轨交材料烟毒测试FTIR的抽气流量标准变更，需要纠结抽气流量吗？
EN45545-2-2020指定的EN17084-2018把流量4L建议为1.5L。5.1.7 Sampling flow rate.The sampling flow rate shall be maintained to (1,5±0,1) l/min during the test.1) No influence has been found on smoke density measurement according to EN ISO 5659-2.2) The volume drawn out of the chamber during 20 min is limited so as to avoid any under-pressure effects inside the Smoke Chamber.在20分钟内从燃烧室中抽出的体积要有限制，以避免烟雾室内部产生任何负压效应。
EN45545-2-2015，烟毒测试采样时应使用(4±0.5)l/min的流量，以免在采样室中压力过大的情况下以及在采样气体时对连续烟气密度测量产生任何干扰。A flow rate of (4±0,5) l/min shall be used for sampling in order to avoid an under pressure condition of the chamber and any interference on the continuous smoke density measurement when the gases are sampled.
怎么控制流量的？