IEC 60079-29-4:2009规定了环境空气中可燃气体或蒸汽检测和测量设备的性能要求，方法是测量气体或蒸汽在延伸光路（通常从一米到几公里）上的光谱吸收。这种设备以单位测量光路上吸收气体的整体浓度，例如可燃气体的LFL计。本标准补充和修改了IEC 60079-0的一般要求。如果本标准的要求与IEC 60079的要求冲突- 0时，应以本标准的要求为准。 本副本包含2010年8月勘误表的内容。

IEC 60079-29-4:2009 specifies performance requirements of equipment for the detection and measuring of flammable gases or vapours in ambient air by measuring the spectral absorption by the gases or vapours over extended optical paths, ranging typically from one meter to a few kilometres. Such equipment measures the integral concentration of the absorbing gas over the optical path in units such as LFL meter for flammable gases. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard shall take precedence. The contents of the corrigendum of August 2010 have been included in this copy.