When it comes to classifying Data Centers, the terms Rated and Tier are fundamental, yet their differences are not always clear. Both systems offer standards that help evaluate the quality and reliability of a data center, though from different approaches. 

The Tier system, developed by the Uptime Institute, focuses on infrastructure and design redundancy, classifying Data Centers into four levels based on their ability to withstand failures and ensure availability. If you're interested in learning more about the U.S. sustainability regulations, check out the ebook we created with Uptime Institute

On the other hand, the Rated system, based on the TIA-942 standard, goes beyond design, emphasizing operational quality and compliance with international standards, evaluating aspects such as security, connectivity, and efficiency. 

Tier: The Design and Redundancy Standard 

The Tier system, developed by the Uptime Institute, classifies Data Centers into four levels (Tier I to IV) based on their infrastructure and fault-tolerance capacity. 

What does the Tier system evaluate? 

• Redundancy: The more redundant components (power, cooling, etc.), the higher the reliability. 
• Paths and Electrical Systems: The number of independent power and cooling distribution paths is assessed. Higher levels feature multiple paths, ensuring greater stability during failures. 
• Concurrent maintainability: Higher levels allow maintenance without interrupting operations 
• Fault tolerance: Measures the center's ability to withstand failures.

What characterizes each Tier level? 

• Tier I: Basic, with a single path for power and cooling distribution. Ideal for small businesses with low tolerance for downtime. 
• Tier II: Adds partial redundancy in power and cooling. 
• Tier III: Enables maintenance without interruptions thanks to redundant paths 
• Tier IV: Maximum availability, designed to withstand failures of any component.

The objective of Tiers is to ensure the design meets the required availability levels for critical operations.

 Rated: Beyond Design, Towards Operational Quality 

The Rated concept stems from the TIA-942 standard (Telecommunications Infrastructure Standard for Data Centers), evaluating broader aspects than just the physical design of the Data Center. While Tier systems focus on redundancy and availability, Rated addresses other factors impacting real performance and operational reliability.. 

What does the Rated system evaluate? 

The TIA-942 standard classifies Data Centers into four levels (Rated 1 to Rated 4) based on their capacity to withstand failures and deliver quality in key areas: 

• Infrastructure: Includes elements such as network design, power, and cooling systems. 
• Connectivity: Assesses available bandwidth and redundancy in connections to ensure high data availability. 
• Physical and logical security: Measures protection against unauthorized access in both physical and technological environments. 
• International standards: Ensures compliance with global standards for sustainability, efficiency, and security.. 

What characterizes each Rated level? 

Rated 1: Basic infrastructure with low fault tolerance.

Rated 2: Partial redundancy in power and cooling, offering higher reliability. 

Rated 3: Fault-tolerant systems capable of maintenance without interrupting operations. 

Rated 4: Maximum robustness, total fault tolerance, and nearly continuous availability (99.995%). 

Having a Tier or Rated system in a Data Center is key to ensuring high availability, reliability, and security. These systems guarantee that the Data Center can withstand failures without service interruptions, protect against financial losses due to downtime, comply with security and privacy regulations, and enhance operational and energy efficiency. Additionally, they facilitate scalability, allowing the Data Center to adapt to future needs without compromising performance..