ISO 22201-2:2013
(Main)Lifts (elevators), escalators and moving walks — Programmable electronic systems in safety related applications — Part 2: Escalators and moving walks (PESSRAE)
Lifts (elevators), escalators and moving walks — Programmable electronic systems in safety related applications — Part 2: Escalators and moving walks (PESSRAE)
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 refe
Ascenseurs, escaliers mécaniques et trottoirs roulants — Systèmes électroniques programmables dans les applications liées à la sécurité — Partie 2: Escaliers mécaniques et trottoirs roulants
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 22201-2
First edition
2013-03-15
Lifts (elevators), escalators and
moving walks — Programmable
electronic systems in safety related
applications —
Part 2:
Escalators and moving walks (PESSRAE)
Ascenseurs, escaliers mécaniques et trottoirs roulants — Systèmes
électroniques programmables dans les applications liées à la sécurité —
Partie 2: Escaliers mécaniques et trottoirs roulants
Reference number
ISO 22201-2:2013(E)
©
ISO 2013
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ISO 22201-2:2013(E)
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ISO 22201-2:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Conformance . 2
3 Normative references . 2
4 Terms and definitions . 3
5 Symbols and abbreviated terms . 6
6 Requirements . 6
6.1 General . 6
6.2 Extended application of this International Standard . 7
6.3 Safety function SIL requirements . 7
6.4 SIL relevant and non-SIL relevant safe state requirements . 9
6.5 Implementation and demonstration requirements for verification of SIL compliance .13
Annex A (normative) Techniques and measures to implement, verify, and maintain
SIL compliance .14
Annex B (informative) Applicable escalator and moving walk codes, standards, and laws .17
Annex C (informative) Example of risk reduction decision table .23
Bibliography .24
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ISO 22201-2:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 178, Lifts, escalators and moving walks.
ISO 22201 consists of the following parts, under the general title Lifts (elevators), escalators and moving
walks — Programmable electronic systems in safety-related applications:
— Part 2: Escalators and moving walks (PESSRAE)
— Part 3: Life cycle guideline for Programmable Electronic Systems related to PESSRAL and PESSRAE
[Technical Report]
When revised, ISO 22201:2009, Lifts (elevators) — Design and development of programmable electronic
systems in safety-related applications for lifts (PESSRAL), will become Part 1.
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ISO 22201-2:2013(E)
Introduction
Systems comprised of electrical and/or electronic components have been used for many years to
perform safety functions in most application sectors. Computer-based systems, generically referred to as
programmable electronic systems (PES), are being used in many application sectors to perform non-safety
functions and, increasingly, to perform safety functions. If computer system technology is to be effectively
and safely exploited, it is essential that those responsible for making decisions have sufficient guidance
on the safety aspects on which to make these decisions. In most situations, safety is achieved by a number
of protective systems that rely on many technologies (for example mechanical, hydraulic, pneumatic,
electrical, electronic, programmable electronic). Any safety strategy must therefore consider not only
all the elements within an individual system (for example sensors, controlling devices and actuators) but
also all the safety-related sub-systems making up the total combination of safety-related systems.
This International Standard is based upon the guidelines provided in the generic International Electro-
technical Commission (IEC) Standard IEC 62061 and Comité Européen de Normalisation (CEN) Standard
EN 115-1:2008.
The requirements given in this International Standard recognize the fact that the product family covers a
total range of passenger and goods/passenger escalators and moving walks used in residential buildings,
offices, hospitals, hotels, industrial plants, etc. This International Standard is the product family standard
for escalators and moving walks and takes precedence over all aspects of the generic standard.
This International Standard sets out the product specific requirements for systems comprised of
programmable electronic components and programmable electronic systems (PES) that are used to perform
safety functions in escalators and moving walks. This International Standard has been developed in order
that consistent technical and performance requirements and rational be specified for Programmable
Electronic System in Safety-Related Application for Escalators and moving walks (PESSRAE).
Risk analysis, terminology, and technical solutions have been considered taking into account the
methods of the IEC 61508 series of standards. The risk analysis of each safety function specified in
Table 1 resulted in the classification of electric safety functions applied to PESSRAE. Tables 1 and 2 give
the safety integrity level and functional requirements, respectively, for each electric safety function.
The safety integrity levels (SIL) specified in this International Standard may also be applied to other
technologies used to satisfy the safety functions specified in this International Standard.
Harmonization with national escalator and moving walk norms:
Application of this International Standard:
The application of this International Standard is intended to be by reference within a national escalator
and moving walk norm such as escalator and moving walk codes, standards, or laws. There are three
reasons for this.
— To allow selective reference by national norms to specific escalator and moving walk safety functions
described in this International Standard. Not all escalator and moving walk safety functions
identified in this International Standard are called out in every national norm.
— To allow for future harmonization of national norms with escalator and moving walk safety
functions identified in this International Standard. Because there exist some differences in the
requirements for fulfilment of the safety objective of national escalator and moving walk norms and
in national practice of escalator and moving walk use and maintenance, there are instances where
the requirements for escalator and moving walk safety functions described in this International
Standard are based on the consensus work and agreement by the ISO committee responsible for this
International Standard. National bodies may choose to selectively harmonize with those escalator
and moving walk safety functions that differ in the requirements called for by the existing national
norm in future norm revisions.
— To allow for the application of this International Standard where escalator and moving walk safety
functions are new or deviate from those specified in this International Standard. More and more,
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ISO 22201-2:2013(E)
national escalator and moving walk legislations are moving to performance based requirements.
For this reason the development of new or different escalator and moving walk safety functions
can be foreseen in product specific applications. For those who require escalator and moving walk
safety functions that are new or different from those specified in this International Standard,
this International Standard provides a verifiable method to establish the necessary level of safety
integrity for those functions.
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INTERNATIONAL STANDARD ISO 22201-2:2013(E)
Lifts (elevators), escalators and moving walks —
Programmable electronic systems in safety related
applications —
Part 2:
Escalators and moving walks (PESSRAE)
1 Scope
1.1 This International Standard is applicable to the product family of escalators and moving walks used
in residential buildings, offices, hospitals, hotels, industrial plants, etc. This International Standard 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). This International Standard is applicable
for escalator and moving walk safety functions that are identified in escalator and moving walk codes,
standards, or laws that reference this International Standard for PESSRAE application. The safety integrity
levels (SILs) specified in this International Standard 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.
1.2 This International Standard is also applicable for the application of PESSRAE that are new or deviate
from those described in this International Standard.
1.3 The requirements of this International Standard 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, this International Standard:
a) uses safety integrity levels (SIL) for specifying the target failure rate for the safety functions to be
implemented by the PESSRAE;
b) 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;
c) 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;
d) defines the relationship between this International Standard and IEC 61508 and defines the
relationship between this International Standard and the EMC Standard for Escalators and moving
walks on immunity, ISO 22200;
e) outlines the relationship between escalator and moving walk safety functions and their safe-
state conditions;
f) 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;
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ISO 22201-2:2013(E)
g) 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;
h) provides requirements relating to the hardware and software safety validation;
i) establishes the safety integrity levels for specific escalator and moving walk safety functions;
j) specifies techniques/measures required for achieving the specified safety integrity levels;
k) defines a maximum level of performance (SIL 3) which can be achieved for a PESSRAE according to
this International Standard and defines a minimum level of performance (SIL 1).
1.4 This International Standard does not cover:
a) hazards arising from the PES equipment itself such as electric shock etc.;
b) 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 this International Standard;
c) 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 this International Standard.
2 Conformance
To conform to this International Standard, it shall be shown that each of the requirements outlined in
Clause 6 has been satisfied to the defined criteria and therefore the clause objective(s) has(have) been met.
3 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
IEC 61508-1, Functional safety of electrical/electronic/programmable electronic safety-related systems —
Part 1: General Requirements
IEC 61508-2, Functional safety of electrical/electronic/programmable electronic safety-related systems —
Part 2: Requirements for electrical/electronic/programmable/electronic safety-related systems
IEC 61508-3, Functional safety of electrical/electronic/programmable electronic safety-related systems —
Part 3: Software requirements
IEC 61508-4, Functional safety of electrical/electronic/programmable electronic safety-related systems —
Part 4: Definitions and abbreviations
IEC 61508-5, Functional safety of electrical/electronic/programmable electronic safety-related systems —
Part 5: Example of methods for the determination of Safety Integrity Levels
ISO 22200, Electromagnetic compatibility — Product family standard for lifts, escalators and moving
walks — Immunity
IEC 61249-2-1, Materials for printed boards and other interconnecting structures - Part 2-1: Reinforced base
materials, clad and unclad - Phenolic cellulose paper reinforced laminated sheets, economic grade, copper clad
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ISO 22201-2:2013(E)
4 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61508-4 apply, except that the
definitions in this International Standard take precedence over those in the generic standard.
4.1
manually operated stopping device
stopping device which is intentionally, by human intervention, actuated and de-actuated
EXAMPLE toggle switch, mushroom type, hand operated switches
4.2
non-manually operated stopping device
stopping device which is automatically actuated or de-actuated due to human intervention or detection
4.3
non-SIL relevant safe-state requirement
required response to the actuation of a SIL rated safety function where the function performing this
response is not required to be SIL rated
Note 1 to entry: See Figure 4 and Table 2.
4.4
programmable electronic system
PES
system for control, protection or monitoring based on one or more programmable electronic devices,
including all elements of the system such as power supplies, sensors and other input devices, data
highways and other communication paths, and actuators and other output devices
Note 1 to entry: See Figure 1.
Note 2 to entry: A PES may perform functions that fulfil requirements for SIL rated and non-SIL rated function(s).
The SIL rating of a function is only required to consider that portion of PES that perform the SIL relevant functional
requirements.
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ISO 22201-2:2013(E)
Extent of PES
Communications
Input interfaces Output interfaces
(for example, D-A (for example, D-A
Converters) Converters)
Programmable
electronics (PE)
(see note)
Output devices/inal
Input devices
elements
(for example, sensors)
(for example, actuators)
IEC 32 45/02
NOTE The programmable electronics are shown centrally located but could exist at several places in the PES.
Figure 1 — Basic PES structure
4.5
Programmable Electronic Systems in Safety-Related Applications for Escalators and moving walks
PESSRAE
application of a software-based PES in a safety-related system for escalators and moving walks
4.6
proof test
periodic test performed to detect failures in a safety-related system
Note 1 to entry: For example, where separate channels are used; these tests are done for each channel separately.
4.7
safety circuit
total combination of safety devices that fulfil all or a group of escalator and moving walk safety functions
Note 1 to entry: See Figure 2.
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ISO 22201-2:2013(E)
Safety Device 1 Safety Device 2
Function 1 Function 2
All or a group of
required lift
safety functions
(see Table 1)
Safety Device n Safety Device (n + 1)
Function n Function (n + 1)
Figure 2 — Safety chain
4.8
safety device
part of the safety-related system, including necessary control circuits, that has been designated to
achieve, in its own right, an escalator and moving walk safety function and may consist of PES elements
and non-PES elements
Note 1 to entry: See Figure 3 and Table 1.
PES elements Non-PES elements
Figure 3 — Safety Device
4.9
safety function
function to be implemented by a safety-related system, which is intended to achieve or maintain a safe-
state of the escalator and moving walk, with respect to a specific hazardous event
Note 1 to entry: See Table 1.
Note 2 to entry: A safety function may include non-SIL relevant requirements, see Table 2.
4.10
safety-related system
consists of one or more safety devices performing one or more safety functions that may be based
on programmable electronic systems (PES), electrical, electronic and/or mechanical elements of the
escalator and moving walk
Note 1 to entry: The term includes all the hardware, software and supporting services (for example, power
supplies) necessary to carry out the specified safety function (sensors, other input devices, final elements
(actuators) and other output devices are therefore included in the safety-related system).
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ISO 22201-2:2013(E)
4.11
safety integrity level
SIL
discrete level (one out of a possible four) for specifying the safety integrity requirements of the safety
functions to be allocated to the programmable electronic safety-related system, where safety integrity
level 4 has the highest level of safety integrity and safety integrity level 1 has the lowest. The SIL is
indicative of a failure rate that includes all causes of failures (both random hardware failures and
systematic failures), which lead to an unsafe state, for example hardware failures, software induced
failures and failures due to electrical interference
Note 1 to entry: In the context of this International Standard, SIL 3 is the highest safety integrity level that is
applied to escalators and moving walks.
4.12
SIL Relevant Safe-State Requirement
part of the safety-related system where the specified SIL of the function is required to be met
Note 1 to entry: See Figure 4 and Table 2.
Non-SIL relevant
SIL relevant safe-state
safe-state requirement(s)
requirement(s)
Figure 4 — Escalator and moving walk safety function
4.13
system reaction time
sum of the following two values:
a) the time period between the occurrence of a fault in the PESSRAE and the initiation of the
corresponding action on the escalator and moving walk;
b) the time period for the escalator and moving walk to respond to the action, maintaining a safe state.
5 Symbols and abbreviated terms
PCB Printed Circuit Board
6 Requirements
6.1 General
6.1.1 Table 1 defines the safety function names, the associated escalator and moving walk functional
description, applicable escalator and moving walk type and required SIL for the SIL relevant part of the
safety function.
NOTE Safety functions refer to those escalator and moving walk functions that are identified in codes,
standards and laws that reference this International Standard for PESSRAE application. (See B.1).
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ISO 22201-2:2013(E)
6.1.2 Table 2 defines the safe-state requirements when the safety functions in Table 1 are actuated. If a
safety function actuates, the safety function shall cause the escalator and moving walk system to revert to
the safe-state conditions specified by the requirements of Table 2.
6.1.3 PESSRAE shall consider the reaction time of the escalator and moving walk to respond to the
safety function and internal fault detection in the necessary time to achieve the safe-state condition
without hazard. Methods that fulfil internal fault detection must consider the necessary system reaction
time required by the SIL.
NOTE For example, if an internal fault is detected by comparison of data in a 2-channel system within the
time necessary to meet the system reaction time, then a variable memory range test need not be completed within
the system reaction time because safety integrity is verified by the 2-channel design.
6.2 Extended application of this International Standard
The following requirements are provided to verify SILs and safe-state conditions for escalator and
moving walk safety functions that are new or deviate from the requirements provided in 6.3 and 6.4, or
are referenced by codes and standards not harmonized with the requirements of codes, standards, or
laws referenced in B.1.
6.2.1 Risk assessment
Where alternatives to the requirements of 6.3 and/or 6.4 are sought, methods for the determination of
the required safety integrity level shall be performed according to IEC 61508-5 or IEC/EN 62061. The
same methods shall be used to establish rationale for a new PESSRAE function and corresponding SIL
or a revised PESSRAE function and/or SIL that deviate from the requirements of 6.3 and 6.4. The mean
target failure frequency for the worst-case severity of any single potential consequence hazard scenario
−7
shall not exceed a frequency of 5 × 10 per year. See also Annex C.
6.2.2 Limits for specifying SIL for PESSRAE
Target failure measures required for specifying a PES in a escalator and moving walk safety-related
function shall be no less than a SIL 1 and no greater than SIL 3. If a target failure measure requires
higher than SIL 3, consideration should be made to redesign the system such that the required target
failure measure shall be satisfied with SIL 3 or less. If a SIL lower than SIL 1 is required, a non-SIL rated
PES may be used but shall not be classified as a PESSRAE. No PESSRAE shall have a SIL of less than SIL 1
even if it is applied to a safety function requiring less than SIL 1.
Applications that require the use of a single safety function of safety integrity level 4 are not typically
required in the escalator and moving walk industry. Such applications shall be avoided because of the
difficulty of achieving and maintaining such high levels of performance throughout the life cycle of
the safety device. If the analysis results in a safety integrity level of 4 or higher being assigned to an
escalator and moving walk safety function, consideration shall be given to changing the process design
in such a way that it becomes more inherently safe or by adding additional layers of protection. These
enhancements could perhaps then reduce safety integrity level requirements for the escalator and
moving walk safety function. If the safety integrity level cannot be reduced, the target failure measure
for the safety function shall be distributed across multiple PESSRAE of SIL 3 or less that are sufficiently
independent, and certified in the application.
6.2.3 Safe-state requirements
For escalator and moving walk safety functions that are new or differ from those specified in 6.3 and 6.4, the
designer shall identify the safe-state requirements in a manner similar to how they are described in Table 2.
6.3 Safety function SIL requirements
Table 1 provides the required SIL for each escalator and moving walk safety function. For further
information, see Table B.1.
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ISO 22201-2:2013(E)
Table 1 — Safety function SIL requirements
Id. No. Escalator and moving walk Functional description SIL
safety function
1 Check for excessive speed Detect overspeed of the escalator or moving walk and 2
remove power from machine motor and brake before
the speed exceeds 20 % of rated speed.
2 Check for unintentional Detect for unintended reversal of travel when oper- 2
reversal of the direction of ated in the ascending direction
travel
3 Check for the closing of the Detect that the auxiliary brake has actuated 1
auxiliary brake
4 Check Broken Step-Chain Detect the step chain is broke 1
Device
5 Check Extension or reduc- Detect extension or reduction of the distance between 1
tion of the distance between the driving and return devices
the driving and return
devices
6 Check Comb-Step Impact Detect displacement of comb 1
Devices
7 Check for Egress Restriction Detect obstruction or barrier at the egress 2
Device
8 Check for objects entrapped Detect objects or body parts entering the handrail 1
in the handrail entry entry
9 Check for the sagging of step Detect a downward displacement of step or pallet at 2
or pallet the transitions and
...
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