CRITICAL ISSUES
Power Quality and Reliability
Building A Data Center:
A Construction Minefield
Critical construction projects require special expertise
BY MIKE HELLMAN, SIEMENS ENERGY & AUTOMATION
W
hile every design
and construction
project presents
its own unique
set of problems,
few can rival the myriad of complex
challenges involved in the construction of a modern data center, data
farm, or telecom hotel. Although
differing greatly in square footage
and configuration, all are essentially
host sites for some of the largest and
most powerful computer servers in
the world. Many are web-hosting
facilities hatched to serve the explosive growth of the Internet. Some
are in downtown high-rise office
buildings, others in formerly abandoned warehouses near rail yards.
Still others are in suburban office
parks. But there’s a reason for each
location, just one of the many variables in the complex issues to balance when planning a data farm.
“While the growth of the last
few years has slowed, e-commerce
is still growing. During the Internet
boom everyone wanted a piece of
the action, and you couldn’t even
find the building materials or hardware you needed,” said Bruce W.
Bleser, director of Mission Critical
Facilities for Black & Veatch, a
Kansas City, MO,-based engineering and construction firm with over
25 years of data center experience.
Bleser notes there are three main
types of data centers: POPs, or
point of presence, which provide
access to fiber; Internet data centers
(IDCs) like Sprint E|Solutions, Exodus, Genuity, and several others
that lease rack space or provide
fully managed services; and, third,
enterprise facilities for huge collections of data by customer-owners
such as Wal-Mart or insurance
companies. All however, share similar requirements.
Power and Fiber
“We have helped to build data
centers in almost every type of
building you can imagine,” said
Julio Herdocia, a principle at MTH
Engineers in Santa Clara, CA, “and
it can be a real challenge. But there
are always two main ingredients,
power and fiber.” Data centers consume huge amounts of power,
sometimes so much they aren’t welcome in some communities. The
Wall Street Journal recently report-
ed that a new 45,000-square-foot
data center planned in Sunnyvale,
CA, by Qwest Communications
wouldn’t receive power until 2002
by the local utility, PG&E. “They
are using enormous amounts of
power,” said Keith Reed of PG&E.
In just one year the utility received
requests from data centers for
Just the availability
of sufficient power
for a data center
begs the bigger
question: what is the
quality of that power
and is it reliable?
enough power equal to that used by
1.2 million families.
The Yankee consulting group
predicted power supplies in areas
like Santa Clara would have to
double in three years, just to supply
power for data centers. Considering the power situation in California, that isn’t likely to happen.
Some local utilities are making
farms pay a surcharge for their
high power needs. Bob Royer of
Seattle City Light told The Wall
Street Journal, “We don’t want the
old economy paying for the effects
of the new economy.” Data centers
must pay additional costs to locate
in his town.
Critical Power
Just the availability of sufficient
power for a data center begs the
bigger question: what is the quality
of that power and is it reliable?
“This is the critical question,” says
MTH’s Herdocia. “Data centers
contract with their customers for
high rates of reliability—they can’t
go down. We reference the six 9s of
reliability or 99.9999% of uptime.
That means over a year’s time, the
data center will experience only 30
seconds of downtime per year. At
this point you are talking a lot of
redundancy, with battery back ups,
then parallel generators. It gets to a
point where you are designing a
system that is so complicated it is
no longer economically feasible,”
Herdocia said.
In fact, however, the “only” thirty seconds of downtime per year
noted in the six 9s is not a real-time
figure. When all backup systems do
fail, it can take hours, even sometimes days, to restore the integrity
of the system and bring it back up
to normal operations. Six 9s is simply a statistical measurement, not
what happens in reality.
“You must consider the N
(norm) plus 1, 2 or 3 (redundancy),
a formula for ultimate reliability vs.
design/build expense,” he said. And
each complete redundancy you add
to the design can double the total
amount of floor space needed.
Bleser of Black & Veatch says he
has heard of power demands of over
300 watts per square foot (W/ft2). “I
would say the average for IDCs is
approaching 200 W/ft2 and 75-100
W/ft2 for enterprise data centers.
That is a lot of concentrated power.”
Still, data centers can be very
profitable. Many new installations
make money after just a few
months. Revenue can equal as much
as $1200 per ft2, about three times
that of a regional shopping center.
These numbers can make developers and investors very happy.
Down by the Tracks
If reliable power is available; the
next consideration in siting a data
center is access to fiber optic
cable—and lots of it. Ironically,
Row after row after row of servers in a data center bite into the facility’s power
distribution capability—as much as 300 W/ft2, according to some reports. Revenue can equal as much as $1200 per square foot, about three times that of a
regional shopping center.
According to Bleser of Black &
Veatch, nearly every watt going
into the computer produces heat,
which must be disbursed through
the HVAC system. “As a rule of
thumb, you need to double the total
power used by the computers to
approximate the power required for
the HVAC systems and the balance
of the facility,” Bleser said. The
racks, fans, and raised floors can
usually be accommodated in older
warehouse locations, but sometimes the entire roof must come off.
And then there is the problem of
where to locate the large (and multiple) generators needed and the
If reliable power is available; the next
consideration in siting a data center is
access to fiber optic cable—and lots of it.
this requirement often brings the
new economy in touch with the old.
Fiber optic cables are often located
along rail right-of-ways. The existing old warehouse buildings near
these tracks can often be refurbished to house a new data center.
They offer a number of advantages
as well as some unique problems.
The high ceilings and open spaces
allow for an open interior for racks
of computers and the huge amount
of HVAC needed to cool them.
fuel tanks that serve them. Up to 24
hours of fuel is stored to cover a
potential utility failure.
Crisis Planning
Data centers must be installed in
a secure location with 24 /7 controlled access. A plan to perform
regular scheduled maintenance
without interruption of service must
be in place. Fire protection, the ability to cool the equipment during an
interruption, and a fortressing plan
December 2001
for any conceivable disasters,
including earthquakes and even
chemical rail car leaks must be
accounted for. Any of these can
bring a data center down, and not
just for thirty seconds. Even the
availability and delivery schedule
of tankers with fuel for the generators must be evaluated in the design
plan. A recovery plan for any conceivable type of emergency is the
final chapter in this crisis planning.
If all this sounds like you’re
building a war room for the U.S.
military, you’re not far wrong.
“Information has become the new
utility of the 21 st century”, said
Bleser. “And highly reliable and
highly secure data centers are the
cornerstone upon which this new
utility is being built.” eun
About the author: Mike Hellmann
is marketing manager, Critical
Power Markets, for Siemens Energy & Automation, Atlanta. His
responsibilities include identifying
mission critical facilities—including
data centers, web hosting, collocation, financial and telecommunications facilities—for a broad range
of Siemens technologies, typically
working with consultant engineers, developers, general and
electrical contractors, OEMs, and
end users. He received a bachelor
of science degree in engineering
from Clarkson University.
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