A SYSTEM FOR INHIBITING THE SPREAD OF FIRE IN A BUILDING STRUCTURE

摘要

A duct section of an air conditioning system near an outlet thereof from a compartment of a building has a hinged closure flap (21) held by a releasable latch device in a position allowing fluid flow along the duct and covering a vent aperture (20) in the wall of the duct. The latch device is released by control means responsive to the presence of combustion in the building compartment, e.g. a smoke detector or a temperature sensitive device, whereby the closure flap (21) drops to close the duct and to open the vent aperture. In this way the products of combustion are returned to the building compartment to assist in dousing the conflagration or are passed to a vent duct leading outside the building structure. IMAGE