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In the case of Japan, an Instruction Guideline based on these regulations has been issued, and unified guidance is carried out.
Part of the Instruction Guideline regarding ventilation is shown below.
The fresh outdoor air intake must be 10 m or higher from ground level, and be distanced appropriately from the exhaust air
outlet. (Neighbouring buildings must also be considered.)
The fresh outdoor air intake volume must be 25 to 30 m
An air volume measurement hole must be installed at an effective position to measure the treated air volume of the
ventilating device.
The position and shape of the supply diffuser and return grille must be selected so the air environment in the room is
distributed evenly.
1.2 Effect of air contamination on human bodies
Effect of oxygen (O
) concentration
2
Concentration (%)
Approx. 21
Standard atmosphere.
Ventilation air volume standard will be a guideline where concentration does not decrease more than 0.5%
20.5
from normal value. (The Building Standard Law of Japan)
An oxygen deficiency of this amount does not directly endanger life in a normal air pressure, but if there is a
20 - 19
combustion device in the area, the generation of CO will increase rapidly due to incomplete combustion.
18
Industrial Safety and Health Act. (Hypoxia prevention regulations.)
16
Normal concentration in exhaled air.
16 - 12
Increase in pulse and breathing resulting in dizziness and headaches.
15
Flame in combustion devices will extinguish.
12
Threat to life in short term.
7
Fatal
Effect of carbon monoxide (CO)
Concentration (ppm)
0.01 - 0.2
Standard atmosphere.
5
Considered to be the long-term tolerable value.
The Building Standard Law of Japan, Law for Maintenance of Sanitation in Buildings.
10
Environmental standard 24-hour average.
Considered to be the short-term tolerable value.
20
Environmental standard 8-hour average.
Tolerable concentration for labor environment.
50
(Japan Industrial Sanitation Association)
No effect for 3 hours. Effect noticed after 6 hours.
100
Headache, illness after 9 hours; harmful for long-term but not fatal.
200
Light headache in the forehead in 2 to 3 hours.
400
Headache in the forehead, nausea in 1 to 2 hours; headache in the back of head in 2.5 to 3 hours.
800
Headache, dizziness, nausea, convulsions in 45 minutes. Comatose in 2 hours.
1,600
Headache, dizziness in 20 minutes. Death in 2 hours.
3,200
Headache, dizziness in 5 to 10 minutes. Death in 30 minutes.
6,400
Death in 10 to 15 minutes.
12,800
Death in 1 to 3 minutes.
Several 10,000 ppm
This level may be found in automobile exhaust.
(Several %)
CHAPTER 1
3
/h·person in design.
Standards and effect of concentration changes
Effect of concentration changes
Ventilation for Healthy Living
10,000 ppm = 1%
Apprpx. 5 ppm is
an annual
average value in
city areas.
This value may
exceed 100 ppm
near roads, in
tunnels and
parking areas.
3
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