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Smoke protection dampers are used in ventilation plant rooms or in ducts to prevent smoke from spreading. For more information see: www.trox.de/en/87a57f6ecbf530ed. Smoke protection dampers for use in ventilation plant rooms or in ducts to prevent smoke from spreading; frame made from C-sections, with aerodynamically profiled hollow blades and external linkage, spring return actuator, with general building inspectorate licence Z-78.4-51 from the DIBt, Berlin, Germany. Can be triggered by duct smoke detectors with general building inspectorate licence, e.g. TROX duct smoke detector RM-O-VS-D or RM-O-3-D.