Learn more about the Tier Classification System courtesy of the Uptime Institute, a vendor‑neutral organization which focuses exclusively on the data center business.


Have you ever gone to see a movie that had so much hype around it from noted reviewers, you were surprised when it was one of the worst movies you’d ever seen? This has happened more than once for me, including a flick last summer starring some of Hollywood’s A-list celebrities. I couldn’t believe such popular actors would participate in such a horrible movie that lacked any sort of direction.  

In the movie industry, there’s no set ratings scale for movies outside of the glitzy awards shows that celebrate top performances. In the data center industry, though, enterprises and service providers have the benefit of the Tier Classification System courtesy of the Uptime Institute, a vendor‑neutral organization which focuses exclusively on the data center business. The Tier System is the global standard for third-party validation of data center critical infrastructure and effectively evaluates data center infrastructure in terms of a business’ requirements for system availability, not only the building itself.  

Some business people hear about Tiers and aren’t sure what it means when a facility is referred to as Tier II or Tier III. Tier Certification applies not only to how a data center is designed, Tier Certified Design, but also how it’s built, Tier Certified Facility. It’s a performance-based evaluation of a data center’s specific infrastructure performed solely by Uptime Institute. It ensures that a data center has been constructed as designed, is capable of meeting the defined Tier requirements and can provide clear validation of its infrastructure, resiliency and capabilities.    

The Tier Classification System is comprised of the following four levels:  

Tier I – Basic Capacity: Tier I infrastructure includes a dedicated space for IT systems, an uninterruptible power supply (UPS) to filter power spikes, sags and momentary outages, dedicated cooling equipment that won’t get shut down at the end of normal office hours and an engine generator to protect IT functions from extended power outages.  

Tier II - Redundant Capacity Components: Tier II facilities include redundant critical power and cooling components to provide select maintenance opportunities and an increased margin of safety against IT process disruptions that would result from site infrastructure equipment failures. The redundant components include power and cooling equipment such as UPS modules, chillers or pumps and engine generators.  

Tier III - Concurrently Maintainable: A Tier III data center requires no shutdowns for equipment replacement and maintenance. A redundant delivery path for power and cooling is added to the redundant critical components of Tier II so that each and every component needed to support the IT processing environment can be shut down and maintained without impact on the IT operation.  

Tier IV - Fault Tolerance: Tier IV site infrastructure builds on Tier III, adding the concept of fault tolerance to the site infrastructure topology.  

Benefits of Tier Certification include reduced risk, an independent benchmark and verification of data center quality, prevention of over or underinvestment, project validation and the availability of a framework to evaluate enterprise and service provider facilities. The Certification encourages innovative engineering and unique operations programs, allows for client preferences by focusing on outcome and is adjudicated by data center experts, not professional auditors.  

While the Tier Rating System examines and certifies the level of resiliency in the design and actually construction of a data center and its critical systems, the M&O Stamp complements the Tier system and focuses on the staff and daily operational practices of a data center.  

The Uptime Institute has expanded the Tier Certification program to include the operational elements of the M&O program, in its Tier Standard: Operational Sustainability, which provides data center owners, operators and managers with the prioritized behaviors and risks intrinsic to data center operations and serves as an essential guide for effective and efficient operations. As the IT industry moves further into the cloud and IaaS mode of IT service delivery, end-users have less control over the data center infrastructure than ever before. Tiers and operational sustainability offer comprehensive, third-party assurance that the underlying data center infrastructure is designed and operated to the customer’s performance requirements (SLA). Therefore, enterprises are increasingly stipulating Tier Certification and Uptime’s Management and Operations (M&O) Stamp of Approval in RFPs to data center service providers.  

Even though achieving Tier Certification may seem like a good business decision, many of the more than 10,000 data centers globally haven’t utilized the program. Cyxtera boasts five Tier III‑certified facilities and has gone beyond that recently to obtain the Tier Certification in Operational Sustainability. There has been confusion in the industry generated by the use of the term, “tier III”, to refer to any data center with N+1 or better level of resiliency in its critical systems, even if the facility has not undergone the Uptime Tier Rating certification.  Be aware that a provider that tells you their data center is “tier III”, if it hasn’t been certified, you do not have a third party validation that the facility is indeed constructed to the level of resiliency your business requires.  

Just a few years ago, we stepped up and set a new bar in terms of M&O Stamps of Approval with an intent to pursue that achievement across our data center portfolio. We currently hold M&O Stamps in over 50 data centers, more than any other provider.  

Though some providers might tell you they’re Tier III-certified, it’s best to do your own research to verify that claim. Tier Certification is a good indicator of a colocation provider’s attention to due diligence and ensures they’re not cutting corners on maintenance. To find out whether a specific data center – not just the provider – is truly Tier III-certified, visit the Uptime Institute website.  

If you’d like to learn more about the Tier Classification System and what it entails, please view a replay of our recent webinar, “Demystifying Data Center Tier Ratings.” Hosted by Uptime Institute’s senior vice president, Keith Klesner, and Chip Freund, director of colocation product marketing for Cyxtera, it breaks down the intricacies of the Tier System, addresses common shortfalls and challenges some enterprises face with it and answers questions about the time and cost necessary to go through the process.    

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