Critical facilities may include, but aren’t limited to, hospitals, health care centers, nursing homes, schools, police stations, and fire and emergency response installations as well as installations that produce, use, or store hazardous materials or hazardous waste. We could go a step further and define them as facilities that are critical to the health and welfare of the population and those that are especially important following a natural disaster or another disruptive occurrence. Critical facilities are vital because they provide essential services and protect lives and property. A loss of one of these critical facilities would result in severe economic and catastrophic impact.
Another layer of critical facilities are mission critical facilities. These facilities are broadly defined as containing operation that, if interrupted, will negatively impact business activities ranging from loss of revenue to jeopardizing legal conformity to, in extreme cases, loss of life. Some of the facilities that meet these criteria are hospitals, laboratories, data centers, public safety centers, and military installations. There is no uniform definition of mission critical, but, essentially, these facilities must maintain continuous operation. This means redundant cooling systems and power must be available at varying degrees of reliability. For power reliability, the National Fire Protection Association (NFPA) 70: National Electric Code, Facility Guidelines Institute (FGI) Guidelines, ASHRAE standards, and presidential directives offers some guidelines, but the design for reliability depends on the owners' and design engineers’ interpretation of which systems are mission critical and which are not.