Recently data centers are being established or expanded according to IT industry development. A data center must be to install emergency generator. In case of the data center located the densely populated urban area, the operating noise of an emergency generator can be the cause of complains. In this case, in order to establish an effective and economical measure and quantitative and thorough review is needed by noise & vibration specialists. To achieve this, in this study, it is suggested noise reduction measure using noise measurement data and 3D noise analysis method.