Cleary Zimmermann Engineers provided MEP design for the major design/build renovation of San Antonio's historic City Hall. Constructed in 1889, the complete gut of the 46,578 SF building brought City Hall into compliance with newest building codes. The program included offices for the City of San Antonio's leadership, including the Mayor, City Manager, City Council, City Attorney, and their associated staff. It also included a media room, conference spaces of various sizes, a gallery, visitor screening area, breakroom/catering area, and restrooms. This project is seeking LEED Silver Certification.
The scope included the complete demolition of the existing HVAC systems. The new HVAC was comprised of VRF systems utilizing combination of ducted cassette and wall mounted units. A dedicated outside air system was designed to provide adequate ventilation and humidity control throughout the building. A large portion of the building had hard ceilings, and as such, coordination for access was paramount and refrigerant monitoring was added to provide a level of protection for trouble shooting potential leaks within the system. Due to the historic nature of the building, ceiling space was limited and ductwork coordination with other disciplines was crucial. We also provided full DDC controls.
Electrical service design included replacing the existing 30+-year old 208Y/120V, 3 phase, 4 wire, 1200 amp service lateral with a new service lateral of the same size from the existing Power Company underground vault to the main switchboard located in the lower level of the building. Other than the reused main switchboard, all other existing conduit, wiring, and panelboards were replaced. A standard radial distribution was used. Lightning protection was provided to the building for the first time to protect the historical structure and better protect electronic components. In order to minimize damage to existing historic masonry walls, indoor power design included direction to Contractor to have selected device rough-ins served from above and other rough-ins served from below. New period-appropriate LED lighting selected by Architect was used throughout the building. Our team specified specific drivers for desired lighting levels and lighting controls in order comply with 2010 ASHRAE and LEED Silver requirements. All lighting was controlled by occupancy sensors. Photocells for daylight harvesting were provided where required by ASHRAE and LEED.
Plumbing systems consisted of domestic cold water, domestic hot water, sanitary sewer, vent, and storm drains. Hot water was provided throughout the building to fixtures utilizing a solar powered hot water heater with heat exchanger panels located on the roof. Fixtures were selected to help achieve maximum LEED goals.