IEC TS 62966-3:2021

IEC TS 62966-3 ®
Edition 1.0 2021-01
TECHNICAL
SPECIFICATION
colour
inside
Mechanical structures for electrical and electronic equipment – Aisle
containment for it cabinets –
Part 3: Aspects of operational and personal safety
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IEC TS 62966-3 ®
Edition 1.0 2021-01
TECHNICAL
SPECIFICATION
colour
inside
Mechanical structures for electrical and electronic equipment – Aisle

containment for it cabinets –
Part 3: Aspects of operational and personal safety

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.240 ISBN 978-2-8322-9318-8

– 2 – IEC TS 62966-3:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 7
3 Terms and definitions . 7
4 Safety requirements of an aisle containment. 8
4.1 General safety requirements . 8
4.2 Escape routes, emergency exits, escape doors, escape and evacuation plan . 8
4.2.1 Recommended dimensions of escape routes and escape
doors/emergency exits . 8
4.2.2 Functional aspects of escape doors . 11
4.2.3 Lighting and signposting of escape routes . 11
4.2.4 Escape and evacuation plan . 12
4.3 General – Fire protection in an aisle containment . 12
4.3.1 Overview . 12
4.3.2 Fire prevention . 13
4.3.3 Fire and smoke detection . 13
4.3.4 Fire fighting device . 16
4.3.5 Arrangement of extinguishing nozzles . 17
4.4 Lighting conditions . 19
Bibliography . 20

Figure 1 – Minimum width of escape routes in an aisle containment . 10
Figure 2 – Minimum height of escape routes in an aisle containment . 10
Figure 3 – Typical arrangement of an aisle containment representing a walk-in-
equipment solution . 13
Figure 4 – Cold and hot aisle containment (showing air flow and temperature areas) . 14
Figure 5 – Arrangement of aspirating smoke detectors (ASDs) in a cold aisle
containment with or without raised floor . 15
Figure 6 – Arrangement of aspirating smoke detectors (ASDs) in a hot aisle
containment . 16
Figure 7 – Arrangement of extinguishing nozzles in a cold aisle containment with or
without raised floor (showing flow-direction of extinguishing gas) . 18

Table 1 – Minimum width of escape routes and maximum reduction of clearance . 9

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MECHANICAL STRUCTURES FOR ELECTRICAL
AND ELECTRONIC EQUIPMENT –
AISLE CONTAINMENT FOR IT CABINETS –

Part 3: Aspects of operational and personal safety

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In
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• the required support cannot be obtained for the publication of an International Standard,
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Technical Specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.

– 4 – IEC TS 62966-3:2021 © IEC 2021
IEC TS 62966-3, which is a Technical Specification, has been prepared by subcommittee
48D: Mechanical structures for electrical and electronic equipment, of IEC technical
committee 48: Electrical connectors and mechanical structures for electrical and electronic
equipment.
The text of this Technical Specification is based on the following documents:
DTS Report on voting
48D/725/DTS 48D/731/RVDTS
Full information on the voting for the approval of this Technical Specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62966 series, published under the general title Mechanical
structures for electrical and electronic equipment – Aisle containment for IT cabinets, can be
found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
INTRODUCTION
This Part 3 of IEC 62966 serves as a guide for a consideration from a safety viewpoint of the
dimensional and air conditioning aspects of cold and hot aisle containments in data centres
described in IEC 62966-1 and IEC 62966-2.
Where aspects of this Technical specification conflict with national regulations and laws of the
member states concerned, the provisions of these national regulations shall apply.
Consideration is given to safety-related aspects, such as:
a) escape and evacuation plans;
b) escape routes;
c) emergency exits;
d) functional aspects of escape doors;
e) lighting conditions;
f) lighting and signposting of escape routes;
g) fire protection;
taking into account the existing stringent requirements placed on the protection of IT
equipment and the availability of the data the equipment contains.

– 6 – IEC TS 62966-3:2021 © IEC 2021
MECHANICAL STRUCTURES FOR ELECTRICAL
AND ELECTRONIC EQUIPMENT –
AISLE CONTAINMENT FOR IT CABINETS –

Part 3: Aspects of operational and personal safety

1 Scope
This part of IEC 62966 defines the requirements for operational and personal safety of aisle
containments for IT cabinets.
The aim is to provide physical security for the IT equipment installed in the containment using
the criteria “availability” and “safety”.
The requirements apply to all operational, working and maintenance procedures.
This document does not apply to ordinary persons, when using installations and equipment.
The requirements described herein are also intended to ensure that it is possible for
authorized personnel to enter and remain in the containment (as accessible equipment) and
to maintain or upgrade the systems installed in the containment without risk. It should also be
possible to evacuate the containment quickly and safely at any time, especially in the event of
a fire or any other hazardous situation, whilst reducing the health risk to personnel to a
minimum.
Aspects relating to computing, data processing, data storage, building protection or the data
centre itself do not fall within the scope of this document. Only those additional aspects
arising from the integration of an aisle containment are considered.
The design and positioning of an aisle containment, which is integrated in the data centre, has
influence on the following different aspects of operational safety:
a) escape and evacuation plans;
b) escape routes;
c) emergency exits;
d) functional aspects of escape doors;
e) lighting conditions
f) lighting and signposting of escape routes;
g) fire protection.
In this document, these operational safety requirements and recommendations are
considered.
To achieve the highest effectiveness, all these requirements are considered as much as
possible during the design of an aisle containment.
This document applies to normal operations, not to the initial installation of the containment.

2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
http://www.electropedia.org/
• IEC Electropedia: available at
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
escape route
intended route to a place of safety
3.2
emergency exit
exit which is part of an escape route and leads directly to the outside or to a safe area
3.3
escape and evacuation plan
straightforward and comprehensible document that provides information relating to escape
routes and fire fighting equipment
3.4
escape door
every door in an escape route is an escape door
3.5
hold time
time during which a concentration of fire extinguishant shall be maintained at an effective
level within the space being protected. The predicted hold time shall be determined by the
door fan test or a full discharge test.
3.6
extinguishing gas
electrically non-conducting gaseous extinguishing agent, that, upon evaporation, does not
leave a residue
3.7
fire detector
part of a fire alarm system containing at least one sensor that continually or at intervals
monitors at least one appropriate physical and/or chemical characteristic (fire characteristic)
that occurs in the event of a fire, and that also transmits at least one corresponding signal to
the control and indicating equipment

– 8 – IEC TS 62966-3:2021 © IEC 2021
3.8
lead time
time between the alarm signal and the release of the extinguishing medium
3.9
aspirating smoke detector
ASD
high-sensitivity detector, which consists of a central detection unit, that draws air through a
system of pipes to detect smoke
Note 1 to entry: The sampling chamber is based on a nephelometer, that detects the presence of smoke particles
suspended in air by detecting the light scatterd by them in the chamber. In most cases aspirating smoke detectors
require a fan unit to draw in a sample of air from the monitored area through its system of pipes.
3.10
delay device
device that is part of a fire-fighting installation designed to ensure that flooding does not take
place until the fire alarm devices have been activated and the specified lead time has expired
3.11
extinguishing gas concentration
value for the concentration of extinguishing gas present in the atmosphere of the area being
flooded expressed as % vol
3.12
qualified person
defined as a person who, by possession of a recognized degree, certificate, or
professional standing, or who by extensive knowledge, training and experience, has
successfully demonstrated his/her ability to solve or resolve problems relating to the
subject matter, the work, or the project
3.13
hazard area
containment area plus any adjacent areas that will be flooded with the extinguishing gas
4 Safety requirements of an aisle containment
4.1 General safety requirements
The mechanical design of an aisle containment, consisting of cabinets, cover panels, doors
and roof panels shall have adequate design considerations to prevent hazards to people.
The mechanical parts of the aisle containment shall be free of sharp edges, burrs, etc., that
could present a safety hazard to personnel involved in their assembly, installation, use or
maintenance.
The aisle containment roof panels cannot be walked on, therefore their design and
appearance shall make this obvious to personnel working in the data centre.
4.2 Escape routes, emergency exits, escape doors, escape and evacuation plan
4.2.1 Recommended dimensions of escape routes and escape doors/emergency exits
A cold or hot aisle containment that in an emergency represents the only escape route should
be dimensioned so that any personnel within it when a particular hazard occurs (e.g. a fire)
are able to evacuate it as rapidly as possible. It shall not be permitted to obstruct or lock the
escape routes.
The recommended minimum width of an escape route is determined by the maximum number
of personnel using the escape route in an emergency. This is shown in Table 1.
Table 1 – Minimum width of escape routes and maximum reduction of clearance
Number of persons Recommended minimum width of Maximum reduction of clearance
escape routes
(in aisle containment) (in the area of doors)
mm mm
up to 5 875 75
up to 20 1 000 150
The minimum width of the escape route shall not be constricted by fixed structures or
equipment or by the opening of doors in the escape direction. A reduction of the minimum
width of corridors by a maximum of 75 mm or 150 mm in the area of doors is not significant in
this case (see Figure 1).
However, the clearance in the area of doors shall at no point be less than 800 mm.
The clearance in the area of doors shall at no point be less than 850 mm if there are normally
up to 20 people in the hazard area.
National regulations and safety directives that deviate from these d
...