The Resonance team was retained to assist with the master planning and entitlement process for the expansion of Digital Realty’s 360 Spear Street Data Center. The Data Center is located in downtown San Francisco, next to residences and other businesses. We performed measurements of the ambient noise environment and calculated the noise from emergency generators, HVAC equipment, and other project mechanical equipment. A three-dimensional noise model was used to perform the calculations so that site-specific conditions such as reflected noise from the adjacent buildings could be analyzed.