19 Mountings, not of metal, for liquid, steam, gas and compressed air ducts; substances for fire prevention, namely fireproof mortar; prefabricated fireproof partition walls; building and construction materials, and construction elements, not of metal, namely gas and water pressure-tight pipe and cable ducts, including structural components of the aforementioned goods, namely structural frames and mounts adapted for non-metal ducts; fireproof bulkheads, not of metal, namely partitions in breakthroughs or joints in a wall or ceiling having fire prevention functions; formwork aids, not of metal, for cable and pipe ducts; non-metal construction systems for feeding cables, pipes, conduits and other building elements through walls and ceilings; fireproof non-metal construction systems for the feed-through of cables, pipes, conduits and other building elements; feedthrough systems, not of metal, for the feed-through of cables, pipes, conduits and other building elements through firewalls; feedthrough systems, not of metal, for the feed-through of cables, pipes, conduits and other building elements through ceilings.