ISO/IEC TS 22237-3:2018

TECHNICAL ISO/IEC TS
SPECIFICATION 22237-3
First edition
2018-05
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 TS 22237-3:2018(E)
©
ISO/IEC 2018

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ISO/IEC TS 22237-3:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO/IEC TS 22237-3:2018(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 . 5
4 Conformance . 6
5 Power supply and distribution within data centres . 6
5.1 General . 6
5.2 Dimensioning of power distribution systems . 8
6 Availability . 9
6.1 General requirements . 9
6.2 Power supply . 9
6.2.1 Capacity planning . 9
6.2.2 Availability of the utility supply .11
6.2.3 Power quality .12
6.2.4 Load presented to the utility supply .12
6.2.5 Equipment .13
6.2.6 Availability Class design options .14
6.3 Power distribution .17
6.3.1 Capacity planning .17
6.3.2 Power quality .19
6.3.3 Equipment .19
6.3.4 Availability Class design options .20
6.4 Incorporation of LVDC distribution .22
6.5 Additional considerations .22
6.5.1 Lightning and surge protection .22
6.5.2 Segregation of power distribution cabling and information technology cabling .22
6.6 Emergency power off .22
6.6.1 Requirements .22
6.6.2 Recommendations .22
7 Physical security .22
7.1 General .22
7.2 Access .22
7.2.1 Power supply . .22
7.2.2 Power distribution .23
7.2.3 Attachment of unauthorised end-equipment .23
7.2.4 Cabling infrastructure to support access control .23
7.3 Internal environmental events .23
7.3.1 Power supply . .23
7.3.2 Power distribution .23
7.4 External environmental events .23
8 Energy efficiency enablement and power distribution .23
8.1 General .23
8.2 Granularity Level 1 .24
8.2.1 Requirements .24
8.2.2 Recommendations .24
8.3 Granularity Level 2 .25
8.3.1 Requirements .25
8.3.2 Recommendations .25
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ISO/IEC TS 22237-3:2018(E)

8.4 Granularity Level 3 .25
8.4.1 Requirements .25
8.4.2 Recommendations .25
8.5 Cabling infrastructure to support energy efficiency enablement .25
Annex A (informative) Example implementations of power distribution .26
Bibliography .29
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ISO/IEC TS 22237-3:2018(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. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
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).
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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 39, Sustainability for and by Information Technology.
A list of all parts in the ISO/IEC TS 22237 series can be found on the ISO website.
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ISO/IEC TS 22237-3:2018(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 economical 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;
d) accommodation (mobile, temporary and permanent constructions).
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 and physical security.
Effective management and operational information is required to monitor achievement of the defined
needs and objectives.
The ISO/IEC TS 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, facility managers, ICT managers, project managers, main contractors;
2) consultants, architects, building designers and builders, system and installation designers;
3) facility and infrastructure integrators, suppliers of equipment;
4) installers, maintainers.
At the time of publication of this document, the ISO/IEC TS 22237 series will comprise the following
documents:
— ISO/IEC TS 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 TS 22237-3, Information technology — Data centre facilities and infrastructures — Part 3:
Power distribution;
— ISO/IEC TS 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 TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:
Security systems;
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ISO/IEC TS 22237-3:2018(E)

— 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 TS 22237 series is shown in Figure 1.
Figure 1 — Schematic relationship between the ISO/IEC TS 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 TS 22237-1.
This document, 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 TS 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 the operational and management information (in accordance with the
requirements of ISO/IEC TS 22237-1).
This document is intended for use by and collaboration between architects, building designers and
builders, system and installation designers.
The ISO/IEC TS 22237 series does not address the selection of information technology and network
telecommunications equipment, software and associated configuration issues.
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TECHNICAL SPECIFICATION ISO/IEC TS 22237-3:2018(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 TS 22237-1.
This document specifies requirements and recommendations for the following:
a) power supplies to data centres;
b) power distribution systems within data centres;
c) facilities for both normal and emergency lighting;
d) equipotential bonding and earthing;
e) lightning protection;
f) devices for the measurement of the power consumption 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 may
be of assistance in meeting these standards and regulations.
Conformance of data centres to the present document is covered in Clause 4.
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.
ISO/IEC TS 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 TS 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 TS 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:
Security systems
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ISO/IEC TS 22237-3:2018(E)

ISO/IEC 30129, Information technology — Telecommunications bonding networks for buildings and other
structures
IEC 60044-1:1996, Instrument transformers — Part 1: Current transformers
IEC 60947 (all parts), Low-voltage switchgear and controlgear
IEC 61000-2-4:2002, 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
IEC 62040 (all parts), Uninterruptible power systems (UPS)
IEC 62305 (all parts), Protection against lightning
IEC 62305-4, Protection against lightning — Part 4: Electrical and electronic systems within structures
IEC 88528-11, Reciprocating internal combustion engine driven alternating current generating sets —
Part 11: Rotary uninterruptible power systems — Performance requirements and test methods
EN 50160, Voltage characteristics of electricity supplied by public electricity networks
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 TS 22237-1 and the
following 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 https: //www .iso .org/obp
3.1.1
active power
real power
product of r.m.s. voltage, r.m.s. current and power factor
Note 1 to entry: Expressed as W.
3.1.2
additional supply
backup supply
power supply that provides power in the event of failure of primary and/or secondary supply
3.1.3
apparent power
product of r.m.s. voltage and r.m.s current
Note 1 to entry: Expressed as VA.
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
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ISO/IEC TS 22237-3:2018(E)

3.1.6
diverse route
alternative, separate, pathway intended to provide adequate segregation from another pathway, in
order to provide resilient service provision in the event of physical damage to one of the pathways
3.1.7
emergency power off
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.
3.1.8
fire compartment
discrete zone designed to contain a fire within that zone
3.1.9
high voltage
voltage whose nominal r.m.s. value is 36 kV < U ≤ 150 kV
n
Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can
be different.
[SOURCE: EN 50160:2010, 3.7]
3.1.10
inductive load
load that is inductive, so that the alternating current is out of phase with and lags behind the voltage
3.1.11
information technology equipment
equipment providing data storage, processing and transport services together with equipment
dedicated to providing direct connection to core and/or access networks
3.1.12
IT load
electrical consumption of all the information technology equipment measured at its input terminals
including all on-board integrated power supplies and cooling fans
3.1.13
load factor
ratio of the average load to the peak load over a period of time
3.1.14
locally protected supply provision
sockets 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
n
[SOURCE: EN 50160:2010, 3.9]
3.1.16
mechanical cooling load
electrical consumption of all the plant and components used to provide environmental control within
the data centre, generally comprising compressors, controls, fans, pumps and humidifiers
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ISO/IEC TS 22237-3:2018(E)

3.1.17
medium voltage
voltage whose nominal r.m.s. value is 1 kV < U ≤ 36 kV
n
Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can
be different.
[SOURCE: EN 50160:2010, 3.11]
3.1.18
pathway
defined route for cables between termination points
[SOURCE: ISO/IEC 14763-2:2012, 3.1.43]
3.1.19
power factor
under periodic conditions, ratio of the absolute value of the active power P to the apparent power
S: λ = |P|/S
Note 1 to entry: 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]
3.1.20
protected supply provision
no break protected supply provision
sockets which continue to deliver power to connected equipment for a defined period following failure
of power supply and distribution equipment
3.1.21
primary distribution equipment
equipment which is required to manage, control and convert incoming power supplies (primary,
secondary and, where appropriate, additional) in a form suitable for distribution by secondary
distribution equipment
3.1.22
primary supply
principal power supply that provides power to the data centre under normal operating conditions
3.1.23
resistive load
load in which the alternating current is in phase with the voltage
Note 1 to entry: The total reactance is zero.
3.1.24
secondary distribution equipment
equipment which is required to manage, control and distribute the power provided by the primary
distribution equipment to the short-break and unprotected sockets within the data centre and to the
tertiary distribution equipment
Note 1 to entry: The power supply may be single-phase AC, three-phase AC or DC. If there is a change from 3-phase
to 1-phase supply, this is generally achieved at the secondary distribution equipment that is served directly from
the primary distribution equipment.
3.1.25
secondary supply
power supply that provides power to the data centre in conjunction with the primary supply under
normal operating conditions
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ISO/IEC TS 22237-3:2018(E)

3.1.26
short-break supply provision
back-up supported supply provision
sockets which, upon failure of power supply and distribution equipment, will be provided with power
from an additional power supply after a defined period
3.1.27
socket
connection enabling supply of power to attached equipment
Note 1 to entry: This may be a de-mateable or a hardwired connection.
3.1.28
tertiary distribution equipment
power supply equipment, typically accommodated within the cabinets, frames and racks of the data
centre spaces, which directly feeds the protected sockets therein
3.1.29
total harmonic current distortion
measurement of the harmonic distortion present on a current level, defined as the ratio of the sum of
the powers of all harmonic components to the power of the fundamental frequency
3.1.30
total harmonic voltage distortion
measurement of the harmonic distortion present on a voltage level, defined as the ratio of the sum of
the powers of all harmonic components to the power of the fundamental frequency
3.1.31
unprotected supply provision
sockets which fail to deliver power to connected equipment following failure in power supply and
distribution equipment
3.2 Abbreviated terms
For the purposes of this document, the abbreviated terms given in ISO/IEC TS 22237-1 and the
following apply.
AC Alternating Current
DC, dc Direct Current
EPO Emergency Power Off
HV High Voltage
ITE Information technology equipment
LV Low Voltage
MV Medium Voltage
r.m.s. root mean square
SPD Surge Protective Device
THCD Total Harmonic Current Distortion
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ISO/IEC TS 22237-3:2018(E)

THVD Total Harmonic Voltage Distortion
TVSS Transient Voltage Surge Suppression
UPS Uninterruptible Power Supply
4 Conformance
For a data centre to conform to this document:
a) it shall feature a power supply and distribution design solution that meets the required Availability
Class of Cla
...