
TIER classification for data centers:
availability and security
Details of the standard
The TIER classification is an internationally recognized standard for specifying
the availability of data centers. It defines requirements for building structures,
operational facilities and systems in the areas of technical fire protection, power
supply and cooling supply.
The aim is to create a clear classification into four TIER levels that evaluate
the reliability and redundancy of a data center.
TIER levels at a glance
- TIER 1: Simple data center without redundancy. Designed for low requirements,
with an availability of around 99.67%. - TIER 2: Data center with redundant components (N+1). Higher reliability and
an availability of around 99.75%. - TIER 3: Data center with multiple redundant power and cooling supply.
Maintenance work can be carried out without interrupting operations.
Availability of around 99.98%. - TIER 4: Highest availability class with fully redundant and fault-tolerant
systems (2N+1). No downtime due to maintenance or component failures,
with an availability of 99.99 %.
Key aspects of the TIER classification
- Building structures: Requirements for physical safety, such as robust
building structures and fire protection measures. - Technical fire protection: Systems such as smoke extraction systems,
gas extinguishing systems and monitoring systems ensure effective protection. - Power supply: Redundant UPS systems, diesel generators and independent
power paths ensure an uninterrupted supply. - Cooling supply: Redundant air conditioning systems ensure reliable
cooling of IT hardware, even in the event of failures.
Advantages of the TIER classification
- Availability: Clear classification enables targeted planning of fail-safety
according to the company's requirements. - Safety: Compliance with strict fire protection and energy supply standards
minimizes risks. - Competitive advantage: Higher TIER levels signal maximum reliability
and safety to customers and partners.
The TIER classification helps companies to choose the right standard for their
IT infrastructure and ensures that data centers are optimally designed to meet
specific requirements in terms of availability and security.



