ISO 22201-2:2013

ISO 22201-2:2013 is applicable to the product family of escalators and moving walks used in residential buildings, offices, hospitals, hotels, industrial plants, etc. It covers those aspects that need to be addressed when programmable electronic systems are used to carry out electric safety functions for escalators and moving walks (PESSRAE). It is applicable for escalator and moving walk safety functions that are identified in escalator and moving walk codes, standards, or laws that reference ISO 22201-2:2013 for PESSRAE application. The safety integrity levels (SILs) specified in ISO 22201-2:2013 are understood to be valid for PESSRAE application in the context of the referenced escalator and moving walk codes, standards, and laws in Annex B.
ISO 22201-2:2013 is also applicable for the application of PESSRAE that are new or deviate from those described in ISO 22201-2:2013.
The requirements of ISO 22201-2:2013 regarding electrical safety/protective devices are such that the possibility of a failure of an electric safety/protective device complying with all the requirements of the standard needs not to be taken into consideration.
In particular, ISO 22201-2:2013:

uses safety integrity levels (SIL) for specifying the target failure rate for the safety functions to be implemented by the PESSRAE;
specifies the requirements for achieving safety integrity for a function but does not specify who is responsible for implementing and maintaining the requirements (for example, designers, suppliers, owner/operating company, contractor); this responsibility is assigned to different parties according to safety planning and national regulations;
applies to PES used in escalator and moving walk applications that meet the minimum requirements of a recognized escalator and moving walk standards such as EN 115, ASME A17.1/CSA B44, or escalator and moving walk laws such as The Japan Building Standard Law Enforcement Order For Elevator and Escalator;
defines the relationship between ISO 22201-2:2013 and IEC 61508 and defines the relationship between ISO 22201-2:2013 and the EMC Standard for Escalators and moving walks on immunity, ISO 22200;
outlines the relationship between escalator and moving walk safety functions and their safe-state conditions;
applies to phases and activities that are specific to design of hardware and software but not those phases and activities which occur post design, for example sourcing and manufacturing;
requires the manufacturer of the PESSRAE to provide instructions that specify what is necessary to maintain the integrity of the PESSRAE (instruction manual) for organization carrying out the assembly, connections, adjustment and maintenance of the escalators and moving walks;
provides requirements relating to the hardware and software safety validation;
establishes the safety integrity levels for specific escalator and moving walk safety functions;
specifies techniques/measures required for achieving the specified safety integrity levels;
defines a maximum level of performance (SIL 3) which can be achieved for a PESSRAE according to ISO 22201-2:2013 and defines a minimum level of performance (SIL 1).

ISO 22201-2:2013 does not cover:

hazards arising from the PES equipment itself such as electric shock etc.;
the concept of fail-safe that may be of value when the failure modes are well defined and the level of complexity is relatively low. The concept of fail-safe was considered inappropriate because of the full range of complexity of PESSRAE that are within the scope of ISO 22201-2:2013;
other relevant requirements necessary for the complete application of a PESSRAE in a escalator and moving walk safety function such as system integration specifications, temperature and humidity, the mechanical construction, mounting and labelling of switches, actuators, or sensors that contain PESSRAE. These requirements are to be carried out in accordance with the national escalator and moving walk norm that references ISO 22201-2:2013.