NO. 01  VOLUME 03 - AUGUST 24, 2001


 Budgeting For a Data Center Construction Project

Continuing 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 audience.  

The 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

The 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.). 

The 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 

2.     The Uptime Institute Information 

The 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 Nines.”

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.

The 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 fault tolerant.

Some sites built with fault tolerant System+System electrical concepts failed to incorporate the mechanical analogy, which involves dual mechanical systems.  Such 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% availability.

+ Tier II
Single path for power and cooling distribution, redundant components, 99.749% availability.

+ 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 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
Redundant Components

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.

Tier III Data Center
Concurrently Maintainable
Tier III 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 additional protection.

Tier IV Data Center
Fault Tolerant
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

We differ 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. 

1.     Construction Costs (costs per sq.ft.)

a.   Tier I        $275-$350
b.   Tier II       $325-$450
c.   Tier III      $500-$700
d.   Tier IV      $700-$900 

B.     Utility Voltage

The 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. 


 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.   


Currently, 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 anyway.  


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 for free.  

Here's the link: www.dupont.com/teflon/cablingmaterials/cmp50/


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 format.  

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.  



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