A PERIODIC PUBLICATION BY THE ABR CONSULTING
CONTACT US AT WWW.ABRCONSULTING.COM
NO. 01 VOLUME 03 - AUGUST 24, 2001
Budgeting For a Data Center
on a theme that we began in the last issue of our newsletter, and to answer
questions we received specific to data center construction costs, we present to
you a response that we prepared for a customer. Bob and Don, forgive me
for repeating information that I sent to you but the response deserves a wider
information below provides the construction costs plus it contains more in depth
descriptions of the “Tier” system concept.
1. Different Types (Tiers) of Data Centers
first thing that I discussed with you is the different types of data centers
(which I will refer to as “tiers”).
The tiers differ in the amount and type of redundancy that is built
into the environmental systems and the reliability factor (uptime) that is
expected from the facility (i.e. 99.95%, 99.96%, 99.99%, etc.).
tier structure described below was created by The Uptime Institute, an organization that is establishing standards for data center reliability. The chart below is an excellent resource for identifying the type of data
center that you are planning.
ABR differs slightly with the construction costs and will list our
construction cost ranges following
The Uptime Institute
tiered system that I referred to above was developed by The Uptime Institute®,
The Uptime institute developed this tiered classification approach to site infrastructure functionality
to address the need for a common benchmarking
standard. The Institute’s system has been under development for several years,
and includes measured availability figures ranging from 99.67% to more than
99.99% It is important to note that this range of availability is substantially
less than the current Information Technology (IT) expectations for “Five
Over the last forty years, data center designs have evolved through at least
four distinct stages, which are captured in the Institute’s classification
system. Tier I first appeared in the early sixties, Tier II in the seventies,
Tier III in the late eighties and early nineties, and Tier IV in 1994 with the
United Parcel Service Windward project, which was the first site to assume the
availability of dual-powered computer equipment. The Uptime Institute®
participated in the development of Tier III concepts and pioneered the creation
of Tier IV.
advent of dual-powered computer hardware in tandem with Tier IV electrical
infrastructure is an example of site infrastructure design and computer hardware
design simultaneously achieving higher availability. With the significant
improvements in computer hardware design currently being made, many data centers
constructed even in the last five years offer only Tier I, II, or III
functionality, falling far behind in their capacity to match the availability
offered by the Information Technology they support.
Defining the Tiers
The tier classification system involves several definitions. A site that can
sustain at least one “unplanned” worst-case site infrastructure failure with
no critical load impact is considered fault tolerant. A site that is able to
perform planned site infrastructure activity without shutting down critical load
is concurrently maintainable (fault tolerance level may be reduced during
concurrent maintenance). It is important to remember that a typical data center
site is composed of at least twenty major mechanical, electrical, fire
protection, security and other systems, each of which has additional subsystems
and components. All of these must be concurrently maintainable and/or fault
tolerant for the entire site to be considered concurrently maintainable and/or
Some sites built with fault tolerant System+System electrical concepts failed to
incorporate the mechanical analogy, which involves dual mechanical systems.
sites are classified Tier IV electrically, but only achieve a Tier II level
mechanically. The following list summarizes the characteristics of each Tier.
+ Tier I
Single path for power and cooling distribution, no redundant components, 99.671%
+ Tier II
Single path for power and cooling distribution, redundant components, 99.749%
+ Tier III
Multiple power and cooling distribution paths, but only one path active,
redundant components, concurrently maintainable, 99.982% availability.
+ Tier IV
Multiple active power and cooling distribution paths, redundant components,
fault tolerant, 99.995% availability.
The availability numbers have been drawn from industry benchmarking conducted by
The Uptime Institute and sites in the top 90th percentile (this means only 10%
of all sites performed at this level). The quality of human-factors management
is the most significant element separating top sites from all others.
Tier III Data Center
Tier I Data Center
A Tier I data center is susceptible to disruptions from both planned and
unplanned activity. It has computer power distribution and cooling, but it may
or may not have a raised floor, a UPS, or an engine generator. If it does have
UPS or generators, they are single-module systems and have many single points of
failure. The infrastructure should be completely shut down on an annual basis to
perform preventive maintenance and repair work. Urgent situations may require
more frequent shutdowns. Operation errors or spontaneous failures of site
infrastructure components will cause a data center disruption.
Tier II Data Center
Tier II facilities with redundant components are slightly less susceptible to
disruptions from both planned and unplanned activity than a basic data center.
They have a raised floor, UPS, and engine generators, but their capacity design
is “Need plus One” (N+1), which has a single-threaded distribution path
throughout. Maintenance of the critical power path and other parts of the site
infrastructure will require a processing shutdown.
level capability allows for any planned site infrastructure activity without
disrupting the computer hardware operation in any way. Planned activities
include preventive and programmable maintenance, repair and replacement of
components, addition or removal of capacity components, testing of components
and systems, and more. For large sites using chilled water, this means two
independent sets of pipes. Sufficient capacity and distribution must be
available to simultaneously carry the load on one path while performing
maintenance or testing on the other path. Unplanned activities such as errors in
operation or spontaneous failures of facility infra-structure components will
still cause a data center disruption. Tier III sites are often designed to be
upgraded to Tier IV when the client’s business case justifies the cost of
Tier IV Data Center
Tier IV provides site infrastructure capacity and capability to permit any
planned activity without disruption to the critical load. Fault-tolerant
functionality also provides the ability of the site infrastructure to sustain at
least one worst-case unplanned failure or event with no critical load impact.
This requires simultaneously active distribution paths, typically in a
System+System configuration. Electrically, this means two separate UPS systems
in which each system has N+1 redundancy. Because of fire and electrical safety
codes, there will still be downtime exposure due to fire alarms or people
initiating an Emergency Power Off (EPO.) Tier IV requires all computer hardware
to have dual power inputs as defined by The Uptime Institute’s Fault Tolerant
Power Compliance Specification Version 1.2.
3. ABR Information
A. Construction Costs
slightly from the graphic above. Our
per square foot costs are slightly lower and have a range of costs.
So much more needs to be known before a tight budget can be finalized.
Construction Costs (costs per sq.ft.)
Tier I $275-$350
b. Tier II $325-$450
c. Tier III $500-$700
d. Tier IV $700-$900
graphic above shows the Tier III centers as having a 12kV-15kV utility service
for power. We are noting that it is
not uncommon for data centers identified as Tier III to have 480/208 utility
service. For large campuses where
multiple buildings are served, the 12kV-15kV service would be appropriate.
NATIONAL ELECTRIC CODE PROPOSALS
TO REQUIRE REMOVING ABANDONED CABLE. WILL ADDITIONALLY LIST CMP-50 CABLE
The upcoming revision of the National Electric Code
(NEC®) may include accepted proposals that address two subjects with special importance
to communications cabling projects. Officially known as NFPA 70, the NEC
code book is published by the National Fire Protection Association
(NFPA®). The NEC is issued every 3 years after carefully reviewing
content and inserting updated changes. NEC 2002, the next issue of the NEC (NFPA 70)
is due for release by the NFPA in September 2001.
The first subject is abandoned cable. It has been proposed that any
abandoned cable (cable that is no longer in use or terminated) be removed.
If accepted and published with the NEC 2002 issue, this will most likely apply
to all building upgrades and renovations. If accepted and published,
expect city and municipal building inspectors to enforce this rule on any
project onto which they appear and inspect. Whether or not Fire Marshalls
choose to enforce this code on existing projects while on their annual visits
remains to be seen. (This could be interesting on older data center sites
where generations of bus & tag, SCSI and other cables are stacked on top of
each other with large amounts of abandoned cable on the bottom. The
abandoned cables were not removed for fear of dislodging critical cables.
If you've ever lifted a raised floor tile on an 18" floor and seen 12"
of cable, you know what we mean).
The second subject is the proposal to list CMP-50 cable as an approved
plenum-rated cable, most likely in Section 800. CMP-50 cable has passed
much more stringent flame spread tests and is far superior to normal CMP
specifications. If accepted and listed, this cable, if not too much more
than CMP will be the superior choice.
Both proposals were made to address the growing concern of excessive fuel loads
from the accumulation of cables in commercial buildings. The severity of
numerous commercial building fires has been attributed to large buildups of
electrical and communications cable.
IMPACT OF CMP-50 CABLE STANDARD
the National Electric Code permits non-plenum cable under a raised floor that
meets certain conditions. This is fully covered in our special article
on the subject (Using Non-Plenum Cable Under a
Raised Floor And, Meeting Code). We carefully reviewed the
documentation for CMP-50 cable and they specifically referred to plenum spaces
as those spaces above a false ceiling. Two errors here. First, not
all space above a false ceiling is a plenum. If the supply and return
air is ducted, its not a plenum. Second, the underfloor of a raised
floor system in a computer room is a plenum. Currently, as we stated in
the opening sentence, non-plenum cable is permitted in this plenum under
certain conditions. We are concerned that this may change to a point
where no matter what the code permits, CMP-50 cable will be the minimum
requirement. If the cable is cheap enough, we'll recommend this
MORE INFORMATION ON CMP-50 CABLE
DuPont is the manufacturer of the special materials in the
CMP-50 cable that permits the improved low flame performance. DuPont has
a most excellent description of CMP-50 cable on their website. They also
have a powerpoint presentation of the online material that you can download
Here's the link: www.dupont.com/teflon/cablingmaterials/cmp50/
17 CLOSER TO ADOPTION
Division 17 is closer to becoming
a reality. For those of you not familiar with Division 17, its the
proposed new section for the CSI MasterFormat™. Still don't
understand? Ever see the large book of construction specifications that
general contractors use on the construction projects? A highly
specialized and structured format is used nationwide in producing the
assembled documents. It's not the specifications themselves, its the
In 1963, the Construction
Specifications Institute (CSI) introduced a master format for assembling
construction specifications. Currently, there are 16 divisions to this
master format which the CSI has trademarked as MasterFormat. For
decades, all telecommunications specifications were placed within Division 16
(Electrical). And, why not? Telecommunications cables are
electrical cables albeit low voltage. However, in the past two decades,
telecommunications has become a monstrous industry in and of itself and its
inclusion in Division 16 is becoming burdensome. Speaking as Telecom
designs, we produce 2-3 sections within Division 16 and the electrical
engineers aren't thrilled. Plus, we already label our drawings as
"T" drawings instead of "E" drawings. This is not
officially permitted but we do it anyway.
In October 1999, a proposal was submitted to the CSI advocating the creation
and implementation of a Division 17 for telecommunications. Several
national associations have expressed their support for the proposal. For
us, we are already creating specifications under Division 17. We've even
produced an RFP standard for a national financial institution using Division
17. The next MasterFormat is due in 2002. We are hoping that this
new division is adopted.
From time to time, the ABR Consulting Group,
Inc. will e-mail you condensed information for the ever-changing and
every-dynamic world of designing, planning and relocating data centers, server
rooms, labs and other key IT/IS spaces. All you have to do is place your
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Contact us at www.abrconsulting.com
Phone: 925.872.5523 Fax: 916.478.2814