Units in this sub-class include the manufacture of: •refractory ceramic goods like refractory bricks •structural non-refractory clay building materials like ceramic bricks •refractory ceramic goods: tiles and pipes •non-refractory ceramic hearth or wall tiles, mosaic cubes etc. •structural non-refractory clay building materials: roofing tiles, chimney pots, pipes, conduits, etc. •flooring blocks in baked clay •refractory mortars and/or concretes manufacturing •refractory ceramic goods: heat-insulating ceramic goods of siliceous fossil meals and/or blocks etc., retorts, crucibles, muffles, nozzles, tubes, etc. manufacturing •non-refractory ceramic flags and/or paving manufacturing •ceramic sanitary fixtures manufacturing •refractory articles containing magnesite, dolomite or chromite manufacturing