Before revision: Smaller concentrations can be harmful over longer periods of time while increasing concentrations require diminishing exposure times to be harmful.NFPA 720: Standard for the Installation of Household Carbon Monoxide (CO) Warning Equipment, 2005 Edition, Annex B Dangers of Carbon Monoxide, B.1 Carbon Monoxide, Table B.1 Symptoms of Carbon Monoxide Exposure Based on Concentration CO detectors are designed to measure CO levels over time and sound an alarm before dangerous levels of CO accumulate in an environment, giving people adequate warning to safely ventilate the area or evacuate.
After revision: Smaller concentrations can be harmful over longer periods while increasing concentrations require diminishing exposure times to be harmful.NFPA 720: Standard for the Installation of Household Carbon Monoxide (CO) Warning Equipment, 2005 Edition, Annex B Dangers of Carbon Monoxide, B.1 Carbon Monoxide, Table B.1 Symptoms of Carbon Monoxide Exposure Based on Concentration CO detectors are designed to measure CO levels over time and sound an alarm before dangerous levels of CO accumulate in an environment, giving people adequate warning to safely ventilate the area or evacuate.