ISO/IEC 22237-1:2021

INTERNATIONAL ISO/IEC
STANDARD 22237-1
First edition
2021-10
Information technology — Data centre
facilities and infrastructures —
Part 1:
General concepts
Technologie de l’information — Installation et infrastructures de
centres de traitement de données —
Partie 1: Concepts généraux
Reference number
© ISO/IEC 2021
© ISO/IEC 2021
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Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 5
4 Conformance . 6
5 Business risk analysis . 6
5.1 General . 6
5.2 Business impact analysis. 7
5.3 Risk analysis . 7
6 Data centre design overview . 9
6.1 General . 9
6.2 Spaces and facilities . 9
7 Classification system for the design of data centre facilities and infrastructures .12
7.1 General .12
7.2 Availability . 12
7.2.1 General .12
7.2.2 Single-site data centres .12
7.2.3 Multi-site data centres . 14
7.3 Physical security .15
7.3.1 General .15
7.3.2 Protection against unauthorized access . 15
7.3.3 Protection against intrusion. 15
7.3.4 Protection against environmental events . 15
7.4 Energy efficiency enablement . 16
7.4.1 General . 16
7.4.2 Power distribution system . 17
7.4.3 Environmental monitoring and control. 17
7.4.4 Operational processes and KPIs . 17
8 Design and implementation process .17
8.1 Introduction . 17
8.2 Design phases . 18
8.2.1 Phase 1 — Strategy . 18
8.2.2 Phase 2 — Objectives . 18
8.2.3 Phase 3 — System specifications . 19
8.2.4 Phase 4 — Design proposal . 19
8.2.5 Phase 5 — Decision . 19
8.2.6 Phase 6 — Functional design . 20
8.2.7 Phase 7 — Approval . 20
8.2.8 Phase 8 — Final design and project plan. 20
8.2.9 Phase 9 — Contract . 20
8.2.10 Phase 10 — Construction . 20
8.2.11 Phase 11 — Operation .20
9 Design principles .20
9.1 Design reference documentation . 20
9.2 Design principles to support energy efficiency . 21
9.3 Design principles for electromagnetic interference . 21
9.4 Design principles to support operational excellence . 21
9.5 Design principles for availability, reliability and resilience. 21
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Annex A (informative) Availability and Reliability .23
Annex B (informative) Availability description .28
Bibliography .29
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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 22237-1:2018), which has been
technically revised.
The main changes are as follows:
— reference to Key Performance Indicators of ISO/IEC 30134 series has been included;
— Clause 7 (Availability) has been revised;
— the design processes (Clause 8) and design principles (Clause 9) have been moved from an annex to
the main body of the document;
— the existing Annex A has been removed;
— new Annexes A and B have been added.
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.
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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/installation designers, auditors,
test 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 (this document), 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, 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;
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— 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
This document, ISO/IEC 22237-1, defines the general concepts for the design and operation of data
centres. This includes a business risk and operational cost analysis as well as a classification system for
data centres with respect to “availability”, “physical security” and “energy efficiency enablement”.
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 TS 22237-7 addresses the operational and management information (in accordance with the
requirements of this document).
This document is intended for use by and collaboration between architects, building designers and
builders, 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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INTERNATIONAL STANDARD ISO/IEC 22237-1:2021(E)
Information technology — Data centre facilities and
infrastructures —
Part 1:
General concepts
1 Scope
This document:
a) describes the general principles for data centres upon which the requirements of the ISO/IEC 22237
series are based;
b) defines the common aspects of data centres including terminology, parameters and reference
models (functional elements and their accommodation) addressing both the size and complexity of
their intended purpose;
c) describes general aspects of the facilities and infrastructures required to support data centres;
d) specifies a classification system, based upon the key criteria of “availability”, “security” and
“energy-efficiency” over the planned lifetime of the data centre, for the provision of effective
facilities and infrastructure;
e) details the issues to be addressed in a business risk and operating cost analysis enabling application
of the classification of the data centre;
f) provides a reference to the operation and management of data centres.
The following topics are outside of the scope of the ISO/IEC 22237 series:
1) the selection of information technology and network telecommunications equipment, software and
associated configuration issues are outside the scope of this International Standard;
2) quantitative analysis of overall service availability resulting from multi-site data centres;
3) safety and electromagnetic compatibility (EMC) requirements (covered by other standards and
regulations. However, information given in this document can be of assistance in meeting these
standards and regulations).
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 22237-6, Information technology — Data centre facilities and infrastructures — Part 6:
Security systems
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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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/
3.1.1
availability
ability to be in a state to perform as required
[SOURCE: IEC 60050-192:2015, 192-01-23, modified — Note 1 to entry and Note 2 to entry deleted.]
3.1.2
building entrance facility
facility (3.1.16) that provides all necessary services, and which complies with all relevant regulations
for the entry of specific infrastructures (3.1.21) or services into a building
3.1.3
building security
facilities (3.1.16) and systems (3.1.30) necessary to provide the required levels of security at the
entrance to and within the building containing the data centre (3.1.8)
3.1.4
co-hosting data centre
data centre (3.1.8) in which multiple customers are provided with access to network(s), servers and
storage equipment on which they operate their own services/applications
Note 1 to entry: Both the information technology equipment and the support infrastructure (3.1.21) of the
building are provided as a service by the data centre operator.
3.1.5
co-location data centre
data centre (3.1.8) in which multiple customers locate their own network(s), servers and storage
equipment
Note 1 to entry: The support infrastructure (3.1.21) of the building (such as power distribution and environmental
control) is provided as a service by the data centre operator.
3.1.6
computer room space
area within the data centre (3.1.8) that accommodates the data processing, data storage and
telecommunication equipment (3.1.33) that provides the primary function of the data centre
3.1.7
control room space
area within the data centre (3.1.8) used to control the operation of the data centre and to act as a central
point for all control and monitoring functions
3.1.8
data centre
a structure, or group of structures, dedicated to the centralized accommodation, interconnection
and operation of information technology and network telecommunications (3.1.31) equipment
providing data storage, processing and transport services together with all the facilities (3.1.16) and
infrastructures (3.1.21) for power distribution and environmental control together with the necessary
levels of resilience and security required to provide the desired service availability (3.1.1)
Note 1 to entry: A structure can consist of multiple buildings and/or spaces with specific functions to support the
primary function.
Note 2 to entry: The boundaries of the structure or space considered the data centre, which includes the
information and communication technology equipment and supporting environmental controls, can be defined
within a larger structure or building.
© ISO/IEC 2021 – All rights reserved

[SOURCE: ISO/IEC 30134-1:2016, 3.1.4]
3.1.9
data centre security
necessary facilities (3.1.16) and systems (3.1.30) that provide the required levels of security at the
entrance to and within the data centre (3.1.8)
3.1.10
demarcation point
point where the operational control or ownership changes
3.1.11
electrical distribution space
area used for housing facilities to distribute electrical power between the transformer space (3.1.36) and
electrical spaces (3.1.12) within the data centre (3.1.8) or elsewhere within the premises or individual
buildings within the premises
3.1.12
electrical space
area within the data centre (3.1.8) used for housing facilities (3.1.16) to deliver and control electrical
power to the data centre spaces (including switchboards, batteries, uninterruptible power systems
(3.1.37) (UPS), etc.)
3.1.13
enterprise data centre
data centre (3.1.8) that is operated by an enterprise which has the sole purpose of the delivery and
management of services to its employees and customers
3.1.14
external premises security
facilities (3.1.16) and systems (3.1.30) that provide the required levels of security for the area between
the building and the boundary of the premises
3.1.15
energy efficiency enablement
ability to measure the energy consumption and to allow calculation and reporting of energy efficiency
of the various facilities (3.1.16) and infrastructures (3.1.21)
3.1.16
facility
spaces and pathways that accommodate a specific infrastructure (3.1.21)
3.1.17
functional capability
ability of the data centre (3.1.8) (or system (3.1.30) or sub-system) to deliver its intended function
3.1.18
functional element
source of supply, device or path
3.1.19
generator space
area used for housing the installation of electrical power supply generation equipment together with
control systems (3.1.30), storage of associated fuels or energy conversion equipment
3.1.20
holding space
area within the data centre (3.1.8) used for the holding of equipment prior to being brought into service
or having been taken out of service
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3.1.21
infrastructure
technical systems (3.1.30) providing functional capability (3.1.17) of the data centre (3.1.8)
Note 1 to entry: Examples are power distribution, environmental control and physical security (3.1.25).
3.1.22
main distributor
distributor used to make connections between the main distribution cabling subsystem, network
access cabling subsystem and cabling subsystems and active equipment
[SOURCE: ISO/IEC 11801-5:2017, 3.1.11, modified — removed “as specified in ISO/IEC 11801-1”.]
3.1.23
mechanical space
area that is used for housing mechanical equipment and infrastructure (3.1.21) that provides
environmental control for the data centre (3.1.8) spaces (including chillers and water treatment, air
handling and fire suppression systems [3.1.30])
3.1.24
network operator data centre
data centre (3.1.8) that has the primary purpose of the delivery and management of broadband services
to the operator's customers
3.1.25
physical security
measures (combining physical and technological controls), procedures and responsibilities to maintain
the desired level of availability (3.1.1) for the facilities (3.1.16) and infrastructures (3.1.21) of the data
centres (3.1.8) in relation to access control and environmental events
3.1.26
planned downtime
period of time during which a system (3.1.30) or sub-system does not provide functional capability
(3.1.17) whilst it undergoes maintenance or is switched off to test the response of a related system or
sub-system
3.1.27
premises entrance facility
facility (3.1.16) that provides all necessary services, and which complies with all relevant regulations,
for the entry of specific infrastructures (3.1.21) or services into premises
3.1.28
reliability
ability to perform as required, without failure, for a given time interval, under given conditions
[SOURCE: IEC 60050-192:2015, 192-01-24, modified — Note 1 to entry to Note 3 to entry deleted.]
3.1.29
storage space
secured area where general goods and/or data centre (3.1.8) goods to be used in the premises and data
centre are stored
3.1.30
system
set of interrelated functional elements (3.1.18) considered in a defined context as a whole and separated
from their environment
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3.1.31
telecommunications
branch of technology concerned with the transmission, emission, and reception of signs, signals, writing,
images, and sounds, that is, information of any nature by cable, radio, optical, or other electromagnetic
systems (3.1.30)
[SOURCE: ISO/IEC 11801-1:2017, 3.1.51, modified.]
3.1.32
telecommunications cabling
infrastructure (3.1.21) from the telecommunications space(s) (3.1.34) to the premises entrance facility
(3.1.27)
3.1.33
telecommunication equipment
equipment within the data centre (3.1.8) that provides telecommunication services within the data
centre
3.1.34
telecommunications space
area which may house demarcation points (3.1.10) and telecommunication equipment (3.1.33) associated
with the building entrance facility (3.1.2) and which may allow service providers restricted access to the
data centre (3.1.8)
3.1.35
testing space
area within the data centre (3.1.8) used for the testing and configuring of equipment prior to being
brought into service
Note 1 to entry: Testing space is sometimes called staging area.
3.1.36
transformer space
area used for housing equipment necessary to convert voltage levels and/or provide necessary isolation
for the connection to the equipment within the premises or individual buildings within the premises
3.1.37
uninterruptible power system
combination of convertors, switches and energy storage devices (such as batteries), constituting a
power system (3.1.30) for maintaining continuity of load power in case of input power failure
Note 1 to entry: Continuity of load power occurs when voltage and frequency are within rated steady-state and
transient tolerance bands and with distortion and interruptions within the limits specified for the output port.
Input power failure occurs when voltage and frequency are outside rated steady-state and transient tolerance
bands or with distortion or interruptions outside the limits specified for the UPS.
[SOURCE: IEC 62040-1:2017, 3.101]
3.1.38
unplanned downtime
unexpected time taken, following a failure of functional capability (3.1.17), to repair the relevant
infrastructure (3.1.21) together with the “re-boot” time necessary to recover functional capability
following that repair
3.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
CRAC computer room air conditioner/conditioning
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CRAH computer room air handling unit
MDT mean downtime
MTBF mean time between failures
MTTR mean time to repair
NOC network operating centre
UPS uninterruptible power system
4 Conformance
For a data centre design to conform to this document:
a) a business risk analysis according to Clause 5 shall be completed;
b) an appropriate Availability Class in 7.2 shall be selected using a business risk analysis in accordance
with Clause 5;
c) appropriate Protection Classes for the data centre spaces and pathways shall be in accordance with
7.3.1;
d) an appropriate energy efficiency enablement level in 7.4 shall be selected;
e) the design process of Clause 8 (or equivalent) shall be applied;
f) the design principles of Clause 9 shall be applied.
NOTE The application of the design process in Clause 8 is not mandatory for an assessment of existing data
centres.
5 Business risk analysis
5.1 General
The overall availability of a data centre is a measure of the continuity of its data processing, storage,
and transport functions. The acceptable level of the overall availability of a data centre is determined
by a number of factors, including:
a) a business impact analysis (see 5.2): the cost associated with a failure of service provision, which
depends upon a number of factors including the function and importance of the data centre;
b) externally applied commercial pressures (e.g. insurance costs).
There is a link between the availability of the infrastructures specified in the ISO/IEC 22237 series
and the overall availability, but it should be recognized that the recovery of intended data processing,
storage, and transport functionality following the repair of an infrastructure failure depends on many
factors related to the configuration of the hardware and software providing that functionality.
As a result, the role of the infrastructure is to support overall availability objectives but this is not the
sole factor in their attainment.
The availability of each of the facilities and infrastructures of the data centre required to support the
desired overall availability is described by an availability classification (see 7.2). The design of each of
the data centre infrastructures shall take account of their impact on overall availability and the costs
associated with the predicted downtime associated with failure or planned downtime for maintenance.
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The design and physical security of the facilities and infrastructures of the data centre shall be
subjected to a risk analysis (see 5.3) which maps identified risk events against the requirements of the
availability classification (see 7.2). The availability classification for each infrastructure is described
as providing low, medium, high and very high availability. Clause 7 further describes the situations
(risk events) for which each infrastructure is protected against failure. Other approaches are to apply
“% availability” to infrastructures but this is not supported by the ISO/IEC 22237 series for reasons
explained in Annex A.
A business risk analysis identifies the aspects of the facilities and infrastructures that require
investment in terms of design improvements to reduce their impact and/or probability of those risk
events.
5.2 Business impact analysis
This document does not define methods of analysis for the cost of downtime. Standards such as
IEC 31010, ISO/TS 22317 or ISO 22301 provide useful guidance.
The parameters to be considered within such an analysis will depend upon the purpose of the data
centre. Some organizations can assign a monetary value (or range) to loss of service which may include
the following:
a) immediate financial penalties;
b) consequential losses;
c) an assessment of longer-term damage to business reputation e.g. an internet service provider or a
financial institution.
Although cost is often considered when analysing downtime, other impacts should also be considered.
Data centres containing life safety, legal, medical and criminal information can have individually
recognized consequences from unplanned downtime.
5.3 Risk analysis
This document does not define methods of risk analysis. Standards such as ISO 31000 and IEC 31010
provide useful guidance on this topic.
Risk analysis may be used as a management tool allowing the comparison with the acceptable total
risk and showing trends resulting from mitigation activity. For the purposes of this document, the risk
associated with an event concerning the facilities and infrastructures of the data centre which disrupts
the provision of service of the data centre is defined as event risk which is a function of impact and
probability where:
a) impact is the magnitude or severity of adverse incidents or impacts, expressed numerically or
nominally expected duration of loss of service (availability) of the event;
b) probability is the likelihood of the event.
The impact of risk may be assessed using different units of measure e.g. cost, safety, etc.
The total risk to the functional capability of the data centre is a function of the event risks associated
with each facility and infrastructure provided that those risks are quantified on the same basis. If
related to the output of the business impact analysis (see 5.2) the financial value of the total risk can be
estimated.
The risks considered should include external threats which can affect the facilities and infrastructures
including in particular the location, which could be geographical (air traffic, flooding etc.), political
(wars, trouble spots, terror, etc.) or affecting neighbourhood relations (if, for example, fire hazards exist
due to filling stations, chemical storage, etc.) and thus influence the likelihood of a potential downtime.
In addition, potential risks resulting from internal and external attacks by the staff or others should be
part of the overall risk evaluation.
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Impact can be categorized as:
1) low: Loss of non-critical services;
2) medium: Failure of critical system functional elements but no loss of redundancy;
3) high: Loss of critical system redundancy but no loss of service;
4) critical: Loss of critical service or loss of life (which may be extended to address personal injury).
The probability of an event occurring can be defined in a similar way, that is:
1) very low;
2) low;
3) medium;
4) high.
Each risk can be quantified on a risk map as shown in Figure 2. High risk events inhabit the top right-
hand corner of the figure and low risk events inhabit the bottom left hand corner.
Key
X probability of an event
Y impact
Figure 2 — Example of risk map
Having identified the risk of the possible events associated with data centre facilities and
infrastructures, the downtime cost with that event shall be determined to enable design decisions to be
made that reduce the risk (by means of reducing the impact or probability of the event).
© ISO/IEC 2021 – All rights reserved

6 Data centre design overview
6.1 General
Data centres differ in terms of their purpose e.g. co-hosting data centre, co-location data centre,
enterprise data centre, network operator data centre. Data centres can also differ significantly with
respect to their physical size, ranging from:
a) a data centre in a building housing a small quantity of storage and server equipment to provide
information technology services to the occupants of that building; to
b) a data centre housing a large quantity of such equipment providing information technology services
via diverse internal and external telecommunications networks and requiring sophisticated power
distribution and environmental control facilities housed in one or more buildings dedicated to
ensuring the operation of the data centre.
This clause provides a general design overview for data centres independent of their purpose and their
size.
6.2 Spaces and facilities
Figure 3 shows a schematic representation of the spaces required by a large data centre within a
building and within premises containing one or more buildings.
The data centre may share certain spaces with the rest of the building including:
a) building entrance facilities;
b) personnel entrance(s);
c) docking/loading bay(s);
d) generators space(s) including fuel storage;
e) transformer space(s);
f) electrical distribution space(s);
g) telecommunications spaces(s).
The need for the above spaces and facilities within the building depends upon the purpose of both the
building and the data centre. Any sharing of these spaces and facilities will depend not only on the size
but also on the defined Availability and Protection Classes of the data centre and the functions of the
remainder of the building. For example, in buildings housing large data centres, the facilities and spaces
supporting the data centre can be dedicated to the data centre with separate spaces being provided for
the remainder of the building.
The area within the building designated as a data centre can contain the following spaces:
1) personnel entrance(s);
2) main distributor space(s);
3) computer room space(s) and associated testing space(s);
4) electrical space(s);
5) mechanical space(s) (which accommodate(s) e.g. CRAC and CRAH);
6) control room space(s) (which accommodate(s) the NOC);
7) office space(s);
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8) storage space(s) and holding space(s).
The spaces and facilities also address building security, data centre security and external premises
security.
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Figure 3 — Typical schematic diagram of premises containing a data centre
© ISO/IEC 2021 – All rights reserved

Within the area of the building designated as a data centre, the need for, and contents of, the spaces
depends upon the purpose of the data centre, its anticipated power consumption and the need for
environmental control.
The need for segregation of spaces depends on availability and fire protection considerations,
requirements for security and upon the need for environmental control.
As examples, a small enterprise data centre can comprise a single room having the function of a
computer room space and an electrical space without physical segregation whereas a large data centre
can require one or more segregated spaces of each type identified in Figure 3.
Functional spaces can be accommodated in one or more physical spaces and in one or more buildings
and premises and subject to multiple ownership.
7 Classification system for the design of data centre facilities and infrastructures
7.1 General
For the purposes of the ISO/IEC 22237 series, data centres facilities and infrastructures are designated
with respect to:
a) Availability Classes (see 7.2);
b) Protection Classes (see 7.3);
c) Energy efficiency enablement levels (see 7.4).
These designations are used in combination to determine the relevant requirements and
recommendations for the following facilities and infrastructures:
1) building construction (see ISO/IEC TS 22237-2);
2) power distribution (see ISO/IEC 22237-3);
3) environmental control (see ISO/IEC 22237-4);
4) telecommunications cabling infrastructure (see ISO/IEC TS 22237-5);
5) security systems (see ISO/IEC TS 22237-6).
7.2 Availability
7.2.1 General
Data centres can be single-site or configured to operate across multiple sites.
7.2.2 describes the availability concepts and requirements for a single-site data centre.
7.2.3 describes the use of a multi-site data centre to improve the overall service availability.
Annex B summarizes the availability classification specified in this document.
7.2.2 Single-site data centres
The required availability of the facilities and infrastructures that support the functionality of the data
centre is of the utmost significance. The data centre owner/user shall determine the desired availability
of the overall set of facilities and infrastructures using business risk analysis and business impact
analysis (Clause 5). It is recognized that availability requirements can vary with time of day, week or
month.
© ISO/IEC 2021 – All rights reserved

The ISO/IEC 22237 series defines four Classes of availability. Based on the outcome of the business risk
analysis in Clause 5 an Availability Class shall be selected for the following infrastructures:
— power supply and distribution;
— environmental control;
— telecommunications cabling.
The availability of the entire data centre depends on the Availability Classes of its infrastructures.
The selection of the Availability Class shall be made based on the following design objectives (for
requirements and recommendations specific to each infrastructure see the appropriate part of the ISO/
IEC 22237 series).
For the set of facilities and infrastructures of a data centre to be considered to be of a given Availability
Class,
...