Data center tier classifications

Both ANSI (ANSI TIA-942 Standard) and the Uptime Institute have established tier classifications as guidelines for designing topologies that deliver data center availability and reliability. These resources further explain the differences between types of mission critical facilities. The following list explains the tier classifications:

Tier 1: Basic

• Susceptible to disruptions from planned and unplanned activity
• Capacity design is need (N) with no redundant components
• Infrastructure shutdown required for preventive maintenance and repair work.

Tier 2: Redundant components

• Less susceptible to disruptions from planned and unplanned activity
• Capacity design is N with some redundant components
• Single threaded distribution path
• Infrastructure shutdown required for preventive maintenance and repair work.

Tier 3: Concurrent maintenance

• Allows for planned infrastructure activity (maintenance, repair, expansion) without disruption
• Capacity design is N+1
• Dual threaded distribution path
• Errors in operation or failures can still cause a disruption.

Tier 4: Fault tolerant

• High reliability, availability, and serviceability
• Allows for planned infrastructure activity (maintenance, repair, expansion) without disruption
• Capacity design is system + system (2N)
• Dual threaded distribution path
• System can sustain one unplanned failure with no impact to critical load.

Kenneth Kutsmeda is an engineering design principal at Jacobs Engineering in Philadelphia. For more than 18 years, he has been responsible for engineering, designing, and commissioning power distribution systems for mission critical facilities. His project experience includes data centers, specialized research and development buildings, and large-scale technology facilities containing medium-voltage distribution.

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our WTWH Media editorial team and getting the recognition you and your company deserve. Click here to start this process.