The revision of the standard series EN 13906 has been prepared by the initiative of the Association of the European Spring Federation ESF in order to correct technical errors in the published standards and to bring them up-to-date to the most current level of technology. The revision of the figures has not been part of the work. This is due to the absence of (mutual) data exchange. Nevertheless, the purchasers/customers can obtain the current data from the manufacturer. This European Standard applies to the calculation and design of cold and hot coiled cylindrical helical torsion springs with a linear characteristic, also called leg spring, made from round wire and bar of constant diameter. Cold coiled extension springs: - wire or bar diameter; d ≤ 20 mm - number of active coils; n ≥ 3 - spring index; 4 ≤ w ≤ 20. Hot coiled extension springs: - wire or bar diameter; d ≥10 mm - Number of active coils; n ≥ 3 - spring index; 4 ≤ w ≤ 12. This document (EN 13906-2:2013) has been prepared by Technical Committee CEN/TC 407 "Project Committee - Cylindrical helical springs made from round wire and bar - Calculation and design", the secretariat of which is held by AFNOR (France). The responsible national mirror committee is NA 026-00-01 AA "Federn" ("Springs") of the Springs, Stamped Parts and Moulded Parts Standards Committee (NAFS) at DIN, the German Institute for Standardization e. V. For more detailed information about the NAFS, please visit www.nafs.din.de.