ppm Symptoms and applicable standard
0-1 Normal background levels
9Maximum indoor air quality level: Maximum
allowable concentration per ASHRAE Residential
standards 62-1989 for living area.
25 Maximum limit 8 hrs. of continuous exposure per
California OSHA workplace standards.
35 Maximum 8 hrs. average exposure level per US
OSHA workplace standards.
50 Maximum concentration for continuous exposure in
any 8 hrs. average level per OSHA standards.
100 Remove employees from enclosed space if the CO
concentration exceeds 100ppm per OSHA exposure
limit.
200 Mild headache, fatigue, nausea and dizziness in
2-3 hrs.
400 Frontal headache, life threatening after 3hrs.
Maximum concentration in flue gas per the US EPA
and AGA standards.
800 Dizziness, nausea, convulsions, death in 2-3 hrs.
1600 Loss of consciousness in 1 hr., death in 1-2 hrs.
UTLC11 Manual.indd 2 3/12/14 4:00 PM
