Are two skins better than one?
A couple of articles I worked on recently for this publication and for its sister publication, Healthcare Building Ideas, raised a question for me: What do American hospitals have against operable windows?
One of the articles in HEALTHCARE DESIGN's August Showcase (“Full-Service Lifecare”) discussed the operable windows of San Francisco's Laguna Honda Hospital and recounted the initial discomfort experienced by one of the administrators, a veteran healthcare building engineer, who concluded that San Francisco's mild climate trumped his concerns regarding the idea. The other article, published in the “Build It Right” department of the Summer 2010 edition of Healthcare Building Ideas, took me a step further toward the intriguing technology of the double-skinned façade. Architects Angela E. Watson and David Meeks of Shepley Bulfinch extolled the energy-saving virtues of the “European style” of building, with air-handling dependent upon the natural convection effects produced by double-skinned facades, with reduced HVAC requirements and operable windows.
The double-skinned façade strikes me as an engineering marvel, with its complicated array and tremendous coordination of various openings, louvers, sunshades, chilled beam ceilings, heat pumps, and the like. From this arise claims of major reductions in energy use for heating and cooling and enhanced morale for building occupants from having greater control of their immediate surroundings. I do understand, however, why the concept has yet to catch on in the United States, even though the double-skin concept goes back to the days of LeCorbusier and Alvar Aalto, and its use in commercial office buildings and hospitals is not at all uncommon in Europe. In short, double-skinned façades have yet to make the economic case for themselves in this country.
No question, the space requirements and concomitant loss of usable floor space demanded by a second skin are costly, as are the increased use of high-tech glass for both skins and the additional maintenance/cleaning involved. Let's face it, when it comes to energy conservation, our energy isn't nearly as expensive as European energy. This has enabled us to get by with relying on totally conditioned air within a sealed environment-not necessarily a bad thing for healthcare.
But I wonder, when our energy expenses continue to grow, when problems of access and international competition drive oil prices ever higher, and as the realization dawns that we in the United States pay for oil not only with money, but with the blood of our armed forces in Middle East wars, how will the double-skin façade look then?
I have to believe that there is plenty of data available these days on the energy-saving payoffs of this approach, as experienced in Europe. It might do well for the architecture/engineering/construction fields in our country to start paying serious attention.
Healthcare Design 2010 December;10(12):56