Page 195 - Electrical Installation in Hazardous Area

Area classification practice for dusts 159

Ground

Fig. 6.1 Cyclone and bag filter. x = 1.5 m, y = 1.5 m, z = 2 m

Roof

Wall Wall

Fig. 6.2 Manually loaded hopper without air purge inwards through manhole in a
building. X = 1.5 m. Notes: (1) The area below loading floor level is not
addressed. (2) Where air is drawn into the hopper through the manhole, the
dust cloud producing the Zone 21 will not exist provided airflow at manhole
mouth is at least 1 m/s inwards. (3) If housekeeping is sufficient to prevent
any layers forming the Zone 2 may be limited to 2-2.5 m around the hopper