Table 14.9.

Comparison of the size of clean area when N _a/N _b < 1 %

No.	Condition	Air supply velocity in clean area (m/s)	Total flow rate/(m3/h)	Ratio of the minimum side length of the cross section in clean area at the working height to the side length of the air supply cross section (%)	The minimum cross-sectional area in the clean area at the working height (m2)	Ref.
1	150 mm air curtain	0.31	8,743	105	2.1 × 2.1	[19]
2	100 mm air curtain	0.31	8,743	85	1.7 × 1.7
3	75 mm air curtain	0.31	8,743	85	1.7 × 1.7
4	225 mm air curtain	0.3	11,529	131	Convert with square: 2.4 × 2.4
5	75 mm air curtain	0.3	6,561	60	Convert with square: 1.51 × 1.51	[9]
6	Vertical unidirectional flow without air curtain	0.31	4,397	64	1.28 × 1.28	[19]
7	Vertical unidirectional flow without air curtain	0.5	7,200	78.7	Convert with square: 1.64 × 1.64	[9]