1. Elevation not exceeding 1000m;
2. Ambient temperature is not higher than +40 ° C, not lower than -20 ° C;
3. Air relative humidity is not more than 95% (+ 25 ° C);
4. There are methane mixed gas and coal dust, and there is a risk of explosion in place;
5. No strong bumps, vibrations and inclination with the vertical plane does not exceed 15 ° environment;
6. Where there is no corrosive gases and vapors of metals and insulating materials;
7. No dripping and watering place.