Transforming Modern Workspaces
Architect William McDonough finds amusement in the disconnection of many modern buildings from the natural world. According to an article in “Architecture Week,” when confronted with the Wall Street Journal article “Windows That Open Are the Latest Office Amenity,” McDonough responded with a mixture of disbelief and disappointment, saying he questions the state of society where something as basic as fresh air in the workplace is considered newsworthy.
McDonough’s philosophy of reconnecting with the outdoors heavily influenced his design choices for the environmentally conscious and highly efficient building at 901 Cherry Ave. in San Bruno, Ca. Originally serving as the corporate headquarters for Gap, Inc., the building gained recognition in the realm of sustainable construction and received accolades such as the Savings by Design Award and the Business Week Architectural Award.
While most people are familiar with its visually stunning undulating roof adorned with native perennials and grasses, the building’s energy efficiency is largely attributed to its Under Floor Air Distribution System (UFAD), a somewhat unsung hero in reducing cooling costs.
The UFAD System and Its Benefits
The UFAD system is comprised of an under-floor space that includes a substantial concrete slab, offering numerous advantages including improved ventilation, convenient infrastructure (such as wiring systems running beneath the floor for better access to electrical components and easier cable management), and reduced cooling expenses.
At 901 Cherry, the system is designed to decrease electricity usage by avoiding mechanical cooling during peak hours.
Given San Bruno’s mild climate, with summer nighttime temperatures averaging between 55 and 65 degrees, the concrete slab can be effectively cooled during the night. From midnight to 8 a.m., when electrical costs are at their lowest, the mechanical ventilation system introduces cool air into the under-floor space.
This cool air is stored within the concrete. As temperatures rise during the day, a natural convection effect occurs, wherein air from both the HVAC system and windows is drawn in at a lower level and expelled at a higher level, reducing conflicts between the two systems.
By directing incoming heat over the UFAD slab, the building effectively functions as a large cooling device. The warm air gradually ascends along the building’s perimeter and is exhausted at the roof level.
Apart from reducing off-peak energy loads (resulting in estimated annual savings of 30% according to occupants), the system incorporates several features that enhance employee productivity and satisfaction, such as operable windows, natural airflow, and abundant natural daylight.
Furthermore, no workspace is located more than 25 feet away from an outside view.
Originally occupied by Gap Inc., 901 Cherry Avenue is now headquarters for YouTube. The online giant has adapted the green building to suit the needs and tastes of its millennial workers, adding a putting green, lap pool, and charismatic garden gnome.
Although these features may not directly contribute to the building’s environmental credentials (except for the putting green), they not only further boost employee happiness, but also add a touch of cultural flair to the intersection of contemporary art and the science of green building.