The entire Building Automation System (BAS) serving the IBM - Hazelwood Data Center was replaced and upgraded to provide reliable control of mechanical and electrical data center systems. The primary commissioning goal was to demonstrate reliability and identify potential single points of failure for elimination. The BAS consists of over 14,000 points of integrated monitoring and control systems including space temperature and humidity control, central cooling and heating plant operations, power monitoring, emergency power, fire alarm, lighting control etc. All commissioning tests were executed in a live data center without causing disruption of operations.