Information technology — Data centre facilities and infrastructures — Part 3: Power distribution

This document addresses power supplies to, and power distribution within, data centres based upon the criteria and classifications for “availability”, “physical security” and “energy efficiency enablement” within ISO/IEC 22237‑1. This document specifies requirements and recommendations for the following: a) power supplies to data centres; b) power distribution systems to all equipment within data centres; c) telecommunications infrastructure bonding; d) lightning protection; e) devices for the measurement of the power consumption and power quality characteristics at points along the power distribution system and their integration within management tools. Safety and electromagnetic compatibility (EMC) requirements are outside the scope of this document and are covered by other standards and regulations. However, information given in this document can be of assistance in meeting these standards and regulations. Conformance of data centres to the present document is covered in Clause 4. The use of the data centre stored energy or alternate sources to be used by the grid is not in the scope of this document and is for consideration in future specifications.

Technologie de l’information — Installation et infrastructures de centres de traitement de données — Partie 3: Distribution de puissance

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Published
Publication Date
04-Oct-2021
Current Stage
6060 - International Standard published
Start Date
05-Oct-2021
Completion Date
05-Oct-2021
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INTERNATIONAL ISO/IEC
STANDARD 22237-3
First edition
2021-10
Information technology — Data centre
facilities and infrastructures —
Part 3:
Power distribution
Technologie de l’information — Installation et infrastructures de
centres de traitement de données —
Partie 3: Distribution de puissance
Reference number
ISO/IEC 22237-3:2021(E)
© ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC 22237-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 22237-3:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms, definitions and abbreviated terms .............................................................................................................................. 2

3.1 Terms and definitions ...................................................................................................................................................................... 2

3.2 Abbreviated terms .............................................................................................................................................................................. 6

3.3 Symbols ......................................................................................................................................................................................................... 6

4 Conformance ............................................................................................................................................................................................................ 7

5 Power supply and distribution within data centres ...................................................................................................... 7

5.1 Functional elements........................................................................................................................................................................... 7

5.1.1 General ........................................................................................................................................................................................ 7

5.1.2 Power supply to the data centre ........................................................................................................................... 8

5.1.3 Power distribution within the data centre ................................................................................................. 9

5.2 Dimensioning of power distribution systems ......................................................................................................... 10

6 Availability ..............................................................................................................................................................................................................11

6.1 General requirements ................................................................................................................................................................... 11

6.2 Power supply ......................................................................................................................................................................................... 11

6.2.1 Capacity planning ........................................................................................................................................................... 11

6.2.2 Availability of the utility supply ........................................................................................................................ 13

6.2.3 Power quality ..................................................................................................................................................................... 14

6.2.4 Load presented to the utility supply.............................................................................................................. 15

6.2.5 Equipment ............................................................................................................................................................................. 15

6.2.6 Availability Class design options ...................................................................................................................... 17

6.3 Power distribution ...........................................................................................................................................................................23

6.3.1 Capacity planning ........................................................................................................................................................... 23

6.3.2 Power quality ..................................................................................................................................................................... 24

6.3.3 Equipment ............................................................................................................................................................................. 25

6.3.4 Availability Class design options ...................................................................................................................... 25

6.4 Incorporation of low voltage direct current distribution .............................................................................29

6.5 Additional considerations ......................................................................................................................................................... 29

6.5.1 Residual current measurement ..........................................................................................................................29

6.5.2 Lightning and surge protection .........................................................................................................................29

6.5.3 Segregation of power distribution cabling and information technology

cabling ....................................................................................................................................................................................... 30

6.6 Emergency power off (EPO)..................................................................................................................................................... 30

6.6.1 Requirements .....................................................................................................................................................................30

6.6.2 Recommendations..........................................................................................................................................................30

7 Physical security ...............................................................................................................................................................................................30

7.1 General ........................................................................................................................................................................................................30

7.2 Access........................................................................................................................................................................................................... 30

7.2.1 Power supply ........................................................................................................................................... ............................30

7.2.2 Power distribution .........................................................................................................................................................30

7.2.3 Attachment of unauthorized end-equipment ........................................................................................30

7.3 Internal environmental events ............................................................................................................................................. 31

7.3.1 Power supply ........................................................................................................................................... ............................ 31

7.3.2 Power distribution ....................................................................................................................................................... 31

7.4 External environmental events ............................................................................................................................................ 31

8 Energy efficiency enablement and power distribution ...........................................................................................31

8.1 General ........................................................................................................................................................................................................ 31

8.2 Granularity Level 1 .......................................................................................................................................................................... 32

iii
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ISO/IEC 22237-3:2021(E)

8.2.1 Requirements ..................................................................................................................................................................... 32

8.2.2 Recommendations..........................................................................................................................................................33

8.3 Granularity Level 2 .......................................................................................................................................................................... 33

8.3.1 Requirements ..................................................................................................................................................................... 33

8.3.2 Recommendations.......................................................................................................................................................... 33

8.4 Granularity Level 3 ..........................................................................................................................................................................34

8.4.1 Requirements .....................................................................................................................................................................34

8.4.2 Recommendations..........................................................................................................................................................34

8.5 Cabling infrastructure to support energy efficiency enablement .........................................................34

Bibliography .............................................................................................................................................................................................................................35

© ISO/IEC 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC 22237-3:2021(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that are

members of ISO or IEC participate in the development of International Standards through technical

committees established by the respective organization to deal with particular fields of technical

activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international

organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the

work.

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 document should be noted. This document was drafted in

accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or

www.iec.ch/members_experts/refdocs).

Attention is drawn to the possibility that some of the elements of this document may be the subject

of patent rights. ISO and IEC 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 (see www.iso.org/patents) or the IEC

list of patent declarations received (see patents.iec.ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see

www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 39, Sustainability, IT & Data Centres.

This first edition cancels and replaces the first edition (ISO/IEC TS 22237-3:2018), which has been

technically revised.
The main changes are as follows:

— availability requirements have been aligned with ISO/IEC 22237-1 and ISO/IEC 22237-4;

— figures have been updated.

A list of all parts in the ISO/IEC 22237 series can be found on the ISO and IEC websites.

Any feedback or questions on this document should be directed to the user’s national standards

body. A complete listing of these bodies can be found at www.iso.org/members.html and

www.iec.ch/national-committees.
© ISO/IEC 2021 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/IEC 22237-3:2021(E)
Introduction

The unrestricted access to internet-based information demanded by the information society has led to

an exponential growth of both internet traffic and the volume of stored/retrieved data. Data centres

are housing and supporting the information technology and network telecommunications equipment

for data processing, data storage and data transport. They are required both by network operators

(delivering those services to customer premises) and by enterprises within those customer premises.

Data centres need to provide modular, scalable and flexible facilities and infrastructures to easily

accommodate the rapidly changing requirements of the market. In addition, energy consumption

of data centres has become critical, both from an environmental point of view (reduction of carbon

footprint), and with respect to economic considerations (cost of energy) for the data centre operator.

The implementation of data centres varies in terms of:
a) purpose (enterprise, co-location, co-hosting or network operator facilities);
b) security level;
c) physical size; and
d) accommodation (mobile, temporary and permanent constructions).
NOTE Cloud services can be provided by all data centre types mentioned.

The needs of data centres also vary in terms of availability of service, the provision of security and

the objectives for energy efficiency. These needs and objectives influence the design of data centres in

terms of building construction, power distribution, environmental control, telecommunications cabling

and physical security. Effective management and operational information are required to monitor

achievement of the defined needs and objectives.

The ISO/IEC 22237 series specifies requirements and recommendations to support the various parties

involved in the design, planning, procurement, integration, installation, operation and maintenance of

facilities and infrastructures within data centres. These parties include:

1) owners, operators, facility managers, ICT managers, project managers, main contractors;

2) consultants, architects, building designers and builders, system and installation designers, auditors

and commissioning agents;
3) suppliers of equipment; and
4) installers, maintainers.

At the time of publication of this document, the ISO/IEC 22237 series comprises the following

documents:

— ISO/IEC 22237-1, Information technology — Data centre facilities and infrastructures — Part 1:

General concepts;

— ISO/IEC TS 22237-2, Information technology — Data centre facilities and infrastructures — Part 2:

Building construction;

— ISO/IEC 22237-3 (this document), Information technology — Data centre facilities and infrastructures —

Part 3: Power distribution;

— ISO/IEC 22237-4, Information technology — Data centre facilities and infrastructures — Part 4:

Environmental control;

— ISO/IEC TS 22237-5, Information technology — Data centre facilities and infrastructures — Part 5:

Telecommunications cabling infrastructure;
© ISO/IEC 2021 – All rights reserved
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ISO/IEC 22237-3:2021(E)

— ISO/IEC TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:

Security systems;

— ISO/IEC TS 22237-7: Information technology — Data centre facilities and infrastructures — Part 7:

Management and operational information.

The inter-relationship of the specifications within the ISO/IEC 22237 series is shown in Figure 1.

Figure 1 — Schematic relationship between the ISO/IEC 22237 series of documents

ISO/IEC TS 22237-2 to ISO/IEC TS 22237-6 specify requirements and recommendations for particular

facilities and infrastructures to support the relevant classification for “availability”, “physical security”

and “energy efficiency enablement” selected from ISO/IEC 22237-1.

This document, ISO/IEC 22237-3, addresses facilities and infrastructures for power supplies to, and

power distribution within, data centres together with the interfaces for monitoring the performance

of those facilities and infrastructures in line with ISO/IEC TS 22237-7 (in accordance with the

requirements of ISO/IEC 22237-1). The line diagrams used in certain figures are not intended to replace

the more familiar electrical circuit diagrams associated with power supply and distribution systems,

which are included where relevant.

ISO/IEC TS 22237-7 addresses operational and management information (in accordance with the

requirements of ISO/IEC 22237-1).

This document is intended for use by and collaboration between architects, building designers and

builders, and system and installation designers.

The ISO/IEC 22237 series does not address the selection of information technology and network

telecommunications equipment, software and associated configuration issues.
vii
© ISO/IEC 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO/IEC 22237-3:2021(E)
Information technology — Data centre facilities and
infrastructures —
Part 3:
Power distribution
1 Scope

This document addresses power supplies to, and power distribution within, data centres based upon

the criteria and classifications for “availability”, “physical security” and “energy efficiency enablement”

within ISO/IEC 22237-1.
This document specifies requirements and recommendations for the following:
a) power supplies to data centres;
b) power distribution systems to all equipment within data centres;
c) telecommunications infrastructure bonding;
d) lightning protection;

e) devices for the measurement of the power consumption and power quality characteristics at points

along the power distribution system and their integration within management tools.

Safety and electromagnetic compatibility (EMC) requirements are outside the scope of this document

and are covered by other standards and regulations. However, information given in this document can

be of assistance in meeting these standards and regulations.
Conformance of data centres to the present document is covered in Clause 4.

The use of the data centre stored energy or alternate sources to be used by the grid is not in the scope of

this document and is for consideration in future specifications.
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.

EN 13160 (all parts), Leak detection systems
IEC 60076-11, Power transformers — Part 11: Dry-type transformers
IEC 60364 (all parts), Low-voltage electrical installations
IEC 60947 (all parts), Low-voltage switchgear and controlgear

IEC 61000-2-4, Electromagnetic compatibility (EMC) — Part 2-4: Environment — Compatibility levels in

industrial plants for low-frequency conducted disturbances
IEC 61439 (all parts), Low-voltage switchgear and controlgear assemblies
© ISO/IEC 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/IEC 22237-3:2021(E)

IEC 61557-12, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. —

Equipment for testing, measuring or monitoring of protective measures — Part 12: Performance measuring

and monitoring devices (PMD)

IEC 61869-2:2012, Instrument transformers — Part 2: Additional requirements for current transformers

IEC 62040 (all parts), Uninterruptible power systems (UPS)

IEC 62053-21, Electricity metering equipment (a.c.) — Particular requirements — Part 21: Static meters

for active energy (classes 1 and 2)

IEC 62053-22, Electricity metering equipment (a.c.) — Particular requirements — Part 22: Static meters

for active energy (classes 0,2 S and 0,5 S)

IEC 62271-200, High-voltage switchgear and controlgear — Part 200. AC metal-enclosed switchgear and

controlgear for rated voltages above 1 kV and up to and including 52 kV
IEC 62305 (all parts), Protection against lightning

IEC 62586-1, Power quality measurement in power supply systems — Part 1: Power quality instruments

(PQI)

IEC 62586-2, Power quality measurement in power supply systems — Part 2: Functional tests and

uncertainty requirements

IEC 62974-1, Monitoring and measuring systems used for data collection, gathering and analysis — Part 1:

Device requirements

IEC 88528-11, Reciprocating internal combustion engine driven alternating current generating sets —

Part 11: Rotary uninterruptible power systems — Performance requirements and test methods

IEC/TS 62749, Assessment of power quality — Characteristics of electricity supplied by public networks

ISO/IEC 22237-1, Information technology — Data centre facilities and infrastructures — Part 1: General

concepts

ISO/IEC 22237-4, Information technology — Data centre facilities and infrastructures — Part 4:

Environmental control

ISO/IEC/TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:

Security systems

ISO/IEC 30129, Information technology — Telecommunications bonding networks for buildings and other

structures
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 22237-1 and the following

apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
© ISO/IEC 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/IEC 22237-3:2021(E)
3.1.1
active power

under periodic conditions, mean value, taken over one period, T, of the instantaneous power, p:

P = ∫ ptd

Note 1 to entry: Under sinusoidal conditions, the active power is the real part of the complex power S, thus

P = Re S.
Note 2 to entry: The coherent SI unit for active power is watt, W.
[SOURCE: IEC 60050-131:2002, 131-11-42]
3.1.2
additional supply

power supply that provides power in the event of failure of primary (3.1.22) and/or secondary supply

(3.1.24)
3.1.3
apparent power

product of the r.m.s. voltage U between the terminals of a two-terminal element or two-terminal circuit

and the r.m.s. electric current I in the element or circuit S = UI

Note 1 to entry: Under sinusoidal conditions, the apparent power is the modulus of the complex power S,

thus S = |S|.
Note 2 to entry: The coherent SI unit for apparent power is voltampere, VA.
[SOURCE: IEC 60050-131:2002, 131-11-41]
3.1.4
capacitive load

load that is capacitive, so that the alternating current is out of phase with and leads the voltage

3.1.5
catenary
wire hung at a specific tension between supporting structures of power cabling
3.1.6
diverse route

alternative separate pathway intended to provide adequate segregation from another pathway, in order

to maintain service provision in the event of physical damage to one of the pathways

3.1.7
dual-corded equipment
equipment served by multiple power supply input interfaces
3.1.8
emergency power off
EPO

designated device to provide emergency switching which disconnects power from one or more data

centre facilities, infrastructures or spaces

Note 1 to entry: The configuration and function of emergency power off devices can be subject to national or

local regulations.
3.1.9
fire compartment
discrete zone designed to contain a fire within that zone
© ISO/IEC 2021 – All rights reserved
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ISO/IEC 22237-3:2021(E)
3.1.10
high voltage
voltage whose nominal r.m.s. value is 35 kV < U ≤ 230 kV

Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can

be different.
3.1.11
inductive load

load that is inductive, so that the alternating current is out of phase with and lags behind the voltage

3.1.12
IT load

electrical consumption of all the information technology equipment, providing data storage, processing

and transport services, measured at its input terminals including all on-board integrated power

supplies and cooling fans
3.1.13
load factor

ratio, expressed as a numerical value or as a percentage, of the consumption within a specified period

(year, month, day, etc.), to the consumption that would result from continuous use of the maximum or

other specified demand occurring within the same period

Note 1 to entry: This term should not be used without specifying the demand and the period to which it relates.

Note 2 to entry: The load factor for a given demand is also equal to the ratio of the utilization time to the time in

hours within the same period.
[SOURCE: IEC 60050-691:1973, 691-10-02]
3.1.14
locally protected socket

sockets (3.1.26) which continue to deliver power to connected equipment for a defined period following

failure of power supply and distribution equipment by means of a battery supply or UPS adjacent to, or

co-located with, those sockets (e.g. emergency lighting)
3.1.15
low voltage
voltage whose nominal r.m.s. value is U ≤ 1 kV
3.1.16
Main-Tie-Tie-Main

electrical connection between two power supply or power distribution circuits which allows current

to flow in either direction and containing two circuit breakers enabling maintenance while one of the

circuits is active
3.1.17
medium voltage
voltage whose nominal r.m.s. value is 1 kV < U ≤ 35 kV

Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can

be different.
3.1.18
pathway
defined route for cables between termination points
[SOURCE: ISO/IEC 14763-2:2019, 3.1.34]
© ISO/IEC 2021 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/IEC 22237-3:2021(E)
3.1.19
power factor

under periodic conditions, ratio of the absolute value of the active power (3.1.1), P, to the apparent power

(3.1.3), S: λ = |P|/S

Note 1 to entry: This is the ratio of the active (real) power flowing to the load to the apparent power (as a result of

the capacitive or inductive nature of the load) and is a dimensionless number between 0 and 1.

[SOURCE: IEC 60050-131:2002, 131-11-46, modified — new Note 1 to entry add
...

FINAL
INTERNATIONAL ISO/IEC
DRAFT
STANDARD FDIS
22237-3
ISO/IEC JTC 1/SC 39
Information technology — Data centre
Secretariat: ANSI
facilities and infrastructures —
Voting begins on:
2021-07-05
Part 3:
Voting terminates on:
Power distribution
2021-08-30
Technologie de l’information — Installation et infrastructures de
centres de traitement de données —
Partie 3: Distribution de puissance
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/IEC FDIS 22237-3:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC FDIS 22237-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC FDIS 22237-3:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and abbreviated terms ................................................................................................................................ 2

3.1 Terms and definitions ....................................................................................................................................................................... 2

3.2 Abbreviated terms ............................................................................................................................................................................... 6

3.3 Symbols ......................................................................................................................................................................................................... 6

4 Conformance ............................................................................................................................................................................................................. 7

5 Power supply and distribution within data centres ........................................................................................................ 7

5.1 Functional elements ........................................................................................................................................................................... 7

5.1.1 General...................................................................................................................................................................................... 7

5.1.2 Power supply to the data centre ......................................................................................................................... 8

5.1.3 Power distribution within the data centre ................................................................................................ 9

5.2 Dimensioning of power distribution systems ...........................................................................................................10

6 Availability ...............................................................................................................................................................................................................11

6.1 General requirements ....................................................................................................................................................................11

6.2 Power supply .........................................................................................................................................................................................11

6.2.1 Capacity planning .........................................................................................................................................................11

6.2.2 Availability of the utility supply .......................................................................................................................13

6.2.3 Power quality ...................................................................................................................................................................14

6.2.4 Load presented to the utility supply ............................................................................................................15

6.2.5 Equipment ..........................................................................................................................................................................15

6.2.6 Availability Class design options .....................................................................................................................17

6.3 Power distribution ............................................................................................................................................................................23

6.3.1 Capacity planning .........................................................................................................................................................23

6.3.2 Power quality ...................................................................................................................................................................24

6.3.3 Equipment ..........................................................................................................................................................................25

6.3.4 Availability Class design options .....................................................................................................................25

6.4 Incorporation of low voltage direct current distribution ...............................................................................29

6.5 Additional considerations ..........................................................................................................................................................29

6.5.1 Residual current measurement ........................................................................................................................29

6.5.2 Lightning and surge protection ........................................................................................................................29

6.5.3 Segregation of power distribution cabling and information technology cabling .30

6.6 Emergency power off (EPO) .....................................................................................................................................................30

6.6.1 Requirements ..................................................................................................................................................................30

6.6.2 Recommendations .......................................................................................................................................................30

7 Physical security ................................................................................................................................................................................................30

7.1 General ........................................................................................................................................................................................................30

7.2 Access ...........................................................................................................................................................................................................30

7.2.1 Power supply ...................................................................... ..............................................................................................30

7.2.2 Power distribution ......................................................................................................................................................30

7.2.3 Attachment of unauthorized end-equipment ......................................................................................30

7.3 Internal environmental events ...............................................................................................................................................31

7.3.1 Power supply ...................................................................... ..............................................................................................31

7.3.2 Power distribution .....................................................................................................................................................31

7.4 External environmental events ..............................................................................................................................................31

8 Energy efficiency enablement and power distribution .............................................................................................31

8.1 General ........................................................................................................................................................................................................31

8.2 Granularity Level 1 ...........................................................................................................................................................................32

8.2.1 Requirements ..................................................................................................................................................................32

© ISO/IEC 2021 – All rights reserved iii
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ISO/IEC FDIS 22237-3:2021(E)

8.2.2 Recommendations .......................................................................................................................................................33

8.3 Granularity Level 2 ...........................................................................................................................................................................33

8.3.1 Requirements ..................................................................................................................................................................33

8.3.2 Recommendations .......................................................................................................................................................33

8.4 Granularity Level 3 ...........................................................................................................................................................................34

8.4.1 Requirements ..................................................................................................................................................................34

8.4.2 Recommendations .......................................................................................................................................................34

8.5 Cabling infrastructure to support energy efficiency enablement ............................................................34

Bibliography .............................................................................................................................................................................................................................35

iv © ISO/IEC 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC FDIS 22237-3:2021(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that are

members of ISO or IEC participate in the development of International Standards through technical

committees established by the respective organization to deal with particular fields of technical

activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international

organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the

work.

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 document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives or www .iec .ch/ members

_experts/ refdocs).

Attention is drawn to the possibility that some of the elements of this document may be the subject

of patent rights. ISO and IEC 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 (see www .iso .org/ patents) or the IEC

list of patent declarations received (see patents.iec.ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html. In the IEC, see www .iec .ch/ understanding -standards.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 39, Sustainability, IT & Data Centres.

This first edition cancels and replaces the first edition (ISO/IEC TS 22237-3:2018), which has been

technically revised.
The main changes compared to the previous edition are as follows:

— availability requirements have been aligned with ISO/IEC 22237-1 and ISO/IEC 22237-4;

— figures have been updated.

A list of all parts in the ISO/IEC 22237 series can be found on the ISO and IEC websites.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html and www .iec .ch/ national

-committees.
© ISO/IEC 2021 – All rights reserved v
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ISO/IEC FDIS 22237-3:2021(E)
Introduction

The unrestricted access to internet-based information demanded by the information society has led to

an exponential growth of both internet traffic and the volume of stored/retrieved data. Data centres

are housing and supporting the information technology and network telecommunications equipment

for data processing, data storage and data transport. They are required both by network operators

(delivering those services to customer premises) and by enterprises within those customer premises.

Data centres need to provide modular, scalable and flexible facilities and infrastructures to easily

accommodate the rapidly changing requirements of the market. In addition, energy consumption

of data centres has become critical, both from an environmental point of view (reduction of carbon

footprint), and with respect to economic considerations (cost of energy) for the data centre operator.

The implementation of data centres varies in terms of:
a) purpose (enterprise, co-location, co-hosting or network operator facilities);
b) security level;
c) physical size; and
d) accommodation (mobile, temporary and permanent constructions).
NOTE Cloud services can be provided by all data centre types mentioned.

The needs of data centres also vary in terms of availability of service, the provision of security and

the objectives for energy efficiency. These needs and objectives influence the design of data centres in

terms of building construction, power distribution, environmental control, telecommunications cabling

and physical security. Effective management and operational information are required to monitor

achievement of the defined needs and objectives.

The ISO/IEC 22237 series specifies requirements and recommendations to support the various parties

involved in the design, planning, procurement, integration, installation, operation and maintenance of

facilities and infrastructures within data centres. These parties include:

1) owners, operators, facility managers, ICT managers, project managers, main contractors;

2) consultants, architects, building designers and builders, system and installation designers, auditors

and commissioning agents;
3) suppliers of equipment; and
4) installers, maintainers.

At the time of publication of this document, the ISO/IEC 22237 series comprises the following

documents:

— ISO/IEC 22237-1, Information technology — Data centre facilities and infrastructures — Part 1:

General concepts;

— ISO/IEC TS 22237-2, Information technology — Data centre facilities and infrastructures — Part 2:

Building construction;

— ISO/IEC 22237-3 (this document), Information technology — Data centre facilities and infrastructures —

Part 3: Power distribution;

— ISO/IEC 22237-4, Information technology — Data centre facilities and infrastructures — Part 4:

Environmental control;

— ISO/IEC TS 22237-5, Information technology — Data centre facilities and infrastructures — Part 5:

Telecommunications cabling infrastructure;
vi © ISO/IEC 2021 – All rights reserved
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ISO/IEC FDIS 22237-3:2021(E)

— ISO/IEC TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:

Security systems;

— ISO/IEC TS 22237-7: Information technology — Data centre facilities and infrastructures — Part 7:

Management and operational information.

The inter-relationship of the specifications within the ISO/IEC 22237 series is shown in Figure 1.

Figure 1 — Schematic relationship between the ISO/IEC 22237 series of documents

ISO/IEC TS 22237-2 to ISO/IEC TS 22237-6 specify requirements and recommendations for particular

facilities and infrastructures to support the relevant classification for “availability”, “physical security”

and “energy efficiency enablement” selected from ISO/IEC 22237-1.

This document, ISO/IEC 22237-3, addresses facilities and infrastructures for power supplies to, and

power distribution within, data centres together with the interfaces for monitoring the performance of

those facilities and infrastructures in line with ISO/IEC 22237-7 (in accordance with the requirements

of ISO/IEC 22237-1). The line diagrams used in certain figures are not intended to replace the more

familiar electrical circuit diagrams associated with power supply and distribution systems, which are

included where relevant.

ISO/IEC TS 22237-7 addresses operational and management information (in accordance with the

requirements of ISO/IEC 22237-1).

This document is intended for use by and collaboration between architects, building designers and

builders, and system and installation designers.

The ISO/IEC 22237 series does not address the selection of information technology and network

telecommunications equipment, software and associated configuration issues.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/IEC FDIS 22237-3:2021(E)
Information technology — Data centre facilities and
infrastructures —
Part 3:
Power distribution
1 Scope

This document addresses power supplies to, and power distribution within, data centres based upon

the criteria and classifications for “availability”, “physical security” and “energy efficiency enablement”

within ISO/IEC 22237-1.
This document specifies requirements and recommendations for the following:
a) power supplies to data centres;
b) power distribution systems to all equipment within data centres;
c) telecommunications infrastructure bonding;
d) lightning protection;

e) devices for the measurement of the power consumption and power quality characteristics at points

along the power distribution system and their integration within management tools.

Safety and electromagnetic compatibility (EMC) requirements are outside the scope of this document

and are covered by other standards and regulations. However, information given in this document can

be of assistance in meeting these standards and regulations.
Conformance of data centres to the present document is covered in Clause 4.

The use of the data centre stored energy or alternate sources to be used by the grid is not in the scope of

this document and is for consideration in future specifications.
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.

EN 13160 (all parts), Leak detection systems
IEC 60076-11, Power transformers — Part 11: Dry-type transformers
IEC 60364 (all parts), Low-voltage electrical installations
IEC 60947 (all parts), Low-voltage switchgear and controlgear

IEC 61000-2-4, Electromagnetic compatibility (EMC) — Part 2-4: Environment — Compatibility levels in

industrial plants for low-frequency conducted disturbances
IEC 61439 (all parts), Low-voltage switchgear and controlgear assemblies
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ISO/IEC FDIS 22237-3:2021(E)

IEC 61557-12, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. —

Equipment for testing, measuring or monitoring of protective measures — Part 12: Performance measuring

and monitoring devices (PMD)

IEC 61869-2:2012, Instrument transformers — Part 2: Additional requirements for current transformers

IEC 62040 (all parts), Uninterruptible power systems (UPS)

IEC 62053-21, Electricity metering equipment (a.c.) — Particular requirements — Part 21: Static meters

for active energy (classes 1 and 2)

IEC 62053-22, Electricity metering equipment (a.c.) — Particular requirements — Part 22: Static meters

for active energy (classes 0,2 S and 0,5 S)

IEC 62271-200, High-voltage switchgear and controlgear — Part 200. AC metal-enclosed switchgear and

controlgear for rated voltages above 1 kV and up to and including 52 kV
IEC 62305 (all parts), Protection against lightning

IEC 62586-1, Power quality measurement in power supply systems — Part 1: Power quality instruments

(PQI)

IEC 62586-2, Power quality measurement in power supply systems — Part 2: Functional tests and

uncertainty requirements

IEC 62974-1, Monitoring and measuring systems used for data collection, gathering and analysis — Part 1:

Device requirements

IEC 88528-11, Reciprocating internal combustion engine driven alternating current generating sets —

Part 11: Rotary uninterruptible power systems — Performance requirements and test methods

IEC/TS 62749, Assessment of power quality — Characteristics of electricity supplied by public networks

ISO/IEC 22237-1, Information technology — Data centre facilities and infrastructures — Part 1: General

concepts

ISO/IEC 22237-4:— , Information technology — Data centre facilities and infrastructures — Part 4:

Environmental control

ISO/IEC/TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:

Security systems

ISO/IEC 30129, Information technology — Telecommunications bonding networks for buildings and other

structures
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 22237-1 and the following

apply.

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/

1) Under preparation. Stage at the time of publication: ISO/IEC FDIS 22237-4:2021.

2 © ISO/IEC 2021 – All rights reserved
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ISO/IEC FDIS 22237-3:2021(E)
3.1.1
active power

under periodic conditions, mean value, taken over one period, T, of the instantaneous power, p:

P = ∫ ptd

Note 1 to entry: Under sinusoidal conditions, the active power is the real part of the complex power S, thus

P = Re S.
Note 2 to entry: The coherent SI unit for active power is watt, W.
[SOURCE: IEC 60050-131:2002, 131-11-42]
3.1.2
additional supply

power supply that provides power in the event of failure of primary (3.1.22) and/or secondary supply

(3.1.24)
3.1.3
apparent power

product of the r.m.s. voltage U between the terminals of a two-terminal element or two-terminal circuit

and the r.m.s. electric current I in the element or circuit S = UI

Note 1 to entry: Under sinusoidal conditions, the apparent power is the modulus of the complex power S,

thus S = |S|.
Note 2 to entry: The coherent SI unit for apparent power is voltampere, VA.
[SOURCE: IEC 60050-131:2002, 131-11-41]
3.1.4
capacitive load

load that is capacitive, so that the alternating current is out of phase with and leads the voltage

3.1.5
catenary
wire hung at a specific tension between supporting structures of power cabling
3.1.6
diverse route

alternative separate pathway intended to provide adequate segregation from another pathway, in order

to maintain service provision in the event of physical damage to one of the pathways

3.1.7
dual-corded equipment
equipment served by multiple power supply input interfaces
3.1.8
emergency power off
EPO

designated device to provide emergency switching which disconnects power from one or more data

centre facilities, infrastructures or spaces

Note 1 to entry: The configuration and function of emergency power off devices can be subject to national or

local regulations.
3.1.9
fire compartment
discrete zone designed to contain a fire within that zone
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ISO/IEC FDIS 22237-3:2021(E)
3.1.10
high voltage
voltage whose nominal r.m.s. value is 35 kV < U ≤ 230 kV

Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can

be different.
3.1.11
inductive load

load that is inductive, so that the alternating current is out of phase with and lags behind the voltage

3.1.12
IT load

electrical consumption of all the information technology equipment, providing data storage, processing

and transport services, measured at its input terminals including all on-board integrated power

supplies and cooling fans
3.1.13
load factor

ratio, expressed as a numerical value or as a percentage, of the consumption within a specified period

(year, month, day, etc.), to the consumption that would result from continuous use of the maximum or

other specified demand occurring within the same period

Note 1 to entry: This term should not be used without specifying the demand and the period to which it relates.

Note 2 to entry: The load factor for a given demand is also equal to the ratio of the utilization time to the time in

hours within the same period.
[SOURCE: IEC 60050-691:1973, 691-10-02]
3.1.14
locally protected socket

sockets (3.1.26) which continue to deliver power to connected equipment for a defined period following

failure of power supply and distribution equipment by means of a battery supply or UPS adjacent to, or

co-located with, those sockets (e.g. emergency lighting)
3.1.15
low voltage
voltage whose nominal r.m.s. value is U ≤ 1 kV
3.1.16
Main-Tie-Tie-Main

electrical connection between two power supply or power distribution circuits which allows current

to flow in either direction and containing two circuit breakers enabling maintenance while one of the

circuits is active
3.1.17
medium voltage
voltage whose nominal r.m.s. value is 1 kV < U ≤ 35 kV

Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can

be different.
3.1.18
pathway
defined route for cables between termination points
[SOURCE: ISO/IEC 14763-2:2019, 3.1.34
...

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