The following definitions are commonly used for the sound insulation value:
- Rw = "weighted sound insulation value" of the window installed in the test bench (laboratory value). Manufacturers of window elements usually specify this value.
- R'w = "assessed sound insulation value" of the window installed on the building. The apostrophe shows that when a window is installed, sound is also transmitted via side paths (flanking components). In VDI 2719, this is assessed with a discount of -2 dB, so that R'w = Rw – 2 dB. DIN 4109 specifies a formula for this in its axe sheet 3 that leads to more detailed results.
- R'w, res = the "resulting sound insulation value" is the sound insulation value of the entire component calculated from the individual sound insulation dimensions of the partial surfaces (e.g. window, wall, door, etc.). For example, an outer wall including its windows.
Source: bauwion
