Meadowridge 95: LEED® Core & Shell/Pre-certified Silver

Heating, Ventilating and Air Conditioning System

The Meadowridge 95 Building II project involved construction of a 60,000 sq. ft. shell office structure which will be LEED® certified for Core and Shell. Mechanical Engineering & Construction Corporation (MEC²) was the mechanical contractor responsible for the heating, ventilating, air conditioning, and control system installation.

Construction was an intense coordination process with the Owner, Merritt Properties LLC, the commissioning agent, and the sub-contractors to build a state-of-the-art office building that maintained site cleanliness, safety and environmentally friendly impacts to the existing area.

The HVAC system serving Meadowridge 95 Building II 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 is a prototype of office buildings to come, utilizing an under-floor air distribution system supplied by air column units coupled with VAV rooftop air conditioning units equipped with evaporative condensing and economizer cycles which constantly supply filtered air. Heating is supplied by high-efficient, hot water boilers housed in a boiler/pump package mounted on the roof.

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.

Challenges to this $1.25 million mechanical undertaking included the operation of the two rooftop units which are headered together creating redundancy in the building supply system but also as a shell building, we needed to provide the ability to operate the building on one unit when the load dictates. Creative control scenarios with static pressure sensors and isolation dampers gave a successful result.

Since the building is a shell, flexibility to future tenants needs is of paramount importance, but the building owner wanted a consistent feel to the building; therefore selecting products required viewing samples. For example, different types of under-floor supply diffusers were installed as a mock-up to determine which type had the desired look and ease of operation.

LEED® requirements added additional tasks to the construction process that included keeping stored materials from making 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. A two-week building purge was a last minute addition to the schedule.

Close coordination with all trades was critical to minimize dust and debris in construction practices, reviewing the building construction to verify acceptable sealing of windows and walls, and proper installation of building insulation. We observed the construction of the raised floor system to verify sealing of panels and continuity and cleanliness of the under-floor supply air plenum.

As future tenant improvements occur, special attention must be given to maintaining a clean environment inside the building. Building in an occupied building has its challenges. Airtight partitions and filtration units which can pressurize specific sections of the building will be required. Advanced planning is currently underway.

This project finished on time and within budget.

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