IEC 61810-2-1:2011 specifies reliability test procedures for electromechanical elementary relays when enhanced requirements for the verification of reliability apply. Particular provisions are given for relays incorporated in safety-related control systems of machinery in accordance with IEC 62061 and ISO 13849-1. For such relays Bsub10/sub values for dangerous failures (Bsub10d/sub values) are derived from the tests specified in this standard. This International Standard is only intended to be used in conjunction with IEC 61810-2.