SOUND INSULATION FOR OFFICES AND DOMESTIC BUILDING WINDOWS.

After reviewing the problem of external noise intrusion into office buildings and homes, the author describes a Swedish development known as the Reventa window. With two panes of 4mm glass and its system of sealing gaskets, this unit provides a laboratory mean reduction value of 38dB (corresponding to a mean reduction in actual use of 35dB - a value acceptable in the majority of noisy air or road traffic environments). The glass spacing of the dual sash linked window amounts to 83mm and ventilation slots between the two sashes eliminates condensation problems. The coupled sashes operated as one opening light but can be safely divided for integral venetian, roller or blackout blind without detriment to the insulation performance. It is pointed out that the sound-insulating advantage of double-glazed windows over a single pane of the same total thickness become appreciable when the distance between the panes is 50mm or more, but that spacings exceeding about 125mm offer practically no further advantage.