BKM provided MEP design services for the 78,000 SF Harford County Fleet Maintenance Facility in Bel Air, MD. The new two-story maintenance facility consists of vehicle maintenance bays, vehicle wash bay, parts storage, fluids storage and distribution, training areas, and administration areas such as offices and conference spaces. The facility was designed to serve Harford County’s vehicle fleet which includes heavy construction equipment, tri-axel dump trucks, tractor trailers, transit buses, first responder vehicles, and pool vehicles. The facility is expected to service over 1,600 vehicles a year in its 38 service bays.
The electrical design included service entrance equipment, power distribution, lighting, fire alarm, lightning protection, and backup generator. Power was distributed through the building via a 480 Volt, 1600 Amp switchboard with automatic throw-over system to switch between the utility source and generator source. The generator source was connected to a 600kW generator to provide backup power for the entire building. Power was distributed to vehicle maintenance equipment such as lift stations, welders, cable reels, and workbenches throughout the vehicle maintenance bays. LED light fixtures were provided for the entire building interior, exterior entrance, and parking lots. Lights were controlled via occupancy sensors, switches, dimming and/or timeclock in accordance with energy code requirements. A combination fire alarm and carbon monoxide detection system was provided to monitor CO levels throughout the vehicle bays.
The mechanical design for the administrative side of the Harford County Fleet Maintenance Facility included four direct expansion (DX), variable air volume rooftop units (RTUs) ranging in size from 5 to 50-tons of cooling. The largest RTU was designed to serve a majority of the office spaces and included variable frequency drives, a total energy recovery wheel, natural gas fired furnace, hot gas reheat for humidity control, and multiple stages of cooling for capacity modulation. The other RTUs serve a training classroom and various parts storage spaces. Variable air volume (VAV) terminal units with electric heating coils were designed for zone temperature control. Heat pump ductless split systems were included to condition the electric room, boiler room, and the occupied area of the checkout bay.
Each of the maintenance wings is ventilated by roof-mounted energy recovery ventilators (ERV). The ERVs were designed to exhaust the maintenance wings in accordance with the International Mechanical Code (IMC) and NFPA 30A. The ERVs range in size from 5,550-12,100 CFM. Heating is provided to the maintenance wings via an in-floor radiant heating systems consisting of multiple zones per wing and multiple circuits per zone. The radiant flooring systems are served by two separate boiler plants consisting of condensing boilers and primary/secondary pumping. The boiler plants range in size from 600-725 MBH. Each maintenance bay is provided with direct source capture vehicle exhaust via hose reels and/or a hose rail system. The hose reels and rails are ducted to roof-mounted central vehicle exhaust fans. All HVAC equipment, sensors, and actuators are BACnet compatible and are integrated into the central building management system.
The plumbing systems in the maintenance wings includes natural gas and domestic water connections to vehicle wash bay equipment, maintenance bay trench drains tied to a 3,000 gallon oil/water separator, compressed air distribution for pneumatic tools and vehicle lifts, and fluid distribution piping serving the completely digital fluids dispensing system. Fluid storage tanks and pumps located in the Fluid Dispensing Room provide various engine oils, transmission fluids, antifreeze, and other fluids to each maintenance wing. In the 2-story administrative core of the building, the domestic water and sanitary systems serve multiple public and private toilet rooms, showers, utility/mop sinks, dish washers, break room sinks, and washing machines. The building is served by an 8-inch combined domestic water/fire protection water service. Modular domestic water booster pumps are used to ensure the building has adequate domestic water pressure to serve all of the plumbing fixtures within the building. The natural gas system serves the building domestic water heaters as well as mechanical equipment (boilers, RTUs, and ERVs).
