| 摘要 |
A smoke release and ventilation system comprises a frame housing upper and lower members each slidable in the frame between a normally closed position and an open position, the upper member being retained in its upper position by retaining element, for example an electromagnetic, the upper member being heavier than the lower member whereby, on release of the retaining, the upper member falls under gravity to its open position, and, consequential upon said fall of the upper member and the kinetic energy thereof, the lower member is raised to its open position, thereby providing gaps above and below the members and through which smoke can escape.
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