Table 4.4.

Judgment criterion of unqualified leakage for air filter with qualitative and quantitative tests

Type	Efficiency at nominal flow rate	Local leakage limit with qualitative test, sampling period	Local leakage limit with quantitative test
	%		%
A	99.9 (sodium flame method)	Downstream particle sampling count for diameter ≥0.5 μm is ≥3 pc/min (corresponding upstream concentration must ≥3 × 104pc/L)	1
B	99.99 (sodium flame method)		0.1
C	99.999 (sodium flame method)		0.01
D	99.999 (particle counting method, 0.1–0.3 μm)	Downstream particle sampling count for diameter ≥0.1 μm is ≥3 pc/min (corresponding upstream concentration must ≥3 × 106pc/L)	0.01
E	99.999 9 (particle counting method, 0.1–0.3 μm)		0.001
F	99.999 99 (particle counting method, 0.1–0.3 μm)		0.0001