EN 50600-2-3:2014

Information technology - Data centre facilities and infrastructures - Part 2-3: Environmental control

This European Standard addresses environmental control within data centres based upon the criteria and classifications for “availability”, “security” and “energy efficiency enablement” within EN 50600 1. This European Standard specifies requirements and recommendations for the following: a) temperature control, b) fluid movement control, c) relative humidity control, d) particulate control, e) vibration, f) floor layout and equipment locations, g) energy saving practices, h) physical security of environmental control systems. For issues related to electromagnetic environment, see prEN 50600 2 5.

Informationstechnik - Einrichtungen und Infrastrukturen von Rechenzentren - Teil 2-3: Regelung der Umgebungsbedingungen

Technologie de l'information - Installation et infrastructures des centres de traitement de données - Partie 2-3: Contrôle environnemental

La présente Norme Européenne aborde les aspects liés au contrôle environnemental dans les centres de traitement de données, selon les critères et classifications de “disponibilité”, “sécurité” et “validation d'efficacité énergétique » définis dans EN 50600-1. La présente Norme Européenne spécifie les exigences et les recommandations pour ce qui suit: a) contrôle des températures b) contrôle des mouvements de fluides c) contrôle de l’humidité d) contrôle des particules e) vibrations f) schéma d’implantation au sol et localisation des équipements g) pratiques pour économiser l’énergie h) sécurité physique des systèmes de contrôle environnemental Pour les problèmes relatifs à l'environnement électromagnétique, voir l'EN 50600-2-5.

Informacijska tehnologija - Naprave in infrastruktura podatkovnega centra - 2-3. del: Nadzor okolja

Standard obravnava nadzor okolja v podatkovnih centrih na podlagi meril in klasifikacij za »dostopnost«, »varnost« in »omogočanje energetske učinkovitosti« v okviru standarda EN 50600-1. Ta evropski standard določa zahteve in priporočila za naslednje elemente: a) nadzor temperature, b) nadzor pretoka tekočin, c) nadzor relativne vlažnosti, d) nadzor delcev, e) vibracije, f) tloris in lokacije opreme, g) prakse, ki prispevajo k varčevanju z energijo, h) fizično varnost sistemov za nadzor okolja. Če vas zanimajo vprašanja, povezana z elektromagnetnim okoljem, si oglejte standard EN 50600-2-5.

General Information

• Status: Withdrawn
• Publication Date: 09-Oct-2014
• Withdrawal Date: 31-Aug-2017
• ICS: 35.020 - Information technology (IT) in general
• ICS: 35.110 - Networking
• ICS: 35.160 - Microprocessor systems
• Technical Committee: CLC/TC 215 - Electrotechnical aspects of telecommunication equipment
• Drafting Committee: CLC/TC 215 - Electrotechnical aspects of telecommunication equipment
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 29-Apr-2022
• Completion Date: 29-Apr-2022
• Mandate: M/462 - Standardisation mandate addressed to CEN, CENELEC and ETSI in the field of ICT to enable efficient energy use in fixed and mobile information and communication networks
• Ref Project: SIST EN 50600-2-3:2014 - Information technology - Data centre facilities and infrastructures -- Part 2-3: Environmental control

Relations

• Replaced By: EN 50600-2-3:2019 - Information technology - Data centre facilities and infrastructures - Part 2-3: Environmental control
• Effective Date: 06-Jun-2017

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2014
Informacijska tehnologija - Naprave in infrastruktura podatkovnega centra - 2-3.
del: Nadzor okolja
Information technology - Data centre facilities and infrastructures -- Part 2-3:
Environmental control
Informationstechnik - Einrichtungen und Infrastrukturen von Rechenzentren -- Teil 2-3:
Überwachung der Umgebung
Technologie de l'information - Installation et infrastructures des centres de traitement de
données -- Partie 2-3: Contrôle environnemental
Ta slovenski standard je istoveten z: EN 50600-2-3:2014
ICS:
13.020.99 Drugi standardi v zvezi z Other standards related to
varstvom okolja environmental protection
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50600-2-3

NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 35.020; 35.110; 35.160
English Version
Information technology - Data centre facilities and infrastructures
- Part 2-3: Environmental control
Technologie de l'information - Installation et infrastructures Informationstechnik - Einrichtungen und Infrastrukturen von
des centres de traitement de données - Partie 2-3: Contrôle Rechenzentren - Teil 2-3: Überwachung der Umgebung
environnemental
This European Standard was approved by CENELEC on 2014-09-01. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50600-2-3:2014 E
Contents Page
Foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references. 7
3 Terms, definitions and abbreviations . 7
3.1 Terms and definitions . 7
3.2 Abbreviations . 9
4 Conformance . 9
5 Environmental control within data centres . 9
5.1 General . 9
5.2 Environmental control of data centre spaces . 10
6 Availability . 14
6.1 General . 14
6.2 Design options by space . 14
6.3 Environmental control system capacity planning with respect to expansion . 18
6.4 Environmental control system capacity planning with respect to resilience . 18
7 Physical security . 18
7.1 General . 18
7.2 Access . 18
8 Energy efficiency enablement . 18
8.1 General . 18
8.2 Measurement of temperature . 19
8.3 Measurement of relative humidity . 20
8.4 Measurement of air pressure . 21
8.5 Coolant flow rates . 21
8.6 Heat removal . 21
8.7 Outside air. 22
8.8 Provision of alarms . 22
8.9 Measurement requirements by Granularity Level. 22
Annex A (normative) Distribution methodologies for temperature-controlled air in computer
room space . 23
A.1 Cabinet or rack air flow management . 23
A.2 Access floor air flow management . 23
A.3 Hot aisles/cold aisles . 24
Annex B (informative) Control system concepts . 26
B.1 General . 26
B.2 Control of exhaust temperature (return air) . 26
B.3 Control of supply temperature (supply air) . 26

– 3 – EN 50600-2-3:2014
B.4 Combination of control of supply and exhaust temperature . 26
B.5 Supply air relative humidity . 26
B.6 Proportion of outside air . 26
Bibliography . 27

Foreword
This document (EN 50600-2-3:2014) has been prepared by CLC/TC 215 “Electrotechnical aspects of
telecommunication equipment”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2015-09-01
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2017-09-01
conflicting with this document have to
be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and
the European Free Trade Association.

– 5 – EN 50600-2-3:2014
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.
This series of European Standards 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) 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 European Standard, the EN 50600 series will comprise the following
standards:
— EN 50600-1, Information technology — Data centre facilities and infrastructures — Part 1: General
concepts;
— EN 50600-2-1, Information technology — Data centre facilities and infrastructures — Part 2-1: Building
construction;
— EN 50600-2-2, Information technology — Data centre facilities and infrastructures — Part 2-2: Power
distribution;
— EN 50600-2-3, Information technology — Data centre facilities and infrastructures — Part 2-3:
Environmental control;
— EN 50600-2-4, Information technology — Data centre facilities and infrastructures — Part 2-4:
Telecommunications cabling infrastructure;
— EN 50600-2-5, Information technology — Data centre facilities and infrastructures — Part 2-5: Security
systems;
— EN 50600-2-6, Information technology — Data centre facilities and infrastructures — Part 2-6:
Management and operational information.
The inter-relationship of the standards within the EN 50600 series is shown in Figure 1.

Figure 1 — Schematic relationship between the EN 50600 standards
EN 50600-2-X standards specify requirements and recommendations for particular facilities and
infrastructures to support the relevant classification for “availability”, “physical security” and “energy efficiency
enablement” selected from EN 50600-1.
This European Standard addresses the environmental control facilities and infrastructure within data centres
together with the interfaces for monitoring the performance of those facilities and infrastructures in line with
EN 50600-2-6 (in accordance with the requirements of EN 50600-1).
This series of European Standards does not address the selection of information technology and network
telecommunications equipment, software and associated configuration issues.

– 7 – EN 50600-2-3:2014
1 Scope
This European Standard addresses environmental control within data centres based upon the criteria and
classifications for “availability”, “security” and “energy efficiency enablement” within EN 50600-1.
This European Standard specifies requirements and recommendations for the following:
a) temperature control,
b) fluid movement control,
c) relative humidity control,
d) particulate control,
e) vibration,
f) floor layout and equipment locations,
g) energy saving practices,
h) physical security of environmental control systems.
For issues related to electromagnetic environment, see EN 50600-2-5.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 50600-1, Information technology — Data centre facilities and infrastructures — Part 1: General concepts
1)
EN 50600-2-5 , Information technology — Data centre facilities and infrastructures — Part 2-5: Security
systems
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions in EN 50600-1 and the following apply.
3.1.1
adiabatic cooling
adiabatic cooling is a cooling system that is using the evaporative cooling principle to reduce the air
temperature
3.1.2
absolute humidity
quantity of water vapour in a given volume of air, expressed by mass
———————
1) Circulated for CENELEC enquiry.

3.1.3
access floor
system consisting of completely removable and interchangeable floor panels that are supported on
adjustable pedestals connected by stringers to allow the area beneath the floor to be used by building
services
Note 1 to entry: Also known as raised floor.
[SOURCE: EN 50600-2-1:2014, 3.1.1]
3.1.4
comfort environmental controls
controls which produce an environment which is appropriate for the effective performance of personnel in a
given space
3.1.5
dew point
temperature at which the water vapour in a gas begins to deposit as a liquid or ice, under standardized
conditions
[SOURCE: IEC 60050-212:2010, 212-18-11]
3.1.6
exhaust air temperature
the temperature of the air leaving the data centre building or the temperature of the air leaving the heat load
3.1.7
fresh air cooling
cooling system that uses the external air to cool the data centre either directly or indirectly
3.1.8
heat load
thermal power that is produced
3.1.9
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
3.1.10
outdoor air temperature
temperature of the air measured outside of the data centre building
3.1.11
relative humidity
ratio, expressed as a percentage, of the vapour pressure of water vapour in moist air to the saturation vapour
pressure with respect to water or ice at the same temperature
[SOURCE: IEC 60050-705:1995, 705-05-09]
3.1.12
return air temperature
temperature of the air re-entering the environmental control system e.g. the air handling unit
3.1.13
supply air temperature
temperature of the air entering the IT equipment

– 9 – EN 50600-2-3:2014
3.1.14
ventilation
supply of air motion in a space by circulation or by moving air through the space
Note 1 to entry: Ventilation can be produced by any combination of natural or mechanical supply and exhaust.
Note 2 to entry: Such systems may include partial treatment such as heating, relative humidity control, filtering or
purification, and, in some cases, evaporative cooling.
3.2 Abbreviations
For the purposes of this document, the abbreviations given in EN 50600-1 and the following apply.
UPS Uninterruptible Power Supply
CRAC Computer Room Air Conditioning (Unit)
IT Information Technology
ITE Information Technology Equipment
4 Conformance
For a data centre to conform to this European Standard:
a) it shall feature an environmental control solution that meets the requirements of Clauses 4 and 5;
b) it shall feature an approach to physical security in relation to the environmental control solution that
meets the requirements of Clause 6;
c) it shall feature an energy efficiency enablement solution that meets the requirements of the relevant
Granularity Level of Clause 7;
d) local regulations, including safety, shall be met.
5 Environmental control within data centres
5.1 General
5.1.1 Functional Elements
The environmental control system is one of the most important parts of the data centre infrastructure.
Excessive variations of temperature or relative humidity can directly affect the functional capability of the
data centre and its infrastructures.
The functional elements of the environmental control system are divided into primary and secondary
elements.
Primary elements relate to the mechanical generation of temperature controlled fluids. Secondary elements
relate to the distribution of fluids generated by the primary elements. See Table 1 for examples of these
elements.
Some environmental systems combine the function of primary and secondary elements.

Table 1 — Examples of Primary and Secondary Functional Elements
Area Fluid Functional Element(s)
Primary Water Water supply grid, chiller, pump(s)
Air Outside air intake, filter, heat exchanger
Secondary Water Pump(s), valve(s), pipe system, liquid cooled enclosures
Air Duct system, computer room air conditioning unit
It should be noted that a Class 1 environmental control system does not necessarily contain any of these
elements.
5.1.2 Requirements
The approach taken for the design of the environmental control system shall take into account available
technology, physical security and data centre availability.
The design of the environmental control system and the selection and installation of functional elements shall
take into consideration the effect of vibration on the data centre spaces.
The design of the environmental control system and the selection and installation of functional elements shall
take into consideration the effect of friction and/or obstruction in the pathways for temperature controlled
fluids. Operational controls shall be provided to ensure no degradation of fluid flow due to changes in the
pathways.
During the design phase the requirement for the number of air changes per unit time and air pressure shall
be established.
In all data centre spaces the requirements for filtration shall be considered.
In all spaces where there is a risk of damage to static-sensitive equipment from electro-static discharge the
relative humidity shall be maintained in accordance with the instructions of the supplier of the equipment to
be accommodated. Where no information exists or where the equipment manufacturer is not specified, a
minimum dew point of 5,5 °C shall be maintained.
Where direct fresh air cooling solutions are chosen the requirements analysis and the resulting methodology
of monitoring and control is of prime importance. In these circumstances particular consideration shall be
given to the control of contaminants.
For guidance on the ventilation requirements of activated gaseous suppression systems see EN 50600-2-5.
5.1.3 Recommendations
Opportunities for reductions in energy consumption exist where wider tolerances of temperature and relative
humidity can be tolerated in defined data centre spaces. It is recommended to use cooling units with
integrated vibration decoupling for all rotating parts (e.g. fan, compressor) or low vibration parts. If the
cooling units or other external components with rotating parts are not equipped with integrated vibration
decoupling the whole unit should be decoupled.
5.2 Environmental control of data centre spaces
5.2.1 Building entrance facilities
No specific requirements.
– 11 – EN 50600-2-3:2014
5.2.2 Personnel entrance(s)
Comfort environmental controls shall be applied to this space.
5.2.3 Docking/loading bay(s)
No specific requirements.
5.2.4 Generator space(s) including fuel storage
5.2.4.1 Generator spaces
Temperature shall be maintained in accordance with the instructions of the supplier of the equipment to be
accommodated. Where no information exists or where the equipment manufacturer is not specified the
temperature shall be maintained above 0 °C and should be above 10 °C.
Adequate ventilation shall be provided for combustion and for radiator cooling.
Where the manufacturer is not known at the time of design the maximum temperature shall be 35 °C.
Anti-condensation heating shall be provided for alternators and switchgear.
Temperature and the presence of particulates (smoke, carbon monoxide and fuel) shall be monitored. See
EN 50600-2-5 for further information regarding monitoring of smoke.
Heater elements in the generator engine may provide sufficient heat for this space, where this is not possible
thermostatically controlled heaters shall be applied.
5.2.4.2 Fuel storage systems
The fuel storage system shall be protected against continuous sub-zero ambient temperatures to avoid fuel
solidification.
The fuel storage systems shall be monitored for leakage.
NOTE The availability of generators can be adversely affected by cold (<10 °C) or poor quality fuel and can be
improved through the installation of crankcase heaters.
5.2.5 Transformer space(s)
Temperature shall be maintained in accordance with the instructions of the supplier of the equipment to be
accommodated unless the system has been de-rated for operation at higher ambient temperatures. Where
no information exists or where the equipment manufacturer is not specified the temperature shall be
maintained above 0 °C and should be above 10 °C.
The maximum ambient temperature shall not exceed the maximum temperature specified by the equipment
manufacturer unless the system has been de-rated for operation at higher ambient temperatures. Where the
manufacturer is not known at the time of design the maximum temperature shall be 35 °C.
Filtration against dust shall be provided, if required, in accordance with the instructions of the supplier of the
equipment to be accommodated.
Forced air cooling of the transformer should be considered at the design phase where this would represent
an improvement in transformer efficiency.
Anti-condensation heating shall be provided for switchgear.

Temperature and the presence of smoke particulates shall be monitored. See EN 50600-2-5 for further
information regarding monitoring of smoke.
5.2.6 Electrical distribution space(s)
Temperature shall be maintained in accordance with the instructions of the supplier of the equipment to be
accommodated. Where no information exists or where the equipment manufacturer is not specified the
temperature shall be maintained above 0 °C and should be above 10 °C.
Natural ventilation shall be provided.
The maximum ambient temperature shall not exceed the maximum temperature specified by the supplier of
the equipment to be accommodated unless the system has been de-rated for operation at higher ambient
temperatures. Where the manufacturer is not known at the time of design the maximum temperature shall be
40 °C.
Anti-condensation heating shall be provided.
Temperature controlled air extraction shall be provided, where the facility’s redundancy so requires
ventilation shall be by redundant fans each rated to the maximum load expected. Temperature and relative
humidity shall be monitored.
5.2.7 Telecommunication spaces(s)
Temperature and relative humidity shall be maintained in accordance with the instructions of the supplier of
the equipment to be accommodated. Where this is not known in advance temperature shall be maintained
between 10 °C and 30 °C with relative humidity maintained between 20 % and 70 %.
Temperature and relative humidity shall be monitored.
Where the data centre is supported by a single telecommunications space, or by multiple, non-resilient
telecommunications spaces, the space(s) shall have a single path resilient environmental control system (for
examples see 6.2.5.3).
5.2.8 Main Distributor spaces(s)
If external to computer room space the requirements of 5.2.7 shall be applied; if contained within the
computer room space then the requirements of 5.2.9 shall be applied.
5.2.9 Computer room space(s) and associated testing space(s)
The computer room space is the most important space from an environmental control perspective.
An analysis examining the balance between tight environmental controls versus high performance energy
saving controls with reference to the type of IT equipment to be accommodated shall be performed by the
owner of the data centre. The results of this analysis shall be compared with the business model for the data
centre.
Environmental controls shall be applied that maintain the following parameters within limits defined by the
requirements of the analysis described above:
a) operating temperature;
b) relative humidity;
c) air quality:
– 13 – EN 50600-2-3:2014
1) particulate content;
2) bacterial content;
3) gaseous contaminants.
The designer of the environmental control system shall assess the impact of the failure of the system on the
data centre infrastructure.
5.2.10 Electrical space(s)
See 5.2.15, if the electrical space contains UPS equipment.
Temperature shall be maintained in accordance with the instructions of the supplier of the equipment to be
accommodated. Where no information exists or where the equipment manufacturer is not specified the
temperature shall be maintained above 0 °C and should be above 10 °C.
Natural ventilation shall be provided.
The maximum ambient temperature shall not exceed the maximum temperature specified by the supplier of
the equipment to be accommodated unless the system has been de-rated for operation at higher ambient
temperatures. Where the manufacturer is not known at the time of design the maximum temperature shall be
40 °C.
Anti-condensation heating shall be provided.
Temperature and relative humidity shall be monitored.
5.2.11 Mechanical space(s)
Temperature and relative humidity shall be monitored.
If the mechanical space accommodates electrical equipment then the requirements of 5.2.10 apply.
5.2.12 Control room space(s)
Comfort environmental controls shall be applied to this space.
5.2.13 Office space(s)
Comfort environmental controls shall be applied to this space.
5.2.14 Storage and holding space(s)
Basic environmental controls shall be applied (temperature and relative humidity); temperature and relative
humidity shall be monitored.
5.2.15 Accommodation of UPS equipment
5.2.15.1 Static and Rotary UPS
Temperature shall be maintained in accordance with the instructions of the supplier of the equipment to be
accommodated. Where no information exists or where the UPS equipment is not specified the temperature
shall be maintained between 15 °C and 35 °C (non-condensing); where storage batteries are included in the
UPS space the requirements of 5.2.15.3 shall be applied.

Air conditioning, rated for the maximum heat output of the UPS system, shall be provided if the external
ambient conditions preclude the use of filtered fresh air.
Closed loop monitoring for temperature and relative humidity shall be provided.
Waste heat should be used to pre-heat standby generator plant of the UPS system where possible.
5.2.15.2 Diesel rotary UPS
The environmental controls required for the accommodation of diesel rotary UPS are as stated in 5.2.4.
5.2.15.3 Batteries
Where UPS storage batteries are located away from the UPS equipment that they serve, temperature shall
be controlled in accordance with the manufacturer’s instructions. Where no information exists or where the
UPS equipment is not specified the temperature shall be maintained at (20 ± 2) °C.
Ventilation shall be provided to avoid hydrogen accumulation. Where mechanical extraction is used the fans
shall be redundant and fed from separate secondary power supply points.
It is recommended that Hydrogen monitoring is provided.
See EN 50272-2 for further information.
6 Availability
6.1 General
The environmental control system shall be designed to support the Availability Class chosen following the
risk assessment undertaken in accordance with the availability classification defined EN 50600-1.
This standard defines four Classes of Environmental Control Systems of increasing availability (Class 2,
Class 3, Class 4 and Enhanced Class 4).
6.2 Design options by space
6.2.1 General
All systems in data centres utilize the concept of ‘N’ when planning the load and the redundancy, e.g. N, N+1,
2N or 2(N+1), etc. where N is seldom equal to 1. To maximize the utilization of capital plant, and so minimize
energy standing losses, the designer shall take into account the increased redundancy for running at partial
load when choosing how to specify the configuration of ‘N’.
Four design options, of increasing availability are specified:
It should be noted that Class 1 as defined by EN 50600-1 has no meaning within this standard and no
specific requirements exist.
a) Class 2: Single path (no resilience) - a single path system without resilience is suitable where it is
acceptable that a single fault in an element in the path will result in loss of functional capability and
where maintenance requires the load to be shut-down.
b) Class 3: Single path (resilience provided by redundancy of components) - a single path system with
resilience is suitable where it is required that a single fault in the path will not result in loss of
functional capability because sufficient redundant components in each sub-assembly are included
and where routine planned maintenance does not require the load to be shut-down. Major faults may

– 15 – EN 50600-2-3:2014
result in unplanned load shutdown and some maintenance routines may require planned load
shutdown.
c) Class 4: Multi-path resilience and concurrent repair/operate solution - an active/passive multi-path
system with resilience is suitable where it is required that a single fault in the path will not result in
loss of functional capability because sufficient redundant components in each sub-assembly are
included and where routine planned maintenance does not require the load to be shut-down. Major
faults may result in unplanned load shutdown but maintenance routines will not require planned load
shutdown. The passive path serves to act as the concurrent maintenance enabler as well as
reducing to the minimum the recovery of service time (minimising the mean downtime) after a major
fault. The designer should aim to have the least number of common-points-of-failure possible
between the active and passive paths, including segregated routing and physical
compartmentalisation.
d) Enhanced Class 4: Multi-path resilience, concurrent repair/operate, and fault tolerant solution - an
active/active multi-path system is suitable where it is required that no single fault in any path will
result in loss of functional capability and where planned maintenance does not require the load to be
shut-down. A major fault in one path will not result in unplanned load shutdown and no maintenance
routines will require planned load shutdown by use of the other active path. Each path serves to act
as the concurrent maintenance enabler as well as avoiding any recovery of service time (mean
downtime of zero) after a major fault. The designer should aim to have no common-point-of-failure
between the two paths, including segregated routing, physical compartmentalisation and fire-rated
enclosures. Each path does not require N+1 redundancy unless the client specifies that during
maintenance or repair (planned or unplanned) where one path is removed from service the
remaining path has to retain a higher degree of resilience than N. This is most valid when each path
is modular and contains more than three elements. It is assumed in this standard that during system
maintenance or repair, unless specified by the client, a degraded level of resilience is permitted.
6.2.2 Spaces excluded from the availability classification
The following spaces are not subject to a classification for the design of environmental control systems in
relation to availability:
a) building entrances facilities,
b) personnel entrances,
c) docking/loading bays,
d) generator space (s),
e) transformer space,
f) electrical distribution space(s),
g) telecommunications space(s),
h) electrical space(s),
i) mechanical space(s),
j) control room space(s),
k) office space(s),
l) storage and holding space(s).

6.2.3 Main Distributor space(s)
If external to computer room space there are no scalable design options for this space. If contained within
the Computer Room space the requirements of 6.2.4 shall be applied.
6.2.4 Computer room space(s) and associated testing space(s)
6.2.4.1 General
The computer room space is the most important space from an environmental control perspective.
6.2.4.2 Class 2: Single path (no resilience)
An example of a chilled water cooling system would comprise a single (or N) compressor based chiller,
single primary pump and single (or N) air-conditioning modules in the critical space - all being fed from a
single path electrical power system that need not include redundancy.
An example of a fresh-air cooling system with adiabatic cooling would comprise a single (or N) inlet fan,
single (or N) supplementary cooling coil, single (or N) adiabatic cooling spray system and, where required,
powered louvres - all being fed from a single path electrical power system that need not include redundancy.
The supplementary cooling coils would feed N heat rejection systems.
6.2.4.3 Class 3: Single path (resilience provided by redundancy of components)
An example of a chilled water cooling system would comprise a redundant (N+1) compressor based chiller
system, redundant (N+1) primary pumps and redundant (N+1) air-conditioning modules in the critical space -
all being fed from a single path electrical power system that includes N+1 redundancy in key components.
Some passive and inherently reliable sub-systems (e.g. the chilled water piping) would not have redundancy
built-in and a failure in such an element would be considered major and would usually result in a loss of
cooling.
An example of a fresh-air cooling system with adiabatic cooling would comprise a redundant array (N+1) of
inlet fans, a redundant array (N+1) of supplementary cooling coils, single (or N) adiabatic cooling spray
system and, where required, powered louvres - all being fed from a single path electrical power system that
includes N+1 redundancy in key components.
Where water is used for humidification or adiabatic cooling then a redundant source, or on-site storage of
sufficient volume to meet the clients’ resilience requirements, shall be included in the design. All pumps and
water treatment plant (where required) shall have N+1 redundancy in key components.
6.2.4.4 Class 4: Multi-path resilience and concurrent repair/operate solution
An example of a chilled water cooling system would comprise a redundant (N+1) compressor based chiller
system, dual (N+1) primary pumps and redundant (N+1) air-conditioning modules in the critical space - all
being fed from a single path electrical power system that includes N+1 redundancy in key components but
also has a passive delivery path (with automatic or manual changeover switches). All passive sub-systems
(e.g. the chilled water piping) shall also have in-built path redundancy where a failure in such an element
would usually result in a loss of cooling albeit with a rapid (manual) substitution of the active path with the
passive path.
An example of a fresh-air cooling system with adiabatic cooling would comprise a redundant array (N+1) of
inlet fans, a redundant array (N+1) of supplementary cooling coils, a redundant array (N+1) of adiabatic
cooling spray systems and, where required, powered louvres - all being fed from a single path electrical
power system that includes N+1 redundancy in key components but also has a passive delivery path (with
automatic or manual changeover switches). Heat transfer from the supplementary cooling coils to the
external heat rejection system shall have N+1 redundant topology. If the heat rejection path is common then
a passive path shall be provided.

– 17 – EN 50600-2-3:2014
Where water is used for humidification or adiabatic cooling then a redundant source, or on-site storage of
sufficient volume to meet the clients’ resilience requirements, shall be included in the design. All pumps and
water treatment plant (where required) shall have N+1 redundancy in key components and a passive path for
delivery of water with manual intervention.
The environmental control system shall be designed such that loss of functional capability is limited to 10 min
in any one operating year.
6.2.4.5 Enhanced Class 4: Multi-path resilience, concurrent repair/operate, and fault tolerant
solution
An example of an active/active (2N) chilled water cooling system would comprise two segregated and
entirely separate (N) compressor based chiller systems, each with (N) primary pumps, separate (N) piping
systems and non-redundant (N) air-conditioning modules in the critical space - each system fed from its own
single path electrical power system that may or may not include N+1 redundancy in key components.
An example of a fresh-air cooling system with adiabatic cooling would comprise two cooling systems each
with a non-redundant array (N) of inlet fans, an array (N) of supplementary cooling coils, an array (N) of
adiabatic cooling spray systems and, where required, powered louvres - each system being fed from its own
single path electrical power system that may or may not include N+1 redundancy in key components. Heat
transfer from the supplementary cooling coils to the external heat rejection system need only have N
redundant topology. The heat rejection path shall not be common.
Where water is used for humidification or adiabatic cooling then two separate and redundant sources, or dual
on-site storage of sufficient volume to meet the clients’ resilience requirements, shall be included in the
design. If there is only one primary source of water then dual storage systems shall be included with as much
water capacity as needed to match the on-site autonomy of diesel fuel provision for the emergency electrical
generators. All pumps, piping system and water treatment plant (where required) shall have 2N redundancy,
each system fed by separate power systems.
6.2.5 UPS space
6.2.5.1 General
The requirements of this clause apply where the UPS equipment is not accommodated in the computer room
space.
For rotary UPS the requirements of 5.2.15 shall apply.
6.2.5.2 Class 2: Single path (no resilience)
The UPS space shall be ventilated/cooled by a single air-conditioning terminal or fresh-air fan that is rated to
supply the cooling capacity equal to the maximum possible power losses in the UPS and not exceed the
peak temperature supported by the chosen UPS, usually in the order of 40°C. A single failure in the cooling
plant exposes the UPS to over-temperature and shut-down/bypass with associated risk to the critical load.
6.2.5.3 Class 3: Single path (resilience provided by redundancy of components)
The UPS space shall be ventilated/cooled by an N+1 redundant air-conditioning terminal array or fresh-air
fans that are rated at N to supply the cooling capacity equal to the maximum possible power losses in the
UPS and not exceed the peak temperature supported by the chosen UPS. A single failure in the cooling
plant components shall not expose the UPS to over-temperature and shut-down/bypass with associated risk
to the critical load.
6.2.5.4 Class 4: Multi-path resilience and concurrent repair/operate solution
The UPS space shall be ventilated/cooled by two separate air-conditioning terminal array’s or fresh-air fan
arrays that are each rated to supply the cooling capacity equal to the maximum possible power losses in the

UPS and not exceed the peak temperature required by the chosen UPS. A complete failure in the cooling
plant of one path shall not expose the UPS to over-temperature and shut-down/bypass with associated risk
to the critical load. The two systems shall not share a common power system.
6.2.5.5 Enhanced Class 4: Multi-path resilience, concurrent repair/operate, and fault tolerant
solution
Not applicable.
6.3 Environmental control system capacity planning with respect to expansion
During the design phase the use of modular solutions providing capacity for the expected load with respect
to time shall be considered.
6.4 Environmental control sy
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