| 摘要 |
This invention relates to a fire-prevention sheet in which at least one rubber sheet having an oxygen index equal to or more than 28, a thickness of 0.1-3mm and a hydrogen halide gas generation ability of 0-350mg/g, and at least one metal sheet having a thickness of 15-200 mu m are layered. The fire-prevention sheet has the fire spread prevention effect exceeding the level that not all of a sample cable, which would be completely destroyed by fire if it were used as a sample in IEC332-3 category C, is destroyed by fire even in IEC332-3 category A. A layered sheet consisting of a heat expandable rubber mixture in expectation of an expansion ratio equal to or more than 4 and a fabric may be used instead of the above rubber sheet. This invention also relates to a fire-prevention structure in which a perforated part is blocked by a first and a second fire-prevention sheet, and gaps in the contact part of them are filled with a non-hardening type and heat-resistant sealing material, and a layered sheet of an incombustible rubber sheet and a metal sheet is used as the first and the second fire-prevention sheet. Further, wires or cables laid in a pit may be surrounded with a fire-prevention sheet consisting of a rubber sheet and a metal sheet. Sandbags may be disposed thereon. <IMAGE> |
