Steel tube for building structures or frames - with refractory sheath and outer plastic tube

摘要

Steel tube or bar is inserted in a tube made of plastic to form an annular gap which is filled with a non-combustible solid refractory. The refractory is pref. a cement mortar, which may also contain a material with thermal insulating properties, e.g. perlite or vermiculite, and/or glass- or steel- fibres; the refractory may also contain a wire coil or grid providing reinforcement. Used in all types of construction, e.g. framework for light roof structures. The outer plastic tube may have a desired colour and/or serve as a good base for paint, the plastic providing excellent resistance to corrosion. The refractory coating prevents or retards the collapse of the steel tube or bar from heat in the event of a fire.