BS EN 13115:2020 pdf free.Windows一Classification of mechanical properties - Racking, torsion and operating forces. BS EN 13115 1 Scope This document provides a means of classifying the performance of opening windows according to their strength in resisting, where appropriate, racking load, static torsion and their manual operating forces.Special aspects such as those of burglar resistance are not covered.1) 2 Normative...