Most commercial building system designs including controls and building automation are carefully constructed to balance between reliability, performance, efficiency, and budget. On all projects, the need to provide reliability, accuracy, and safety need to be carefully considered as part of the overall design, but when we start looking at critical environments, these requirements become paramount in the design process.
Critical environments refer to the areas or systems that are considered to be mission critical or in other words facilities or areas where losing systems such as lights, power, or HVAC would result in health, safety, or major economic impacts. Some examples of areas often considered as critical can include: data centers (generally Tier 2 or higher), laboratories, critical areas in hospitals (i.e. operating rooms, isolation rooms, labs), call centers, etc.