from -40°C to +65°C (-40°F to +149°F) and Class 3 from
-40°C to +70°C (-40°F to +158°F). Equipment categorized
with these temperature ratings is safe to operate without
cooling methods that require chilled gas or liquid. Any
outdoor equipment outside of this range is considered
non-temperature hardened equipment and requires active
cooling to maintain its inlet air condition to meet its specific
operating temperature and humidity range. Equipment
deployed with a liquid or immersion cooling system
must meet its hardware compatibility requirement.
Server, storage, and switch gear power levels are
on the rise, thereby driving higher power dissipation
in racks and making cooling more of a challenge. There
are differing views as to what the average power levels per
rack are today and will be in the future. This complicates
things further because ICT professionals do not know all
the use cases planned in the new 5G network, which will
drive processing power, the amount of storage and the
associated switches that connect these devices to the
network fabric.
If rack power levels will be in the range of 10 to 20
kW per rack for the next five or even ten years, EDCs
can likely employ more traditional cooling methods and
take advantage of an established supply chain that affords
scale deployments and well-understood cost models for
not only the cooling equipment, but also for the servers,
storage devices and switch gears.
However, if rack power densities
surpass the 20 kW level in the near
future, then developing and deploying
EDC infrastructure with the more
traditional cooling methods that only
support less than 20 kW per rack
would decrease performance, efficiency
and flexibility. If rack densities
are greater than 20 kW per rack, the
industry should be driving technology
partners and a supply chain
to support the need for these newer
cooling methods and large-scale
deployments.
From classroom audio to campus-wide communication, FrontRow makes
communication effortless in any learning environment. We offer superior
Safety & Emergency
October/November/December 2020 I 43
Allowable ranges, depending on equipment, extend
the temperature range to as wide as 5°C to 45°C (41°F
to 113°F) for A4.
• A1: 15°C to 32°C (59°F to 89.5°F)
• A2: 10°C to 35°C (50°F to 95°F)
• A3: 5°C to 40°C (41°F to 104°F)
• A4: 5°C to 45°C (41°F to 113°F)
For equipment deployed in the traditional data center
environment, ASHRAE TC9.9 recommends new networking
equipment designs to be front-to-rear airflow rated
to a minimum of ASHRAE Class A3 (40°C) and preferably
ASHRAE Class A4 (45°C). For networking equipment
where the chassis does not span the full depth of the rack,
it is recommended to have an airflow duct that extends
to the front face of the rack. Furthermore, ASHRAE TC9.9
recommends the equipment be designed to withstand
a higher inlet air temperature than the data center cooling
supply air; this applies if the equipment is installed in
an enclosed space that does not have direct access to the
data center air cooling stream or the equipment has a sideto
side air flow configuration inside an enclosed cabinet.
Temperature hardened equipment is critical for the
outdoor application with limited cooling capacity. Telcordia
GR-3108 General Requirements for Network Equipment
in the Outside Plant classify allowable ranges as Class 2
Integrated Network
Communications for
Educational Applications
solutions that are simple and easy to manage.
Campus Communication
Device Management
LLeeaarrnn mmoorree aatt wwwwww..ggooffrroonnttrrooww..ccoomm
Communication
Classroom Audio
/www.gofrontrow.com