1. Work surface unevenness < 20mm; relatively dry and free of water; slope < 25°
2. Ambient temperature: -20°C to 60°C; steel plate surface temperature at least 3°C above the dew point
3. Humidity:
a. Relative humidity not exceeding 90% for steel blasting
b. Relative humidity not exceeding 95% for concrete blasting
4. Altitude: 0 to 3000m; operation is not permitted in rain or snow
