Provide mechanical ventilation to maintain vapor concentrations below permissible exposure levels.
Provide mechanical ventilation to maintain vapor concentrations below permissible exposure levels.
提供机械通风，将气体浓度控制在允许的逸出量以下。
Provide mechanical ventilation to maintain vapor concentrations below permissible exposure levels.
提供机械通风，将气体浓度控制在允许的逸出量以下。