| 摘要 |
PROBLEM TO BE SOLVED: To provide an incombustible and heat insulating duct excellent in incombustibility, heat insulation and productivity, and having flexibility. SOLUTION: Glass wool or other heat insulating material (2) is enveloped by an incombustible cloth or other incombustible sheet type material (3) to form a belt type member (1). Then, the belt type member (1) is spirally wound to form the duct. At this time, the end of a preceding belt type member is bonded to the end of a succeeding belt type member so as not to deteriorate the incombustibility or integrally connected thereto by an incombustible connecting member (5). |
