kojak

Does anyone know how to grade the acoustic rating of an acoustic floor buildup? I have been recommended the following for my flat which is in a 1930's London mansion block: 2 layers of 18mm floorgrade chipboard on 40mm mineral wool acoustic insulation of 200kg/cub m density on concrete slab 125 or 150mm thick In other words, what dB rating will this buildup achieve for airborne and footfall sound? The building Regs Part E require, I think, 45dB for airborne and 62dB for footfall. Thanks very much.