A fireproof curtain that can be dropped downstage of the tabs to separate the audience from the stage in the event of fire. A Safety Curtain is required by most licensing authorities for theatres over 500 seats. The regulations also require that it is raised and lowered at least once in view of each audience (usually during the interval). Usually made from sheet metal and electrically operated, used to be made from iron faced with asbestos and lowered using a hydraulic damping system.