Televised ducts under slab floor. Ducts are concrete possibly transite with asbestos. Concrete ducts look in good condition but metal fittings are very rusted. Metal fittings would need to be spin cast mortared then the entire system spray lined with Duct Armor duct lining material, but several locations in the floor would need to opened up in order to provide proper access to the ducts. The registers are too small to fit mortared equipment in.