**8. Design rules**

In general, for building applications in Europe the Eurocode is used. There is, however, no specific Eurocode dedicated to composites. In The Netherlands a specific recommendation for design with composites is available [16] but only for composites made from virgin materials. Nevertheless, the general methodology from the Eurocode can be followed irrespective of the origin of the raw materials from which it is built. This is described in the European standard EN 1990 [17]. In this standard, in Annex D (Design assisted by testing) it is described in what manner material properties can be determined using a test programme.

Based on extensive testing of EoL thermoset composites [18] to date the following conclusions can be made for the design with these materials made with re-used EoL thermoset composites:

• Design for long-term loading (creep) and fatigue should be avoided for parts solely consisting of re-used EoL composites in a product. For these load types continuous virgin fibre reinforcement must be incorporated into the product to ensure resistance to creep and fatigue.

• For design on stiffness and strength (with exclusion of creep and fatigue) design formulas can be used [16], with the conversion factor set to 0.9. It is required that re-used EoL composite is compatible with the virgin resin in which it is embedded (e.g. good adhesion) and that the virgin resin is resistant to the user conditions of the new product and is properly cured.
