Civic Center at Veteran’s Plaza

Plumbing, Heating, Ventilating and Air Conditioning System

The Civic Center at Veteran’s Plaza project involved construction of a 45,000 sq. ft. full fit-out of an exhibition space, meeting rooms, office and general use building including an outdoor skating rink. Mechanical Engineering & Construction Corporation (MEC²) was the mechanical contractor responsible for the plumbing and heating, ventilating, air conditioning, and control system installation. The project was a new facility with air-cooled chillers, gas-fired hot-water boilers, mechanical pumping systems, dedicated outdoor air systems, IT and Data Server Rooms, natural gas for an emergency generator for the building, a serving kitchen, and variable air volume roof top and indoor air-handling units. The facility is a new 3-story structure located in the town center area of Silver Spring, Maryland.

Construction was an intense coordination process with Montgomery County, Costello Construction, and the sub-contractors to build a state-of-the-art Civic Center building that maintained site cleanliness, safety and environmentally-friendly impacts to the existing area.

The HVAC system serving the Civic Center provides year-round temperature and ventilation that meets or exceeds all applicable code and industry standards as defined by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE). The system utilizes a 190 ton high-efficient air-cooled chiller, pumping chilled water to variable volume rooftop units, indoor air handlers, and a dedicated outdoor air system that distributes supply air to fan-powered variable air volume terminals. The air handling units incorporate economizer cycles which constantly supply filtered air. Heating is supplied by two (2) 1.4 million BTU high-efficient condensing type hot-water boilers housed in the boiler/pump room. The overall heating, ventilating and air conditioning system serving the building is monitored and controlled by a direct digital computer-based control system. The control system automatically coordinates the function of all mechanical components to assure economical and reliable operation. The system may be monitored within the building and remotely for failures of equipment or operating criteria outside of pre-set levels.

The scope of the project consisted of providing heating, ventilating, and air conditioning for the new facility. The ventilation system and air conditioning system is provided by rooftop and indoor variable air volume rooftop units provided with supply and relief fans, variable frequency drives and air-cooled chiller refrigeration systems consisting of high efficient compressors, condenser coils and fans. As well as selecting high efficient cooling systems and energy-saving variable frequency drives, the air handling units are equipped with free cooling cycles and carbon dioxide monitoring to ensure acceptable indoor air quality levels. High efficient filtration is installed in the rooftop units to remove airborne contaminants. The supply air is distributed through insulated sheet metal ductwork to variable air volume terminal units.

The heating system for the building is designed to provide heating water to the terminal units for the supply of warm air to the spaces. The terminal units are equipped with heating coils so we can maximize the heat output of the units while minimizing the demand for heating water quantities. The heating water is generated by two high-efficient condensing type boilers. The boiler system utilizes reset water temperature schedules to increase the system’s efficiency. The boilers can fully modulate the entire range of the heating demand spectrum and these boilers are coupled with base-mounted pumps designed to adequately handle the heating demand from the building.

The building automatic temperature control system by Siemens monitors and controls every HVAC component in the building and also controls the building lighting system scheduling. The rooftop units and terminal units work in sequence to minimize energy usage while providing the required air conditioning capacity. The control system is married to the boiler control system to integrate the heating process efficiently and effectively. Innovative control strategies for static air pressure recalculation were implemented for the control of the variable frequency drives to minimize fan power usage and save energy use and costs.

The IT and Server rooms were provided with Liebert computer room air conditioning units. The units are refrigerant based. This installation minimized overhead water piping in the data rooms.

The emergency generator at the facility required natural gas piping to be extended from the building system to the location outdoors on grade. Challenges to this $2.6 million mechanical undertaking included a coordination process that involved MEC² redrawing and providing appropriate layout for the entire mechanical system. During the initial stages of construction coordination, MEC² realized there was inadequate ceiling space to provide for the construction as planned. By incorporating 3-D building modeling, conflicts with all trades were identified, communicated, and action plans were incorporated. Electrical subcontractors, fire protection subcontractors, and the general contractor coordinated all aspects of the building based on the mechanical 3-D model and the resulting coordinated drawings.

Although this building was built to LEED® requirements, Montgomery County will not have the building certified. These requirements added additional tasks to the construction process including storage of materials off of direct contact with the floor, temporary capping of ductwork and terminal units to minimize debris entrainment, providing required filtration over the return openings, and specific leakage testing of our systems. Close coordination with the Commissioning Agent and all trades was critical to minimize dust and debris in construction practices. As well, this project was completed on time and within budget.

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