| 摘要 |
<p>A duct (10) is cast into a concrete wall (30) during construction. The duct is located within a sleeve (11) at one end (12) of which has a fixture (16) with a void (17) around space (18) for a barrier (19) and seal (14). The other end (13) of the sleeve (11) has a ring-shaped membrane seal (15).</p> |
