There are three levels of Network Equipment – Building System, which offer different levels of assurance:
Level 1: Aimed at office class environments, and is intended to minimize system degradation. Generally, it is used for prototyping and for noncritical systems. This is used when there is a low threshold of risk to equipment and network infrastructure.
Level 2: Rarely referenced middle ground intended for “failure tolerant services.” It is acceptable for data centers that are confident they can offer a controlled environment, but doesn’t pertain to disaster recovery.
Level 3: addresses the needs of critical system environments that need maximum availability. It has strict specifications for fire suppression, thermal margin testing, vibration resistance (earthquakes), airflow patterns, acoustic limits, failover and partial operational requirements (such as chassis fan failures), failure severity levels, RF emissions and tolerances, and testing/certification requirements.