ERA guide for application of the Common Safety Methods ... - Europa

European Railway AgencyGuide for the application of the CSM Regulation 2.4. Use of reference system and risk evaluation2.4.1. The proposer, with the support of other involved actors, shall analyse whether one ormore hazards are covered by a similar system that could be taken as a referencesystem.[G 1] Recital (4) of the Railway Safety Directive {Ref. 1} also encourages the application of similarreference systems for maintaining the safety levels of the Community rail system.2.4.2. A reference system shall satisfy at least the following requirements:(a) it has already been proven in-use to have an acceptable safety level and would stillqualify for acceptance in the Member State where the change is to be introduced;(b) it has similar functions and interfaces as the system under assessment;(c) it is used under similar operational conditions as the system under assessment;(d) it is used under similar environmental conditions as the system under assessment.[G 1] This sets out the conditions necessary in order to enable the control of one or severalhazards of the system under assessment by the comparison with similar reference systems.[G 2] Hazards could be identified where "similar reference systems" exist but, under specificcircumstances, the comparison with those may not be sufficient to ensure the safety of thesystem under assessment. Therefore, it is of prime importance to ensure that the systemunder assessment is used under similar functional, operational and environmental conditionsas the similar reference system. If this is not the case, another "similar reference system" orone of the other two risk acceptance principles can be used for controlling the risk to anacceptable level.[G 3] If the safety requirements from a reference system are used for the system underassessment, it is necessary to check also that the reference system still "qualifies foracceptance" in the Member State where the intended change is being introduced. It canhappen, for example, that the safety performance of the considered reference system is notappropriate for the system under assessment because it is based on out of date technology(i.e. old fashioned technology).2.4.3. If a reference system fulfils the requirements listed in point 2.4.2, then for the systemunder assessment:(a) the risks associated with the hazards covered by the reference system shall beconsidered as acceptable;(b) the safety requirements for the hazards covered by the reference system may bederived from the safety analyses or from an evaluation of safety records of thereference system;(c) these safety requirements shall be registered in the hazard record as safetyrequirements for the relevant hazards.[G 1] The hazards and associated risks that are covered by reference systems are implicitlyconsidered as acceptable, provided the conditions of application of reference systems insection 2.4.2 are fulfilled. This means that explicit risk acceptance criteria need not to bedefined for the hazards controlled by this principle. Reference: ERA/GUI/01-2008/SAF Version: 1.1 Page 41 of 54File Name: Guide_for_Application_of_CSM_V1.1.docEuropean Railway Agency ● Boulevard Harpignies, 160 ● BP 20392 ● F-59307 Valenciennes Cedex ● France ● Tel. +33 (0)3 27 09 65 00 ● Fax +33 (0)3 27 33 40 65 ● http://www.era.europa.eu