ETSI TR 102 489 V1.3.1 (2013-06)

Environmental Engineering (EE); European telecommunications standard for equipment practice; Thermal management guidance for equipment and its deployment

RTR/EE-01030

General Information

• Status: Published
• Publication Date: 26-Jun-2013
• Technical Committee: EE 1 - EE Environmental Conditions
• Current Stage: 12 - Completion
• Due Date: 15-Jul-2013
• Completion Date: 27-Jun-2013
• Mandate: M/462

Standards Content (Sample)

ETSI TR 102 489 V1.3.1 (2013-06)






Technical Report
Environmental Engineering (EE);
European telecommunications standard for
equipment practice;
Thermal management guidance for
equipment and its deployment

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2 ETSI TR 102 489 V1.3.1 (2013-06)



Reference
RTR/EE-01030
Keywords
Energy Efficiency, environment,
equipment practice, rack
ETSI
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© European Telecommunications Standards Institute 2013.
All rights reserved.

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ETSI

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3 ETSI TR 102 489 V1.3.1 (2013-06)
Contents
Intellectual Property Rights . 5
Foreword . 5
Abstract . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 ARCM integration overview . 8
5 Subrack integration in the same ARCM . 8
5.1 Configuring equipment in an ARCM . 8
5.1.1 Subrack location . 8
5.1.2 Cabling . 9
5.2 Mechanical structure of ARCM . 9
5.2.1 Opening geometry for the airflow . 9
5.2.2 Equipment fastening in the ARCM . 9
5.2.3 Doors . 10
5.3 ARCM cooling issues . 10
5.3.1 Cooling equipment including fans . 10
5.3.2 Air Cooling techniques . 10
5.3.3 Air filtering . 10
5.4 Impact of the implementation of subracks in an ARCM . 11
5.5 Impact of the temperature on equipment reliability . 12
6 ARCM integration in the same telecommunications equipment or Data center room . 12
6.1 Positioning the ARCM in a room . 12
6.1.1 Room layout. 12
6.1.2 Cabling . 13
6.1.3 Cooling systems . 14
6.2 Mechanical structure of ARCMs in the rows . 15
6.2.1 Opening geometry for the airflow . 15
6.3 Cooling systems for a room . 15
6.3.1 General design considerations . 15
6.3.2 Cooling techniques . 15
6.3.2.1 Passive cooling . 15
6.3.2.2 Warm air extraction (without cool air) . 16
6.3.2.3 Fresh air supply with natural release via pressure relief ventilators . 17
6.3.2.4 Cool air blowing (with or without relative humidity control) . 18
6.3.3 Room air paths . 20
6.3.3.1 Room air supply . 20
6.3.3.1.1 Free blow . 20
6.3.3.1.2 Overhead distribution . 20
6.3.3.1.3 Raised floor distribution . 21
6.3.3.2 Return air path . 21
6.3.3.2.1 Direct return to side walls at side/end of room . 21
6.3.3.2.2 Overhead return . 22
7 Thermal evaluation of the equipment/room architecture . 22
Annex A: Examples of cooling systems in an ARCM in use prior to EN 300 119-5 . 24
A.1 Single subrack cooling . 24
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4 ETSI TR 102 489 V1.3.1 (2013-06)
A.1.1 Air outlet located at the top of the ARCM . 24
A.1.2 Air outlet located at the front of the ARCM . 25
A.2 Multiple subrack cooling . 26
A.2.1 Serial cooling . 26
A.2.2 Parallel airflow with air inlet located at the front or the bottom of the ARCM . 27
A.2.3 Parallel airflow with air inlet located at the sides of the rack . 29
A.3 300 mm cabinet ARCM thermal solution . 30
A.3.1 Current 300 mm ARCM thermal solutions . 30
A.3.2 Alternative 300 mm cabinet solution. 31
A.3.3 Simulation test result about proposed thermal solution . 32
A.3.3.1 Mockup configuration. 32
A.3.3.2 Component test result . 33
A.3.4 Air deflector design . 33
A.3.4.1 Key factors in air deflector design . 33
A.3.4.2 Different air deflector mockup test . 33
Annex B: Example of ARCM cooling systems in a room . 36
B.1 Room - serial cooling . 36
B.2 Room - parallel cooling . 36
B.3 ETSI 300 mm ARCM in Central Office . 37
B.3.1 ETSI 300 mm ARCM solution . 37
B.3.2 ETSI 300 mm ARCM in CO . 38
B.3.3 Alternative ETSI 300 mm ARCM instalment in CO . 39
B.3.3.1 Simulation equipment configuration . 39
B.3.3.2 Simulation results . 40
B.3.3.3 Proposed CO arrangement . 41
B.3.3.4 300 mm ARCM in CO simulation . 42
Annex C: Bibliography . 44
History . 45

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5 ETSI TR 102 489 V1.3.1 (2013-06)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Environmental Engineering (EE).
The present document applies to all telecommunications racks/cabinets, miscellaneous racks/cabinets and subracks
forming part of the public telecommunications network and defined in EN 300 119-1 [i.3], EN 300 119-2 [i.4],
EN 300 119-3 [i.5], EN 300 119-4 [i.6] and EN 300 119-5 [i.7]
The document applies also to telecom and data center room istallations.
Abstract
It is often necessary to integrate different subracks into the same rack/cabinet and different racks/cabinets into a
common equipment room sharing the common room environment. The integration between equipment and the room is
increasingly more important. The present document is intended to provide assistance in integration of equipment and
room environment to ensure that the equipment has the required environment and that each equipment rack/cabinet is
not detrimental to the other equipment in the locality.
It should be an aid for all integrators and designers with their different elementary knowledge to integrate.
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6 ETSI TR 102 489 V1.3.1 (2013-06)
1 Scope
The present document is an aid for all integrators of Information and telecommunication Technologies (ICT) equipment
to minimize thermal problems. It establishes recommendations for the thermal management of racks/cabinets,
miscellaneous racks/cabinets and locations.
The document considers telecommunication Central Office (CO) and Data Centers (DC) locations.
The present document considers only the thermal factors. The integrator should consider the thermal factors in
conjunction with the EN 300 019-1-3 [i.1] and other non-thermal factors.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI EN 300 019-1-3: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1-3: Classification of environmental
conditions; Stationary use at weatherprotected locations".
[i.2] CENELEC EN 60950-1 (2006): "Information technology equipment - Safety - Part 1: General
requirements".
[i.3] ETSI EN 300 119-1: "Environmental Engineering (EE); European telecommunication standard for
equipment practice; Part 1: Introduction and terminology".
[i.4] ETSI EN 300 119-2: "Environmental Engineering (EE); European telecommunication standard for
equipment practice; Part 2: Engineering requirements for racks and cabinets".
[i.5] ETSI EN 300 119-3: "Environmental Engineering (EE); European telecommunication standard for
equipment practice; Part 3: Engineering requirements for miscellaneous racks and cabinets".
[i.6] ETSI EN 300 119-4: "Environmental Engineering (EE); European telecommunication standard for
equipment practice; Part 4: Engineering requirements for subracks in miscellaneous racks and
cabinets".
[i.7] ETSI EN 300 119-5: "Environmental Engineering (EE); European telecommunication standard for
equipment practice; Part 5: Thermal management".
[i.8] ETSI EN 300 386: "Electromagnetic compatibility and Radio spectrum Matters (ERM);
Telecommunication network equipment; ElectroMagnetic Compatibility (EMC) requirements".
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7 ETSI TR 102 489 V1.3.1 (2013-06)
[i.9] IEC TR 62380: "Reliability data handbook - Universal model for reliability prediction of
electronics components, PCBs and equipment".
[i.10] Recommendation ITU-T L.1300: "Best practices for green data centers".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
ambient: spatial maximal temperature of the air entering the rack/cabinet
NOTE: As defined in EN 300 019-1-3 [i.1].
cabinet: free-standing and self-supporting enclosure for housing electrical and/or electronic equipment
NOTE: It is usually fitted with doors and/or panels which may or may not be removable.
equipment: equipped subracks, racks/cabinets and miscellaneous racks/cabinets
integrator: end user/operator of telecommunication or IT equipment or their agent
NOTE: For example, an equipment manufacturer could be an operator's agent.
micro-climate: conditions found within the rack/cabinet/miscellaneous rack/cabinet creating a local ambient for the
subrack
NOTE: In practice this will typically result in elevated temperatures and reduced relative humidities to those
quoted in EN 300 019-1-3 [i.1].
Miscellaneous Rack/Cabinet (MRC): cabinet that accommodates subracks of several different types of equipment and
suppliers
NOTE: It is freely configurable by the Integrator.
rack: free-standing or fixed structure for housing electrical and/or electronic equipment
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Air Cooling
AHU Air Handling Unit
ARCM Any Rack, Cabinet and Miscellaneous rack/cabinet
CFM Cubic Feet to Minute
CO Central Office
CRAC Computer Room Air Conditioner
DC Data Centre
DT Data Temperature
EMC Electro Magnetic Compatibility
HVAC Heating, Ventilation & Air Conditioning
ICT Information and Communication Technology
MRC Miscellaneous Rack/Cabinet
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8 ETSI TR 102 489 V1.3.1 (2013-06)
4 ARCM integration overview
The integration can be broken down into:
• Positioning equipment in ARCMs including routing the cables.
• Analysing the possible impact of thermal issues on the configuration of racks/cabinets (e.g. location of
racks/cabinets) and MRCs (e.g. location, openings, placement of baffles).
• Providing the cooling solutions.
During the integration the following parameters have to be taken into account:
• The available volume.
• The maximum ambient temperature/micro-climate.
• The provision of coherent air flow to avoid hot spots.
• The functional thermal limits of equipment.
• The cabling space.
The overall cooling effectiveness needed depends in principle on the type of equipment to be cooled and thermal
requirements to be complied with.
Special attention should be taken to check the impact of the installation of different equipment in the same ARCM on
their functional thermal limits.
It is often very helpful to check, by suitable hand calculation, thermal simulation and measurement, whether the
integration is applicable for the purpose.
5 Subrack integration in the same ARCM
5.1 Configuring equipment in an ARCM
This activity consists of choosing how to combine the different subracks and the cabling in the ARCM.
5.1.1 Subrack location
This phase consists of positioning the different subracks in the ARCM.
The distribution of subracks should take into account the following parameters:
• Maximum power dissipated by the equipment for the maximum traffic load or its intended operational state.
For instance, knowledge of the maximum power dissipated will allow the integrator to locate the highest
dissipating subracks at the top of the ARCM in order to minimize the increase of temperature experienced by
the other subracks.
• Subracks working maximum temperature: For example, subracks, which withstand high temperature can be
installed at upper part of the ARCM (where generally the temperature is the highest).
• Thermal restrictions of each subrack. If possible, place the most restrictive subrack in an area not heated by
other subracks, for example, at the bottom in an ARCM with natural convection cooling system, or in an area
receiving fresh air with as high an air velocity as necessary.
• The position and area of air inlet and air outlet for the different subracks. The porosity of the surface and the
obstacles to the airflow in front of the ventilation surface should also be taken into account.
• Air inlet velocity, air outlet velocity of different subracks and estimated air outlet velocity of the ARCM.
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9 ETSI TR 102 489 V1.3.1 (2013-06)
• Air velocity inside the ARCM: This should be enhanced as much as possible, by means of subrack distribution
or additional subracks, e.g. fans, baffles, etc.
• Environmental class according to EN 300 019-1-3 [i.1] (for instance maximum air ambient temperature).
• Estimated direction of the airflow inside the ARCM. It is not recommended to have in the same ARCM two
subrack types which blow the air in the opposite direction.
• Recirculation of the air. Where possible, the recirculation of air between subracks should be avoided, unless
the design is specifically for serial cooling of the subrack. The risk of recirculation is higher when subracks
with different airflow paths are installed together in the ARCM. For instance, where the increase of
temperature is significant, the hot air exhausted by a subrack should be prevented from being reused to "cool"
another one. Check also the possibility of introducing additional elements to enhance the airflow, such as
baffles (to guide the air flows), vertical covers (to improve the performance of the convection, natural or
forced), plates (to separate flows and minimize re-circulation).
It is sometimes necessary to assign some space between two adjacent subracks to accommodate the location of the air
inlets or the air outlets. This information is generally provided by the manufacturers and detailed in the user's guides.
5.1.2 Cabling
It is recommended that cables within the ARCM are routed in order to minimize the impact on the airflow, without
restricting access to other subracks and making best use of the side cable access channels.
Cables and cable bundles can represent a significant obstruction to airflow. When undertaking an analysis of thermal
performance accounting for airflow in an ARCM it is important that the analysis takes into account the location of
significant amounts of cabling (or wave guides) along with the significance of their obstruction.
5.2 Mechanical structure of ARCM
The thermal issues may have an impact on the mechanical structure of the ARCM, i.e.:
• Opening geometry definition.
• Equipment fastening in the rack.
• Definition of the doors and side panels.
This may lead to the choice of a new kind of ARCM (well adapted to the specific application) or to reuse an existing
product (generally, in this case, a compromise has to be found between requirements and performance of the ARCM).
5.2.1 Opening geometry for the airflow
To dissipate the power from the equipment the following parameters have to be considered:
• Position of openings.
• Shape of openings.
• Area and porosity of openings.
• Airflow direction due to the shape of the grid (with or without deflector of air inlet or outlet).
• Air inlet and air outlet temperature.
NOTE: In case of shielded racks, the openings may be well adapted to equipment frequencies.
5.2.2 Equipment fastening in the ARCM
The fastening elements should not obstruct the air circulation. For instance, in the case of transversal cooling, the
mounting brackets should be well designed to allow the subrack to be cooled. For ETSI compliant equipment this
should already be the case.
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10 ETSI TR 102 489 V1.3.1 (2013-06)
5.2.3 Doors
When it is necessary to cool the subracks, cabinet doors, when present, can be punched with a lot of small holes or a
grid may be placed at lower part of the door, allowing air access to a front ventilation channel. The degree of
perforation may be determined using any of the assessment techniques identified in clause 4.
5.3 ARCM cooling issues
It is a primary requirement for all equipment to be cooled by natural convection. The mechanical architecture of the
ARCM should be designed to promote natural convection. Assisted cooling methods should be employed only when
natural convection methods are unable to deal with the relevant heat dissipation.
While defining the cooling issues of ARCM the integrator may check the different cooling possibilities:
• What types of cooling techniques have to be used?
• Is natural convection sufficient to provide enough cooling for the equipment and to ensure that the temperature
of the issuing air does not exceed 75 ºC (in accordance with EN 60950-1 [i.2]) in worst-case conditions
(specified in the EN 300 019-1-3 [i.1])?
• Are additional fan trays necessary to supply/extract the air to/from the ARCM?
• Is air filtration necessary?
5.3.1 Cooling equipment including fans
During the configuration of the cooling equipment, the following issues have to be taken into account:
• Power supply interface requirements.
• EMC performance (e.g. voltage dips and spikes generated into the power network).
• Acoustic noise.
• Safety requirements (including fire protection).
5.3.2 Air Cooling techniques
Many cooling solutions already exist but they fall into two main categories:
• Serial cooling.
• Parallel cooling.
Annex A presents cooling system examples. Other approaches are possible. The present document helps the integrator
to mix different equipment in an ARCM.
5.3.3 Air filtering
In some instances (see EN 300 019-1-3 [i.1]) air filters (normally provided at the room level) could be required at the
equipment inlets. Where air filters are used, precautions should be taken in order to clean or replace them periodically.
If the filter is not cleaned or replaced, the micro-climate air inlet temperature for the subracks can increase dramatically,
or the air volume through the equipment be reduced and these changes in ventilation performance
...