Importance Of Filters; Dust - Mitsubishi Electric Lossnay series Technical Manual

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CHAPTER 8 Filters

1. Importance of Filters

Clean air is necessary for comfort and health. Besides atmospheric pollution that has been generated with the development of
modern industries, the increased use of automobiles, air pollution in air-tight room has progressed to the point where it has an
adverse effect on occupants.
Also, demands for preventing pollen from entering inside spaces are increasing.

2. Dust

The particle diameter of dust and applicable range of filters are shown in Table 1, and representative data regarding outdoor air
dust concentrations and indoor dust concentrations is shown in Table 2.
Table 1. Aerosol particle diameters and applicable ranges of various filters
Table 2. Dust Concentrations
Type
Outdoor air dust
concentration
Indoor dust concentration
Remarks:
1. Outdoor dust is said to have a diameter of 0.08 mil (2.1 µm); the 11 types of dust (average diameter 0.08 mil (2.0 µm)) as
listed by JIS Z8901 for performance test particles are employed.
2. Dust in office rooms is largely generated by cigarette smoke, and its diameter is 0.028 mil (0.72 µm). The 14 types of dust
(average 0.031 mil (0.8 µm)) as listed by JIS Z 8901 for performance test particles are employed.
3. Dust generated in rooms where there is no smoking has approximately the same diameter as outdoor air.
4. Smoking in general offices (Japan):
Percentage of smokers
Average number of cigarettes : Approx. 1/person·h (including non-smokers)
Length of cigarette (tobacco section) : Approx. 1.6 inch (4 cm)
Amount of dust generated by one cigarette : Approx. 3.5 × 10
U-76
Aerosol particle diameter (mil)
1.2×10
-5 -4 -3
3.94×10 3.94×10 3.94×10
Solid
Fumes
particles
Fluid
Mist
particles
Clay
Oil fumes
Tobacco smoke
Major
Carbon black
particles
ZnO fumes
Sea salt
particles
Viruses
Atmospheric
dust
Air filters
HEPA filter
Large city
Small city
Industrial districts
General office
Stores
Applications with no tobacco smoke
: Approx. 70% (adult men)
-2
-2 -1
3.9×10 3.9×10 3.9 39
Dust
Sprays
Mud Sand
Fry ashes
Coal dust
Cement
Pollen
Bacteria Hair
Medium to high efficiency filters
Fine dust, coarse
dust fillers
Reference Data
6.24 - 9.36 × 10
6.24 × 10 -9
1.25 × 10 -9
3.5 × 10
-4 (ounce/h)
0.00018 (ounce/h)
0.00018 (ounce/h)
-4
ounce/cigarette (10 mg/cigarette)
-9 3
(lb/ft ) 0.1 - 0.15 mg/m
3 3
(lb/ft ) 0.1 mg/m or less
3 3
(lb/ft ) 0.2 mg/m or more
10 mg/h per person
5 mg/h per person
5 mg/h per person
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