Critical facilities such as data centers use a wide range of mechanical-electrical support systems that are essential to their day-to-day operations. These support systems are very sensitive resources which upon failure would cause loss of data and pose a possible threat to the environment. Protecting these resources from predictable, as well as unpredictable conditions or abnormal situations requires advanced environmental monitoring and control. In addition to standard lighting, heating, cooling and ventilating systems, energy that is used in critical facilities require different approaches and strategies to reduce energy consumption. In Data Centers, energy use accounts for a significant and increasing portion of operating costs. Managing energy consumption without compromising reliability or environmental requirements presents a challenge. The challenge in cutting costs lies in improving equipment performance while reducing energy consumption without diminishing the comfort, safety or security of this environment.