Firecrunch has a high acoustic rating in its natural format in 10mm, and higher in greater thicknesses.
The BCA requirement levels are met by the addition of high density acoustic insulation batts placed in the wall and ceiling cavities etc to the architects and or manufacturers specification.
In some cases these are fire and acoustic rated batts. (For further info on fire batts see web site)
These are available from several manufacturers in Australia and users should check with these organisation first to verify the ability relevant to those specified Rw and other requirements