When designing a new data center or considering upgrading a site, one of the original reference sources is the Uptime Institute and its tier availability rating system, pioneered by Ken Brill in the early 1990s and formally introduced in 1995. And while not everyone subscribes to it officially, references to Tier 2, 3 or 4 are common among those seeking to ascribe a certain level of design or construction to a data center's overall...
availability or systems redundancy.
In 2005, the Telecommunications Industry Association (TIA), in conjunction with the American National Standards Institute (ANSI), created the TIA-942 Data Center Standard and issued the revised TIA-942-2 in March 2010. Then, in June 2010, the Building Industry Consulting Service International Inc. (BICSI) issued its standard 002-2010: Data Center Design and Implementation Best Practices.
So when designing a new data center or contemplating a major upgrade to an existing site, where should you turn for your reference standards? What differentiates these standards and their respective organizations?
The Uptime Institute and its tier standard
The Uptime Institute's tier standard of availability seeks to be more goal-oriented rather than a rigid technical specification of the way a data center should be designed and constructed, according to Julian Kudritzki, vice president of the Uptime Institute.
While the TIA 942 standard also has its own tier levels (1-4), Kudritzki said that what distinguishes the Uptime Institute's tiers is flexibility rather than specific requirements found in the TIA standards.
The Uptime Institute recently updated its standards with the introduction of its Operational Sustainability Standards and three additional ratings, defined as Gold, Silver and Bronze, which are intertwined with the Tier 1-4 rating. It goes on to state that the gold, silver and bronze ratings are awarded based on the success of data centers' operational practices.
However, there is an important obstacle to the Uptime standard. In order to obtain an official Uptime tier rating, an organization must have the Uptime Institute's professional consulting practice review and approve the plans of the facility or have an Uptime consultant visit the site to obtain an Uptime tier rating. As a result, to date, the Uptime Institute's directory of approved sites lists only 13 Tier 3 sites and four Tier 4 sites in the entire world. Perhaps it is for this reason that many designers, builders and operators have turned to the TIA-942 standard rather than engage the Uptime Institute to oversee and rate their projects.
TIA-942 and BICSI 002-2010
In contrast to the Uptime Institute's concept-based approach, the TIA-942-2 revision (a 40-page addendum to the original 140 pages), is very specific and detailed on its tier rating and the attendant requirements for each level of redundancy and availability. (Side note: TIA-942-1, issued in 2008, was a minor update focused only on coaxial cabling).
None of the three standards organizations are free of dependencies on other organizations. In some way, they each reference government standards, local codes and organizations such as the following:
ASHRAE: American Society of Heating, Refrigerating and Air-Conditioning Engineers
IEC: International Electrotechnical Commission
IEEE: Institute of Electrical and Electronics Engineers
ISO: International Organization for Standardization
NEC: National Electrical Code
NFPA: National Fire Protection Association
UL: Underwriters Laboratories
A particularly convenient feature of the TIA-924-2 update is that it clearly shows the changes from the original 942 standards, avoiding the need to compare the update to the original.
Besides cabling, other key details in the TIA tier standards are very specifically defined, covering physical construction, electrical power, cooling, monitoring security, redundancy, maintainability and commissioning.
The BICSI began in 1974 as an industry association to service the needs of telecommunications consultants. Like the TIA, it originally focused on cable plant design and installation. The new 223-page BICSI standards book, released in June 2010, is a compilation of best practices and recommendations as well as references to external organizations' standards, such as those from the American Society of Heating, Refrigerating and Air-Conditioning Engineers. However, BICSI 002-2010 is most heavily intertwined with the TIA-942 standard. The initial release of the BICSI 002-2010 data center standard is not completely finished. The electrical systems and telecommunications sections are still being finalized at this time.
With over 200 pages of technical details, it is far more specific than the Uptime guidelines and bears similarities to TIA-942. Unlike the standards from Uptime and TIA, the BICSI standards do not invoke a tier rating system. But the D006 draft release of the electrical systems section defines five classes of availability for data center electrical systems -- F0-F5. Although classes F1 through F5 seem to mimic the tier structure, class F0 describes a total lack of anything to protect the IT load from failure. Specifically, F0 is a single path with no UPS and no "proper IT equipment grounding." BICSI's Jeff Silveira indicated that the F0 designation is only meant to cover a server or network closet.
Jeff Silveira, Standards Director of BICSI, said that the new BICSI standard draws information from a several separate disciplines. "Our work complements what is written in a number of documents and standards and, where more information may be desired, points the way … It's not necessary to tell the architects, engineers and electricians how to do their job."
According to Jonathan Jew, a representative of the TIA, the BICSI standard is meant to be a best practices supplement to whichever telecommunications standard a facility uses. "BICSI 002, while providing best practices in a wide variety of subjects, requires that the designer use one of the base data center telecommunications standards, such as TIA-942, CENELEC EN 50174-2 or ISO/IEC 24764," he said.
The depth and breadth of both the TIA and BISCI standards vary a little in topic areas and are mostly in accordance with one another, with the exception of the emergency power-off (EPO) button.
The EPO button
The question of whether or not to use the EPO plagues many data center designers and operators. According to Uptime, it is not required unless mandated by local codes and is a likely and proven cause of downtime. The Uptime Institutes Tier Myths and Misconceptions webpage states: "Analysis of the Uptime Institute's Abnormal Incident Report database reveals that accidental EPO activation is a recurring cause of downtime. Uptime Institute Tiers does not mandate an EPO. Unless compelled by a local jurisdiction or code, Uptime Institute does not recommend EPO installation." The TIA concurs, explicitly stating in TIA-942-2, "Do not install if not required by authorities having jurisdiction."
However, while BICSI clearly recognizes the risk of an EPO, it recommends that "When not required by code, the owner must carefully balance the needs of business continuity with personnel and building safety." For those who chose to implement an EPO, BICSI specifically recommends a single-stage EPO for classes F0 and F1 and a three-stage EPO for classes F2-F5.
Data center energy efficiency
While the focus of all the standards is on reliability and availably, no discussion of today's data centers is complete without considering energy efficiency. The Green Grid has gained widespread recognition since its introduction in 2008. While it is not a standards organization, its power usage effectiveness (PUE) and data center infrastructure efficiency (DCIE) metrics have been adopted by the U.S. Environmental Protection Agency and many other countries and organizations worldwide. The Uptime Institute and TIA standards as well as the BICSI best practices do not directly address energy efficiency in the data center as part of a tier requirement, however, because it cannot be a defined as specific parameter. Nonetheless, it is indirectly indicated as a desirable ongoing goal for data centers.
The bottom line on data center standards
The Uptime Institute clearly has had the most long-term visibility since it was the originator of the tier system standard. However, the Uptime tier system has limited the number of actual certifications due to the consulting requirement and high costs. It has lost ground to the more clearly defined and easily available TIA-942 standard, which has been available for five years and has just been updated to reflect the current state of the data center. The recent entrance of BICSI, which has a large number of members, may have some additional positive impact on smaller data center and server room designs. With each iteration of the organizations' standards comes more widespread awareness, which will hopefully lead to an overall improvement in future data center design and construction.
ABOUT THE AUTHOR: Julius Neudorfer has been CTO and a founding principal of NAAT since its inception in 1987. He has designed and managed communications and data systems projects for both commercial clients and government customers.
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