| 摘要 |
The system passes a chimney through a concrete roof, using a guide member. A number of first holes are drilled to the same pattern as the ventilation passages (3) in the member, followed by further holes to that of the fume passages (7). Part (5) of the member, whose external dimensions match those of the holes drilled, is inserted in the roof. A flange (2) is finally fitted to the member. ADVANTAGE - Simplicity and low cost. |
