This standard gives guidance on the procedure and information required to allow functional safety assessment to be carried out for the design of protective systems by the manufacturer. An additional purpose of this European Standard is to assist technical standardization committees responsible for specific families of protective systems in preparing safety standards. In this procedure the following information is to be taken into account in order to ensure a sufficient level of functional safety: the intended use, the possible operating faults, the reliability of protective systems, the misuse which can reasonably be anticipated. A sufficient level of functional safety is characterized by the following objectives: The system can stop an explosion at a very early stage or reduce the impact of an explosion to an acceptable level. In the event of faults, failures and/or interference 1) the capacity to function remains effective by use e. g. of fail safe techniques or redundancy. This European Standard does not cover identification of possible ignition sources which is covered by prEN 15198. This European Standard is only dealing with the functional behaviour of the protective system i.e. hazards caused by malfunctions, e. g. false activations are excluded. This standard specifies neither specific methods to analyse fault conditions, nor specific requirements for a given type of protective system (see EN 1127-1:2004, 6.5). It specifies the methodology of functional safety assessment. This standard provides advice for decision to be made for all types of protective systems referred to in 94/9/EC-Directive but does not provide means to prove the conformity of a given type of protective systems. NOTE Equipment is dealt with in another standard (prEN 15198) owing to the fact that the procedure and information required to allow ignition hazard assessment is different from the procedure above.