| 摘要 |
Apparatus and a method for extending the length of a vent pipe for a predetermined distance above the elevation of a building roof includes an elongated extension pipe connectable with the vent pipe, a flashing attachable to the roof while fitted as a sleeve over the extension pipe, and a vent cap fittable over the flashi ng and the extension pipe. The vent cap includes an opening for venting to external atmosphere gases received by the extension pipe from the vent pipe. The extension pipe and the vent cap are sized so as to maintain a venting pressure in the extension pipe not greater than the venting pressure in the extension pipe.
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