Interstitial space (architecture)

An interstitial space is an intermediate space located between regular-use floors, commonly located in hospitals and laboratory-type buildings to allow space for the mechanical systems of the building. By providing this space, laboratory and hospital rooms may be easily rearranged throughout their lifecycles and therefore reduce lifecycle cost.

An interstitial space is useful when the mechanical system of the building is highly sophisticated and changing the space on the primary floors is a distinct possibility. The heights of these spaces are generally six to eight feet and allow easy access for repair or alteration. If changes or maintenance need to be performed in the interstitial space, the primary space does not need to be shut down, which is important in buildings like hospitals where the equipment in the space must operate constantly. Unlike traditionally built buildings, where the mechanical space is located in the basement or on the top floor, the interstitial space needs few vertical penetrations and therefore leaves more open space on the primary floor. The entire floor plan of these buildings can be more open because there are fewer fixed vertical penetrations through the floor and walls.

Another way to use an interstitial space is to incorporate a design that divides the functions of the building into groups and localizes them. The Zeidler Partnership Architects’ (ZPA) design of the William Osler Health Centre (WOHC) in Brampton, Ontario, is one example of this design. (Note: this was designed but ZPA was not awarded the project.) The groups in this design are based on similar structural and mechanical systems. Flexible design allows for easy expansion or redesign in the future. Horizontal expansion is especially easy because of the interstitial space between the surgical suite and the emergency floors, where the mechanical system functions are the most crucial in this building. Double floor height is used to maintain the horizontal flow of connections throughout the rest of the building without causing any interference with other building systems.

The idea of using an interstitial space was started in the 1960s by professors at Texas A&M University’s College of Architecture. Their concept was to standardize spaces and allow for rapid changes in medical facilities. While the spaces for building systems like plumbing, mechanical, and electrical systems were not as large as today’s, it was an important beginning of an idea to separate the systems by floor. The first building to actually use an interstitial space design was Louis Kahn’s Salk Institute of Biological Studies in La Jolla, California. The design allowed the building to keep up with ever-changing technology. From there, designs progressed to concepts created by ZPA; a firm who has completed over 40 healthcare and lab facilities for buildings using an interstitial space design. Today, many firms have drawn inspiration from ZPA and use their concept to develop their own design. Some designs cover the whole floor area and some, like the WOHC, are partial interstitial spaces.

...
Wikipedia