Understanding the Data Center Tiers

Data center tiers is a term that you are likely to encounter a lot if you are in the market for collocation services and other IT infrastructure related services.  Data center managers or sales people will always be talking about their “tiers”. But what exactly do the tier numbers mean to the end users. What does it mean when a facility talks about its tier 1, tier 2, tier 3 or tier 4 data center?

data center tiers

Defining Data Center Tiers

The tier number designations are usually important when it comes to the design or upgrade of data centers. These numbers are used in the classification of data center facilities based on certain standards. The criteria for this classification will vary based on organizational setting. This data center information is used in the objectification of the data center infrastructure features such as the type of the infrastructure, the functionalities, the capacities as well as the facility’s operational sustainability.

When it comes to the data center tiers, there are certain systems that you are likely to encounter. These include the following:

  • The Uptime Institute
  • The Telecommunications Industry Association

The Uptime Institute

The Uptime Institute created a data centre tier standard which is one of the most widely recognized and widely referenced. This standard was created in 1995 before being revised in 2013. It offers a basis on which a comparison on the uptime can be made on various data centers.

The Uptime Institute standard is a proprietary system that will certify a data center for a fee on whether it has met the criteria for any of the four tiers which are generally denoted using the Roman numerals. The other systems for certifications generally use the Arabic numerals. The Tier I in the Uptime Institute standard offers a single and non-redundant distribution path while the Tier IV is a fully fault-tolerant data center facility with a 2N redundant power as well as cooling amongst other premium features. However, the evaluation criteria for the Uptime Institute is not generally published for end users. With the revisions made in 2013, the Uptime Institute has now introduced new ratings such as Gold, Silver and Bronze. These have been intertwined with the 4-tier system of the datacenter standards.


This is the standard for the Telecommunication Industry Association. The TIA-942 datacenter solutions will specify the standards used for cabling systems as well as network design. These standards have been well defined and also cater for the physical construction, the electrical power, redundancy, commissioning and monitoring security amongst others.

Both the Uptime Institute and the TIA standards share many similar features such as the N+0-no redundancy, single path for power as well as cooling distribution, etc for tier 1. Before building your data centers, it is important to get the designs certified for a certain Uptime Institute tier. It is also important to follow through with the design specs during the construction of the data center. It is also important to ensure that operational sustainability standards are maintained during the operation of the center. The Data Center Journal covers up to date information on the developments and trends in the data center design.

Check out Data Center Journal or the company’s website for additional resources http://www.datacenterjournal.com/designing-multitier-data-center/.