters considerably.
Myth 5: GRP is a newer, less proven material than steel
Pultruded GRP profiles have been in continuous use in UK industrial and infrastructure applications since the 1970s. Engineered Composites has supplied GRP products since 1986. The material is not new, it is not experimental, and it is not unproven. It is simply underspecified in sectors where the default material choice has not been questioned for a long time.
The question is not whether GRP works. It is whether the people writing the next specification know it is a credible option.
If any of these objections have come up in your own projects, the Engineered Composites team is happy to work through the numbers with you. Speak to us at engineered-composites.co.uk.