国外及国内防火阀、排烟阀类概况建设部建筑设计院贺绮华一、国外防火阀现状英、美西方国家，生产防火阀、排烟阀类产品历史较早，而且产品检验标准也比较严格，其构造形式与日本略有区别，技术性能基本上差不多，但耐火时间要求铰长。最常用的还是熔断金属控制的重力式防... Foreign and domestic fire damper, smoke exhaust valve profile Architectural Design Institute of Ministry of Construction He Yehua First, the status of foreign fire damper Britain, the United States and Western countries, the production of fire dampers, exhaust valve products history earlier, and product testing standards are more stringent, Its structure is slightly different from that of Japan, and the technical performance is basically the same, but the refractory time requires hinge length. The most commonly used is the control of the f