This renovated warehouse uses an under-the-floor air distribution system.
A nationally-known advertising agency has found a new home in a former warehouse in Portland, Ore. Novel architectural elements have been used to form an office environment that encourages communication and creativity - essential ingredients in the advertising business. The comfort system that supports that environment is equally creative and also relies on communications.

Wieden + Kennedy is an international agency known for its unique consumer product advertising. With clients that have included Nike, Coca-Cola and Microsoft, the company has produced award-winning campaigns that are especially focused on younger buyers. Until recently, the firm's Portland headquarters was housed in three different leased spaces. In 1997, the firm decided to consolidate its operations into a single, larger facility.

The agency had indicated an interest in a "loft style" building with the potential for abundant communication among project teams. The ultimate decision was to remodel an old warehouse building in Portland's revitalized, post-industrial neighborhood known as the Pearl District. The structure was built in 1913 as a dry-goods warehouse. In fact, the building was originally occupied by the Fuller Brush Company. It served in this capacity until 1946, when it was remodeled to function as a cold storage warehouse. It was used for this purpose until a few months before it was acquired for renovation in 1996. The building had deteriorated and was a surprising choice for conversion to an advertising agency headquarters.

The building had potential, but a lot of problems as well. The building's foundations had settled in some places. Consequently, the interior floors were uneven and major structural reinforcement for the building was necessary.

The primary comfort system for most of the office spaces in the building features six self-contained air conditioning units rated at 30 tons each. These Trane Signature series units, Model SCWF, are located in space-saving mechanical rooms placed throughout the building.

The most unusual aspect of the hvac design is the conditioned air distribution system. The Wieden + Kennedy building features a low-pressure under-floor system. According to Dennis Wilde, Gerding/Edlen Development Co., this choice grew out of the necessity to install raised floors over the uneven original flooring throughout the upper stories. The cavity below the raised "computer flooring" created a space to run cabling and conduit. Access to the under-floor area can be achieved by simply lifting up one of the 2X2 ft. floor sections.

The raised flooring design also created a void to serve as an air distribution plenum. Conditioned air flows to occupied spaces through floor diffusers that can be adjusted to meet local needs and preferences. System operating pressures are typically about 0.1 in. H2O. Conditioned air is delivered at temperatures of around 658F. Because the entire subfloor area serves as a distribution plenum, space conditioning is also accomplished with direct radiation through the floor panels.

To meet the need for building heat, perimeter zones on each floor are served by separate single-duct VAV systems supplied by the self-contained units. These zones are baffled off from the balance of the floor areas. The VAV units that serve these areas are equipped with hot water reheat coils.

Each self-contained hvac unit serves a specific two-floor section of the building. "This under-floor approach," according to Wilde, "has several advantages. Air handling energy is less, control is simplified, and fewer zones are needed. The amount of sheet metal required is much less."

Individual occupants are encouraged to adjust the floor diffusers to meet individual preferences. And as the floor plan is changed, the diffusers can simply be relocated to a different location on the continuous under-floor plenum.