Rockwool - Expanded Polystyrene Manufacturing Company Standard size for panels : 1200x600x50/75mm or Multilayer; Standard size of the Blankets : 1.2 x 20 meter rolls; Rockwool high density slabs conforming to ASTM C 612 and Equivalent BS – 3958-5 are designed for the thermal and acoustic insulation of flat or slightly curved surfaces operating at temperatures up to 750 º C.