In Japan, an Instruction Guideline based on these regulations has been issued, and unified guidance is followed. Part of the
Instruction Guideline regarding ventilation is shown below.
The ventilation air intake must be 33ft (10m) or higher from ground level, and be located at an appropriate distance from the
exhaust air outlet. (Neighbouring buildings must also be considered.)
The ventilation air intake volume must be 15 to 18 CFM·occupant. (25 to 30 m
An air volume measurement access hole must be installed at an appropriate position to measure the treated air volume of
the ventilating device.
Select the position and shape of the supply diffuser and return grille to evenly distribute the ventilation air in the room.
1.2 Effect of Air Contamination
Effect of Oxygen (O
Ventilation air volume standard is a guideline where concentration does not decrease more than 0.5%
from normal value. (The Building Standard Law of Japan)
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.
Industrial Safety and Health Act. (Hypoxia prevention regulations.)
Normal concentration in exhaled air.
16 - 12
Increase in pulse and breathing; resulting in dizziness and headaches.
Flame in combustion devices will extinguish.
Short term threat to life.
Effect of Carbon Monoxide (CO)
0.01 - 0.2
Tolerable long-term value.
The Building Standard Law of Japan, Law for Maintenance of Sanitation in Buildings.
Environmental standard for a 24-hour average.
Considered to be the tolerable short-term value.
Environmental standard for an 8-hour average.
Tolerable concentration for working environment.
(Japan Industrial Sanitation Association)
No effect for 3 hours. Effect noticed after 6 hours.
Headache, illness after 9 hours; harmful for long-term but not fatal.
Light headache in the frontal lobe in 2 to 3 hours.
Headache in the temporal lobe, nausea in 1 to 2 hours; headache in the back of head in 2.5 to 3 hours.
Headache, dizziness, nausea, convulsions in 45 minutes. Comatose in 2 hours.
Headache, dizziness in 20 minutes. Death in 2 hours.
Headache, dizziness in 5 to 10 minutes. Death in 30 minutes.
Death in 10 to 15 minutes.
Death in 1 to 3 minutes.
Several 10,000 ppm
Level may be found in automobile exhaust.
Standards and Effect of Concentration Changes
Effect of Concentration Changes
Ventilation for Healthy Living
10,000 ppm = 1%
Approx. 5 ppm is
average value in
This value may
exceed 100 ppm
near roads, in