Siniat A1 Shaftwall systems were tested for fire resistance without insulation in the cavity. As such it is not possible to include glasswool insulation within the cavity of the system to improve acoustic performance as it will invalidate the fire test.

In order to improve acoustic performance you will need to consider additional layers of board to the shaftwall or for greater performance gains a separate lining system installed in front of the shaftwall and insulate the cavity created between the two systems.