17 SEALANTS AND INSULATION MADE OF EXPANDED, OR FOAMED IN, SILICEOUS, BITUMINOUS OR PLASTIC MATERIAL FOR HEAT AND SOUND FOR USE IN THE BUILDING INDUSTRY; INSULATING PLATES, SANDWICH-LAYERS, PIPES, LININGS; INSULATING MATERIALS, NAMELY, EXPANDED OR INEXPANDED CLAYS, PERLITE, VERMICULITE, SILICA-MATERIALS