One pane is referred to as a single glaze, two panes of glass with an air gap is referred to a dual glaze. A dual glaze should be used for larger size openings and/or if equipment is expected to be constantly on or loud. We have standardized on using two glass thicknesses in dual glaze frames – a 6mm & a 10mm - to stop noise on different frequencies and achieve a higher STC rating (dual glaze 6mm & 10mm have 40+STC). If a dual glaze is required; it is recommended to purchase a fully fabricated frame to ensure the sealed air gap in the middle is as clean as possible prior to sealing. It can be difficult to achieve this when installing a dual glaze setup on site or without proper experience. A single pane setup would be recommended when installing yourself.