ASHRAE Journal - February 2023 - 46

FEATURE
Report to Congress
on Server and Data
Center Energy
ASHRAE BOD
approves SPC 90.4
2011 - 2012
Effi ciency Public
Law 109-431
2007August
2
2010
90.1 removes
exemption for data
centers
90.1 mandated
economizers
(includes data
centers)
ASHRAE President
Ronald Jarnagin
selected as
Committee Chair
2012-
2013
2016
90.4-2016
published
SPC 90.4 moves
to continuous
maintenance and
becomes SSPC
90.4
FIGURE 2. Standard 90.4 development timeline.
these considerations also be required.
The Scope section of Standard 90.4 clarifi es the application.
It states, " this standard applies to
a. new data centers, or portions thereof, and their
systems;
b. new additions to data centers, or portions
thereof, and their systems; and
c. modifi cations to systems and equipment in existing
data centers or portions thereof. "
The Scope also says, " The provisions of this standard
do not apply to
a. telephone exchanges,
b. essential facilities, and
c. information technology equipment (ITE). "
Understanding the exceptions is crucial. Telephone
exchanges are not governed, but if telephone exchanges
become data centers (as many do) and parts of them are
no longer classifi ed as Common Carriers, then Standard
90.4 does apply. Likewise, " essential facilities " must
meet specifi c requirements. Most data centers are classifi
ed as " mission critical, " but that does not automatically
make them " essential facilities. " The clarifi cations are
included in the standard. Lastly, the standard does not
attempt to impose effi ciency requirements on the actual
data processing equipment (computers, processors,
servers, switches, routers, etc.), more properly known as
information technology equipment (ITE). It applies only
to the environment and related infrastructure in which
the ITE is operated. Design engineers need to quantify
46
ASHRAE JOURNAL ashrae.o rg F E B R U A RY 2 0 2 3
the maximum ITE load (and day-one minimum ITE
load), but there are no ITE energy effi ciency requirements
for the actual electronic equipment.
Standard 90.4 does not just apply to new greenfi eld
projects. It also applies to data center expansions and
modifi cations to infrastructure. Data centers are often
pre-planned with signifi cant expansions engineered
into the original designs. Further, as data centers and
respective technologies continue to evolve, existing
sites can require upgrades and modifi cations. It follows,
therefore, that facility expansions as well as system
and equipment modifi cations are the norm and should
adhere to the latest effi ciency requirements.
After Title, Purpose and Scope, the most important
part of the standard is Defi nitions, as listed in Section 3,
and two of the most important defi nitions are those for
" data centers " and " computer rooms. " The delineation
between these two classifi cations resulted from collaboration
between the SSPC 90.1 committee and SPC
90.4 committee. It was agreed that a computer room is
defi ned as " a room or portions of a building serving an
ITE (information technology equipment) load less than
or equal to 10 kW or 20 W/ft2 (215 W/m2) of conditioned
fl oor area. " A data center, on the other hand, is defi ned
as " a room or building, or portions thereof, including
computer rooms being served by the data center systems,
serving a total ITE load greater than 10 kW and
20 W/ft2 (215 W/m2) of conditioned fl oor area. Why is
this distinction so important? Because computer rooms
90.4-2019
published
Lower maximum
compliance values
for MLC and ELC
2019
2020
90.1 approves
using 90.4 as
the alternate
compliance path for
data centers
State of Washington
formally adopts
90.4-2016 in State
Energy Code
90.4-2019
adopted by the ICC
2021
2022
90.4-2022
(published
in 2023)
New ELC updates
and example
calculations
included for users
to follow
http://ashrae.org
ASHRAE Journal - February 2023

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