IEC 63044-4:2021

Home and building electronic systems (HBES) and building automation and control systems (BACS) - Part 4: General functional safety requirements for products intended to be integrated in HBES and BACS

IEC 63044-4:2021 provides the functional safety requirements for HBES/BACS.
In addition, it defines functional safety requirements for the interface of equipment intended to be connected to an HBES/BACS network. It does not apply to interfaces to other networks.
This document does not provide functional safety requirements for safety-related systems.
This document does not provide requirements on data protection and security.

Systèmes électroniques pour les foyers domestiques et les bâtiments (HBED) et systèmes de gestion technique du bâtiment (SGTB) - Partie 4: Exigences générales de sécurité fonctionnelle pour les produits destinés à être intégrés dans les HBES et SGTB

L'IEC 63044-4:2021 spécifie les exigences de sécurité fonctionnelle pour HBES/SGTB.
De plus, elle spécifie des exigences de sécurité fonctionnelle relatives à l'interface des équipements destinés à être connectés à un réseau HBES/SGTB. Elle ne s'applique pas aux interfaces avec d'autres réseaux.
Le présent document ne spécifie pas d’exigences de sécurité fonctionnelle des systèmes relatifs à la sécurité.
Le présent document ne spécifie pas d’exigences relatives à la protection et la sécurité des données.

General Information

• Status: Published
• Publication Date: 28-Jun-2021
• ICS: 29.120.01 - Electrical accessories in general
• ICS: 29.120.99 - Other electrical accessories
• Technical Committee: TC 23 - Electrical accessories
• Current Stage: PPUB - Publication issued
• Completion Date: 29-Jun-2021

Standards Content (Sample)

IEC 63044-4
Edition 1.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Home and building electronic systems (HBES) and building automation and
control systems (BACS) –
Part 4: General functional safety requirements for products intended to be
integrated in HBES and BACS
Systèmes électroniques pour les foyers domestiques et les bâtiments (HBES) et
systèmes de gestion technique du bâtiment (SGTB) –
Partie 4: Exigences générales de sécurité fonctionnelle pour les produits
destinés à être intégrés dans les HBES et SGTB
IEC 63044-4:2021-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 63044-4
Edition 1.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Home and building electronic systems (HBES) and building automation and
control systems (BACS) –
Part 4: General functional safety requirements for products intended to be
integrated in HBES and BACS
Systèmes électroniques pour les foyers domestiques et les bâtiments (HBES) et
systèmes de gestion technique du bâtiment (SGTB) –
Partie 4: Exigences générales de sécurité fonctionnelle pour les produits
destinés à être intégrés dans les HBES et SGTB
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.01; 29.120.99 ISBN 978-2-8322-9898-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 63044-4:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 6

4 General requirements .................................................................................................... 10

4.1 General ................................................................................................................. 10

4.2 Method of establishment of the requirements ........................................................ 10

4.2.1 General ......................................................................................................... 10

4.2.2 HBES/BACS application environment ............................................................ 11

4.2.3 Sources of hazards ........................................................................................ 11

4.2.4 Hazardous events .......................................................................................... 11

4.2.5 Derivation of requirements ............................................................................. 11

5 Requirements for functional safety ................................................................................. 12

5.1 General ................................................................................................................. 12

5.2 Power feeding ....................................................................................................... 12

5.3 Life time ................................................................................................................ 13

5.4 Reasonably foreseeable misuse ............................................................................ 13

5.5 Software and communication ................................................................................ 13

5.6 Remote operations ................................................................................................ 15

5.6.1 General recommendations ............................................................................. 15

5.6.2 Within a single building or in its immediate vicinity ......................................... 15

5.6.3 From outside the building .............................................................................. 15

5.6.4 Management .................................................................................................. 16

Annex A (informative) Example of a method for the determination of safety integrity

levels .................................................................................................................................... 17

A.1 General ................................................................................................................. 17

A.2 As low as reasonably practicable (ALARP) and tolerable risk concepts ................. 17

Annex B (informative) Hazards and development of necessary functional safety

requirements ......................................................................................................................... 19

Annex C (informative) Some examples of non-safety-related HBES/BACS applications ....... 27

C.1 General ................................................................................................................. 27

C.2 Examples of non-safety-related HBES/BACS applications ..................................... 27

C.2.1 Example 1: Oven ........................................................................................... 27

C.2.2 Example 2: Devices presenting a high potential risk of hazard ....................... 27

C.2.3 Example 3: Mains plugs, socket outlets and circuits ....................................... 28

C.2.4 Example 4: Water temperature adjustment .................................................... 28

Bibliography .......................................................................................................................... 29

Figure A.1 – Risk reduction – General concept ..................................................................... 17

Table 1 – Requirements for avoiding inadvertent operations and possible ways to

achieve them ........................................................................................................................ 16

Table A.1 – Example of risk classification of accidents.......................................................... 18

Table A.2 – Interpretation of risk classes .............................................................................. 18

Table B.1 – Requirements and/or risk reduction measures .................................................... 19

---------------------- Page: 4 ----------------------
IEC 63044-4:2021 © IEC 2021 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOME AND BUILDING ELECTRONIC SYSTEMS (HBES) AND
BUILDING AUTOMATION AND CONTROL SYSTEMS (BACS) –
Part 4: General functional safety requirements for
products intended to be integrated in HBES and BACS
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 63044-4 has been prepared by IEC technical committee 23: Electrical accessories. It is an

International Standard.
The text of this International Standard is based on the following documents:
FDIS Report on voting
23/973/FDIS 23/975/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.
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– 4 – IEC 63044-4:2021 © IEC 2021

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/standardsdev/publications.

A list of all parts in the IEC 63044 series, published under the general title Home and Building

Electronic Systems (HBES) and Building Automation and Control Systems (BACS), can be

found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 6 ----------------------
IEC 63044-4:2021 © IEC 2021 – 5 –
INTRODUCTION

Functional safety includes the safe operation of devices and appliances ("products") when

installed into and operating on a communications network in a home or building ("premises").

This document specifies installation, control, operating, and failure mode procedures to

enhance the functional safety of devices installed in homes and buildings. A device functions

safely if it causes no harm while operating and performing an intended task. Such devices might

not operate safely due to installation or control problems.

The growing use of home and building networks to interconnect devices introduces additional

challenges to maintaining functional safety because of possible device interactions. Therefore,

this document addresses the risks of connecting devices to a home or building network, which

enables data exchanges and remote control from within the home or building.

Furthermore, if the home or building network is connected to a public network, control from

remote locations may be possible. Such control messages might originate from a smart phone

app, be sent through a mobile telephone network, routed to a building gateway, and sent via a

home or building network to a device communications interface. Thus, there are many

opportunities for such messages to be compromised. Remote access poses additional threats

to functional safety that are addressed in this document.

This document is part of IEC 63044 series and applies to home and building electronic systems

(HBES/BACS).

This document applies to home and building electronic systems (HBES) in general and

specifically to systems conforming to the home electronic system (HES) family of ISO/IEC

standards.
HBES/BACS products in this document are for non-safety-related systems.

The intention of this document is to specify, as far as possible, all safety requirements for

HBES/BACS products in their life cycle.

This document specifies the general functional safety requirements for devices connected to a

home or building network following the principles of the basic standard for functional safety,

IEC 61508 (all parts). It covers functional safety issues related to device and device

installations. The requirements are based on a risk analysis in accordance with IEC 61508.

---------------------- Page: 7 ----------------------
– 6 – IEC 63044-4:2021 © IEC 2021
HOME AND BUILDING ELECTRONIC SYSTEMS (HBES) AND
BUILDING AUTOMATION AND CONTROL SYSTEMS (BACS) –
Part 4: General functional safety requirements for
products intended to be integrated in HBES and BACS
1 Scope

This part of IEC 63044 provides the functional safety requirements for HBES/BACS.

In addition, it defines functional safety requirements for the interface of equipment intended to

be connected to an HBES/BACS network. It does not apply to interfaces to other networks.

NOTE 1 An example of another network is a dedicated ICT network covered by IEC 62949.

This document does not provide functional safety requirements for safety-related systems.

NOTE 2 Examples of non-safety-related HBES/BACS applications are given in Annex C.

This document does not provide requirements on data protection and security.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.
IEC 60364 (all parts), Low-voltage electrical installations

IEC 63044-3:2017, Home and Building Electronic Systems (HBES) and Building Automation

and Control Systems (BACS) – Part 3: Electrical safety requirements

IEC 63044-5 (all parts), Home and Building Electronic Systems (HBES) and Building

Automation and Control Systems (BACS)

IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-

related systems

IEC 61709:2017, Electric components – Reliability – Reference conditions for failure rates and

stress models for conversion
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
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IEC 63044-4:2021 © IEC 2021 – 7 –
3.1
authentication

means for certifying that the entity sending a message is what or who it purports to be and

confirmation that the message is identical to that which was sent
3.2
authorisation

mechanism to ensure that the entity or person accessing information, functions or services has

the authority to do so
3.3
disturbed communication

communication in which for any reason a message being communicated is incomplete,

truncated, contains errors or has the correct format but delivers information which is outside

the range of expected parameters for such a message
3.4
functional safety

freedom from unacceptable risk of harm due to the operation of an HBES/BACS, including that

resulting from:
1) normal operation,
2) reasonably foreseeable misuse,
3) failure,
4) temporary disturbances,

and forming part of the overall safety relating to the EUC (equipment under control, see 3.17)

and the EUC control system that depends on the correct functioning of the E/E/PE

(electrical/electronic/programmable electronic) safety-related systems and other risk reduction

measures

Note 1 to entry: The definitions of "functional safety" given in IEC/TR 61000-2-1 and IEC 61000-1-2 are taken into

account.

[SOURCE: IEC 61508-4:2010, 3.1.12, modified – Addition of introduction and items 1 to 4 of

list, text in brackets, and note.]
3.5
Hamming distance
number of bits in which two binary codes differ
3.6
harm

physical injury or damage to the health of people either directly or indirectly as a result of

damage to property or the environment

[SOURCE: IEC 61508-4:2010, 3.1.1, modified – Addition of "either directly or indirectly as a

result of".]
3.7
hazard
potential source of harm

Note 1 to entry: The term includes danger to persons arising within a short time scale (for example, fire and

explosion) and also those that have a long-term effect on a person's health (for example, release of a toxic

substance).
[SOURCE: IEC 61508-4:2010, 3.1.2]
---------------------- Page: 9 ----------------------
– 8 – IEC 63044-4:2021 © IEC 2021
3.8
hazardous event
situation which results in harm on normal operation or abnormal condition

Note 1 to entry: Whether or not a hazardous event results in harm depends on whether people, property or the

environment are exposed to the consequence of the hazardous event and, in the case of harm to people, whether

any such exposed people can escape the consequences of the event after it has occurred.

Note 2 to entry: Adapted from IEC 61508-4:2010, 3.1.4.
3.9
product

device in the form of hardware or firmware, and its associated software and configuration tools

3.10
product documentation

manufacturer's installation and operations literature, such as manufacturer's catalogue, leaflet

and other printed or electronic product information
3.11
safety-related system
designated system that both

– implements the required safety functions necessary to achieve or maintain a safe state for

the EUC, and

– is intended to achieve, on its own or with other E/E/PE safety-related systems and other

technology risk reduction measures, the necessary safety integrity for the required safety

functions

Note 1 to entry: The term refers to those systems, designated as safety-related systems, that are intended to

achieve, together with the other risk reduction measures, the necessary risk reduction in order to meet the required

tolerable risk. See also Annex A of IEC 61508-5.

Note 2 to entry: Safety-related systems are designed to prevent the EUC from going into a dangerous state by

taking appropriate action on detection of a condition which may lead to a hazardous event. The failure of a safety-

related system would be included in the events leading to the determined hazard or hazards. Although there may be

other systems having safety functions, it is the safety-related systems that have been designated to achieve, in their

own right, the required tolerable risk. Safety-related systems can broadly be divided into safety-related control

systems and safety-related protection systems.

Note 3 to entry: Safety-related systems may be an integral part of the EUC control system or may interface with the

EUC by sensors and/or actuators. That is, the required safety integrity level may be achieved by implementing the

safety functions in the EUC control system (and possibly by additional separate and independent systems as well)

or the safety functions may be implemented by separate and independent systems dedicated to safety.

Note 4 to entry: A safety-related system may

a) be designed to prevent the hazardous event (i.e. if the safety-related systems perform their safety functions then

no harmful event arises);

b) be designed to mitigate the effects of the harmful event, thereby reducing the risk by reducing the consequences;

c) be designed to achieve a combination of a) and b).

Note 5 to entry: A person can be part of a safety-related system. For example, a person could receive information

from a programmable electronic device and perform a safety action based on this information, or perform a safety

action through a programmable electronic device.

Note 6 to entry: A safety-related system 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).

Note 7 to entry: A safety-related system may be based on a wide range of technologies including electrical,

electronic, programmable electronic, hydraulic and pneumatic.

[SOURCE: IEC 61508-4:2010, 3.4.1, modified – The word "technology" has been added to the

definition.]
---------------------- Page: 10 ----------------------
IEC 63044-4:2021 © IEC 2021 – 9 –
3.12
safety integrity

probability of a safety-related system satisfactorily maintaining the required safety functions

under all the stated conditions within a stated period of time

Note 1 to entry: The higher the level of safety integrity, the lower the probability that the safety-related system will

fail to carry out the specified safety functions or will fail to adopt a specified state when required.

Note 2 to entry: There are four levels of safety integrity (see 3.5.8 of IEC 61508-4:2010).

Note 3 to entry: In determining safety integrity, all causes of failures (both random hardware failures and systematic

failures) that lead to an unsafe state should be included, for example hardware failures, software induced failures

and failures due to electrical interference. Some of these types of failure, in particular random hardware failures,

may be quantified using such measures as the average frequency of failure in the dangerous mode of failure or the

probability of a safety-related protection system failing to operate on demand. However, safety integrity also depends

on many factors that cannot be accurately quantified but can only be considered qualitatively.

Note 4 to entry: Safety integrity comprises hardware safety integrity and systematic safety integrity.

Note 5 to entry: This definition focuses on the reliability of the safety-related systems to perform the safety functions

(see IEV 192-01-24 for a definition of reliability).

[SOURCE: IEC 61508-4:2010, 3.5.4, modified – Deletion of "E/E/PE" from the definition, the

word "performing" has been replaced with "maintaining", "specified" has been replaced with

"required", and "of IEC 61508-4:2010" has been added to Note 2.]
3.13
safety integrity level
SIL

discrete level (one out of a possible four), corresponding to a range of safety integrity values,

where safety integrity level 4 has the highest level of safety integrity and safety integrity level 1

has the lowest

Note 1 to entry: The target failure measures (see 3.5.17) for the four safety integrity levels are specified in Tables 2

and 3 of IEC 61508-1:2010.

Note 2 to entry: Safety integrity levels are used for specifying the safety integrity requirements of the safety

functions to be allocated to the E/E/PE safety-related systems.

Note 3 to entry: A safety integrity level (SIL) is not a property of a system, subsystem, element or component. The

correct interpretation of the phrase "SIL n safety-related system" (where n is 1, 2, 3 or 4) is that the system is

potentially capable of supporting safety functions with a safety integrity level up to n.

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