When it is necessary to work in oxygen deficient atmospheres, supplied air must be provided.Air can be supplied with either an air-supplied face mask or self-contained breathing apparatus (SCBA).
英
美
- 当必须工作在缺氧空气中时;必须提供补给空气.;使用空气补给面罩或自给式呼吸器(SCBA)来补给空气