In the home of the very small, a massive effort to cool, clean and isolate

Stundtner

By Robert Stundtner, Duffield Project Director

Duffield Hall looks like it has been precision sculpted from metal and glass -- not unlike the nanofabrication processes that take place inside -- except the scale is at the very large instead of the very small.

How large? Duffield contains 7,600 cubic yards of concrete and 1,000 tons of reinforcing and structural steel.

What really distinguishes science and engineering facilities, such as Duffield, are the size and capacities of the mechanical (principally ventilation), electrical and plumbing systems required for safe and efficient operation of research laboratories. About half of the construction cost of a modern research facility goes into these systems. The size of the mechanical equipment, in particular, increases the space required.

A great deal of air must be passed through these facilities to reduce chemical exposures or remove heat from the research equipment. The air handlers that supply the conditioned air are typically the size of large tractor trailers, and Duffield has two -- one in the basement mechanical room for the clean room and one in the fourth-floor penthouse for the laboratories on the second and third floors. Together they provide almost 140,000 cubic feet per minute of heated or cooled air. Five smaller air handlers provide ventilation for offices, the atriums, support spaces and mechanical rooms.

Long ducts, high ceilings

Making things at the atomic scale requires very clean conditions so particles in the air don't contaminate the work. Most of the first floor of Duffield is a very specialized laboratory called a clean room. You probably have noticed the particles of dust dancing in a shaft of sunlight streaming through a window. Hundreds of thousands, even millions of particles in every cubic meter of air would not be unusual because many are too small to see. Clean rooms are classified by the number of particles of a particular size (generally not even visible to the naked eye) per cubic meter. Duffield's clean room stays clean by recirculating the air through special HEPA (high efficiency particulate air) filters 120 times per hour. Half of the ceiling in the clean room is occupied by HEPA filters.

Left to run at full ventilation capacity, Duffield would represent up to 5 percent of the total energy consumed on campus. In laboratories on the second and third floors, room occupancy sensors and fume hood sash controllers adjust airflow to meet the needs for safe levels of ventilation. In the clean room, recirculation rates adjust to the minimum level necessary to maintain cleanliness and extremely accurate room temperature control. In combination, these energy conservation measures reduce the potential usage by 25 to 30 percent.

Giving no vibration

These unusually demanding criteria were achieved by creating slabs that are placed directly on the earth and isolated from the rest of the building. They are at the southern end of Duffield, away from the vibration-inducing traffic on Campus Road.

The lab suites requiring the lowest vibration performance also require the lowest possible level of EMF. Because of this, the electrical distribution system for Duffield, with its strong EMF, is located at the north end of the building, as far as possible from the lab suites, with their sensitive equipment. As a result these labs have much lower levels of unwanted EMF than comparable facilities, thanks to isolation transformers, careful attention to electrical wiring and insulation of floors, walls and ceilings from the rest of the structure.