Class Ⅰ: coal mine underground electrical equipment;
Class Ⅱ: in addition to coal mines, underground, all other electrical equipment for explosive gas environment.
Type II can be divided into Ⅱ A, Ⅱ B, Ⅱ C, mark Ⅱ B equipment can be applied to Ⅱ A equipment conditions; Ⅱ C can be applied to Ⅱ A, Ⅱ B conditions of use.
Category III: in addition to coal mines other than explosive dust environment electrical equipment.
ⅢA: combustible flotsam; ⅢB: non-conductive dust; ⅢC: conductive dust.
China's law provides that enterprises, institutions and other producers and operators that emit pollutants should take measures to prevent and control the pollution and hazards to the environment arising from waste gas, waste water, waste residue, medical waste, dust, malodorous gases, radioactive substances, and noise, vibration, optical radiation, electromagnetic radiation and other pollution and hazards to the environment generated in the course of production and construction or other activities.
Legal basis
Article 42 of the Environmental Protection Law: Enterprises, institutions and other producers and operators emitting pollutants shall take measures to prevent and control pollution and hazards to the environment caused by waste gas, waste water, waste residue, medical waste, dust, malodorous gases, radioactive substances, as well as by noise, vibration, optical and electromagnetic radiation generated in the course of production and construction or other activities. Enterprises and institutions discharging pollutants shall establish a system of responsibility for environmental protection and clarify the responsibilities of unit heads and relevant personnel. Key emission units shall install and use monitoring equipment in accordance with relevant state regulations and monitoring specifications, to ensure the normal operation of monitoring equipment, save the original monitoring records. It is strictly prohibited to discharge pollutants illegally through concealed pipes, seepage wells, seepage pits, irrigation or tampering, falsification of monitoring data, or improper operation of pollution prevention and control facilities to avoid supervision