GES provided MEP & FP engineering design, as well as commissioning services, for the renovation of a deteriorated vivarium and laboratory into an ABSL-2 small animal vivarium. The existing laboratory, was conditioned via a water source heat pump system with the fluid cooler located on grade, and two adjacent rooms were served by a dedicated split DX heat pump system. Due to the space constraints, the factory fabricated packaged rooftop unit (RTU) was designed to be located on grade with two exhaust fans and electric duct heaters. The RTU was designed with one bank of 30% efficient (MERV 8) pre-filters, one bank of 90% efficient (MERV 13) final-filters, and one bank of 95% efficient (MERV 14) final-filters. Operating rooms for animal surgery are HEPA filtered in accordance with DRM requirements. The DX RTU is equipped with electric heat and electric steam humidifier, 100% OA type, variable air volume, low pressure distribution equipped with VFDs. The exhaust system utilizes two 3,300 cfm manifolded high plume exhaust fans.