When using laminated glass, is 6 + 6 mm laminate preferable to four layers of 3 mm glass?
The advantage of laminated glass is largely due to the energy losses in the layers binding the glass together. How much the transmission loss is improved depends not just on the number of layers, but also on their characteristics.With suitable interlayers, the number of layers should not be significant. • For windows with double glazing, what are the benefits of using two different thicknesses of glass, or slanting the glass on one side so the airspace is not uniform? Slanting the glass has negligible effect on sound transmission through the window (although it may be useful for avoiding problems with optical reflections). Using two different thicknesses of glass gives a small improvement in STC. This is discussed in J.D.Quirt, Sound Transmission Through Windows, CBD 240, Division of Building Research, National Research Council Canada, Ottawa, 1985.
