| 摘要 |
The metal, wood or composite material beam (3) sections are almost totally surrounded by sleeving. The sheathing consists of an external metal, textile or polymer cover (7) which is fastened to the beam by a self tapping screw (9). A porous rock wool refractory insulation (8) fills the space between the sheath and the beam, except for the space occupied by pipes (10), with micro perforations (11), which pass through the sheath. The sheath is also micro-perforated with holes (12).In the event of fire the pipe diffuses water through its perforations into the insulating material. The diffused water is partially vaporised and the sheath perforations allow passage of this vapour and excess water This vaporisation then cools the assembly and limits overheating and structural damage.
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