Designing Bubbles – Part 2: The Code

Air supported structures, or “bubbles,” are flexible when it comes to purpose and seasonal use. However, unless located on open land, bubbles can be challenging from a code and design perspective. Previously, code regulations for egress and life safety were ambiguous, with jurisdictional interpretation varying by location. The IBC has tried to clarify the regulations for bubbles, with mixed results for urban settings like NYC. The code is clear, imposing strict limitations that seem to make ambitious projects impossible to realize.

While bubbles are typically employed for seasonal protection, having a bubble directly abutting a permanent building, such as a clubhouse, is desirable for projects like Lake Isle. However, locating bubbles adjacent to permanent structures raises several code compliance issues. How does one classify this hybrid building? How can one design the building so that it meets the minimum travel distances and separation from property lines? What are the fire wall requirements for the demising walls? Furthermore, bubbles classified for athletics are limited to 9,500 SF, yet one tennis court alone is 7,200 SF. When facilities require areas greater than those limited by the building code, consulting the local jurisdiction with authority is an absolute requirement.

These are several of the important limitations we kept in mind when considering the use of an air supported structure. Our most recent air supported structure project, Lake Isle Tennis Center in Eastchester, NY, includes three bubbles covering eight tennis courts. The end of the largest bubble wraps around a large viewing window on the second floor of the clubhouse – an atypical condition that allows for spectators in the lounge above to feel close to the action.

For more examples of tennis facilities using air supported structures see the Sportime/John McEnroe Tennis Academy and the Central Park Tennis Center.