P.28
12. CO2 LEVELS AND GUIDELINES
NIOSH recommendations
250-350 ppm: normal outdoor ambient concentrations.
600 ppm: minimal air quality complaints.
600-1000 ppm: less clearly interpreted.
1000 ppm: indicates inadequate ventilation; complaints such as
headaches, fatigue, and eye/throat irritation will be more widespread.
1000 ppm should be used as an upper limit for indoor levels.
ASHRAE Standard 62-1989: 1000ppm
CO2 concentration in occupied building should not exceed 1000ppm.
Building bulletin 101 (BB101): 1500ppm
UK standards for schools say that CO2 at averaged over the whole
day(i.e. 9am to 3.30pm) should not exceed 1500ppm.
OSHA: 5000ppm
Time weighted average over five 8-hour work days should not exceed
5000ppm.
Germany, Japan, Australia, UK...: 5000ppm
8 hours weighted average in occupational exposure limit is 5000ppm.
