Demystifying window and door selection for single-family homes in high-wind environments

The failure of the building envelope, including windows, doors and roof cov erings, leads to a major portion of the damage of single-family homes wroug ht by hurricanes. Failure of the building envelope allows wind and water in trusion into the building, and pressurization or depressurization of the in terior of a structure may significantly increase differential pressure load s on the structure itself. Damage to windows and doors can result fi om imp act by wind-borne missiles or from the pressure capacity of the unit being exceeded. Commonly available window units may be performance rated (includi ng consideration of air and water intrusion at modest pressures, as well as maximum allowable differential pressure), but there is no readily availabl e means for a house designer, contractor or owner to determine the appropri ate rating for a desired window installation (wind-speed claims, while bein g the simplest to use, are probably the least definable and are the most su bject to abuse). Under current design algorithms, the design pressure on wi ndows and doors requires an analysis of each unit based on the dimensions o f the unit, the dimensions of the structure, the location of the unit withi n the structure, and assumptions concerning internal pressurization. This p aper reports a design rationale developed under the Blue Sky program for th e required pressure capacity of windows that proposes both a window selecti on tool and a design guide for reducing window pressures (the information i s also useful for shutter design and/or selection). The calculated design p ressures suggest that most of the windows installed land being installed) i n the 110 mph (fastest mile) zone probably are not rated for the design pre ssure. (a 1998 Elsevier Science Ltd. All rights reserved.