Double glazing, used in the sidelites of buses, is produced by fusing two pieces of tempered glass in a second process with a cavity of 6-12 mm between them. This technique provides effective heat and sound insulation in vehicles with large glass surfaces, such as buses.
Double glazing is used on the sidelites of Heavy Commercial Vehicles.
An air cavity is created by placing an aluminum spacer between the two glass panes. The cavity is commonly 9-12 mm. In some projects, the cavity can also be 6 mm. The greater the cavity distance, the better the sound and heat insulation performance. Desiccants are used inside the spacers. An aluminum spacer is joined to the glass with butyl. Thiokol (polysulfide) is applied to the edges of the glass to provide the final insulation.