Develop a demolition and new mechanical, HVAC, plan that serves holding cells, central station, interview rooms, control room and photo/fingerprint room with a total of 8,000 sq. ft. area. Design a new ductwork system for existing, relatively new, A/C units. Connect a portion of existing return ductwork to new ductwork system. Remove the rest of existing return duct and cap return air opening at the unit to provide a 100% outside air system. Interlock exhaust fans with A/C unit that serves the holding cells and central station area. Provide temperature sensor on one of the exhaust ducts with control thermostat located in central station area. Provide new smoke detectors on supply ducts downstream of existing A/C unit supply air openings. This project was designed in metric unit system.