摘要 |
<p>The passage of thermoplastic, e.g. PVC, pipes through structural walls is surrounded by frames contg. twin metal blades which are pivoted or spring loaded so as to be able to sever heat softened pipe and block the passage through the wall. The blades are sepd. by a gap which traps air to provide additional insulation between the blades. The two blades may be mounted on the same or opposite sides of the plastic pipe. The blades may seal against alongside static partitions integral with the frame or against the adjacent structure. Coatings of intumescent material may be incorporated to seal the fire break after the blades have intercepted the conduit. Pref. the fire-break units avoid use of asbestos-based materials.</p> |