CLEAN ROOM

PURPOSE:To prevent introduction of air from worker's area into highly clean area and keep the highly clean area in a predetermined cleanness stably by a constitution wherein air, which flows from the highly clean area into the worker's area or equipment protecting area, is made to circulate and flow toward upper return suction ports. CONSTITUTION:The whole of a clean tunnel 20 is defined from outside by an outer bulkhead 21. The highly clean areas 23, 23 are isolated from respective equipment protecting areas 24, 24 and the worker's area 22 by inner bulkheads 25, 25, arranged at the outside thereof, and screens 26, 26, arranged at the insides thereof. Clean air enters downwardly from high performance filters 29, 29 as shown by arrow signs to fill up the high cleanness areas 23, 23 whereby the areas 23, 23 are purified. The clean air flows into the equipment protecting areas 24, 24 and the worker's area 22 respectively through gaps between equipments 28 and inner bulkheads 25 as well as between the equipments and the screens 26. Air in the worker's area 22 flows upwardly and returns to the high performance filter to circulate through a pre-filter 31 and a duct 30, therefore, introduction of air from the worker's area 22 into the high cleanness area 23 may be prevented.