If you are specifying structural GRP, you will come across BS EN 13706. It is the European standard that sets the minimum requirements for pultruded GRP profiles used in load-bearing applications. This guide explains what the standard covers, the difference between the E17 and E23 grades, and how to use it when specifying our GRP pultruded profiles.
What is BS EN 13706?
BS EN 13706 applies to pultruded profiles for structural purposes, meaning applications where load-bearing performance is the main design criterion and the profile forms part of a load-bearing system. It specifies minimum requirements for the quality, tolerances, strength, stiffness and surface finish of structural profiles, and the test methods used to verify them.
The two grades: E17 and E23
The standard defines two grades. The number is the minimum full-section flexural modulus in gigapascals: E17 requires at least 17 GPa and E23 at least 23 GPa. In practice, profiles with a wall thickness between 3mm and 5mm tend to meet E17, while those over 5mm meet the higher E23 grade. E17 suits secondary or lightly loaded applications; E23 is the grade to specify for primary structural elements, access platforms and walkway frames.
Minimum properties for the E23 grade
| Property | E23 minimum |
|---|---|
| Longitudinal flexural strength | 240 MPa |
| Longitudinal flexural modulus | 23 GPa |
| Longitudinal tensile strength | 240 MPa |
| Longitudinal tensile modulus | 23 GPa |
| Interlaminar shear strength | 25 MPa |
| Pin bearing strength (long. / trans.) | 150 MPa / 70 MPa |
| Glass content (by weight) | 60% minimum |
| Water absorption at 24 hours | 1.0% maximum |
How to use it when specifying
State the grade you need (usually E23 for anything structural), and ask your supplier to confirm the profile meets it. For load-bearing frames, platforms and walkways, E23 gives the stiffness and strength to keep deflection within limits. Browse our pultruded profiles, or for open mesh flooring see our load and span tables. If you are unsure which grade or section suits your project, call 01480 570001 or email info@gratingdirect.co.uk.
Frequently asked questions
What is the difference between E17 and E23 GRP?
The grade is the minimum full-section flexural modulus: E17 is 17 GPa and E23 is 23 GPa. E23 is stiffer and stronger and is used for structural and load-bearing applications, while E17 suits lighter, secondary uses.
Which grade should I specify?
For primary structural elements, platforms and walkway frames, specify E23. E17 may be acceptable for non-structural or lightly loaded secondary applications.
This guide summarises BS EN 13706 for general information. Always confirm the current standard and your design with a suitably qualified engineer for structural applications.
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