Table 8.5.

Suggested lower limit of velocity [16]

Cleanroom	Lower limit of air velocity (m/s)	Condition
Vertical unidirectional flow	0.12	No occupant during ordinary times or rare pass in and out, no obvious heat source
	0.3	With the general condition without obvious heat source
	≯0.5	With occupant inside and obvious heat source. If it is still not feasible to set 0.5, the size of the heat source should be controlled, and isolation measures should be taken
Horizontal unidirectional flow	0.3	No occupant during ordinary times or rare pass in and out
	0.35	General condition
	≯0.5	With higher requirement or frequent pass in and out