Performance of sealed double-glazing units.

Discusses the problems of sealing double glazing to reduce condensation between the panes. Describes sealed glazing unit and sealants used. Discusses causes of failures. Reports tests for seal leakage made by lowering air pressure surrounding theunit and observing glass deflection. Windows were also tested by weathering in the laboratory and by exposure to actual weather conditions. Discusses results and finds extreme difficulty in providing and maintaining an effective sealing system. Calculations indicate that units with imperfect seals may perform satisfactorily in the field for several years, particularly if desiccant is employed to dry the air space.