Network Equipment-Building System (NEBS) Compliance refers to the adherence of certain safety, spatial and environmental design guidelines applied to telecom equipment in the United States.

There are three levels of NEBS compliance, which offer different states of assurance:

Level 1: Aimed at office-class environments, and intended to minimize system degradation. Generally, used for prototyping and for noncritical systems. Used when there is a low threshold of risk to equipment and network infrastructure.

Level 2: Intended for “failure-tolerant services.” Level 2 adherence 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 environments that demand maximum availability. This level 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.