Reference for Shabbat 292:5
כתנאי אין חותכין שפופרת ביו"ט וא"צ לומר בשבת נפלה (אין) מחזירין אותה בשבת ואין צריך לומר ביו"ט ור' יאשיה מיקל
A closed house [room] does not defile all around it; if he had broken through the door-frame, it defiles all around it.<span class="x" onmousemove="('comment',' If a room containing a corpse is closed, i.e., the door is walled up, the defilement of the corpse does not extend beyond it. But if the door-frame was first broken and then walled up, so that no aperture at all is visible, the house is regarded as a grave and defiles everything around it to a distance of four cubits. — Thus an opening must be absolutely closed before it ceases to count as such, and the same applies to the cask. ');"><sup>8</sup></span> [The insertion of] a tube,<span class="x" onmousemove="('comment',' I.e., into a barrel, as a pipe. ');"><sup>9</sup></span>