The invention relates to a roller shutter for opening and closing a doorway (12) having a door blade (11), the door blade (11) comprises several rigid shutter elements (13) which are hinged with each other, the shutter elements (13) are guided by side rails (18) at opposed sides of the doorway (12), wherein each shutter element (13) provides an end piece (19) at each horizontally spaced end of the shutter element (13) for spacing layers of rolled up shutter elements (13) apart from each other, each end piece (19) has at least one concave section (27) for coiling the end pieces (19) on a coiling device (14) and/or in layers on top of each other. For reducing the risk of weakening a connection between the end piece (19) and the shutter element (13), for reducing noise and/or vibrations during the opening and/or closing of the door way and/or to increase the stability of the roller shutter the roller shutter (10) is characterized in that at least some of the end pieces (19) having at least one plane gliding section (28), the plane gliding section (28) is arranged for interacting with a slide guide (36) of the side rail (18) for leading the end pieces (19) into and/or out of the side rails (18).

Door with a door leaf which, starting from a closed position, can be wound up to form a multi-layer winding in the course of an opening movement and has a plurality of slats which customarily extend horizontally with their longitudinal axes approximately perpendicular to the direction of the opening movement, and with a guide arrangement for guiding the opening movement comprising preferably helically shaped guide rails in the region of the lateral edges of the slats in planes extending approximately perpendicularly to the longitudinal axes of said slats, and guide elements mounted on lateral edges of the slat which leads during the opening movement can be introduced into the radially outermost windings of said guide rails, wherein the guide elements (42) are fastened to the lateral edges of the leading slat (40) via pivot levers (50) on the leading slat and are mounted on the slat so as to be pivotable with respect to pivot axes extending parallel to the longitudinal axis of the slat.

A passive flood barrier that self-deploys to prevent or limit the passage of flood water through an opening in a structure such as a ventilation shaft. The passive flood barrier device includes a buoyant volume extending across at least a portion of the structural opening. The buoyant volume is configured to float in response to flood water near the structural opening. A flexible flood barrier is coupled to the buoyant volume. The flexible flood barrier is deployable from the buoyant volume as the buoyant volume travels upward in response to flood water near the structural opening.