Domestic, outdoor air, all ages (TWA) - 9 ppm*, 8 hrs.
American Gas Association -
Indoor air (leakage at a heat register) - 15 ppm
American Society of Heating, Refrigeration & Air Conditioning Engineers (ASHRAE) -
Indoor air (leakage at a heat register) - 9 ppm
Common Action Level -
Indoor air (most common CO level triggering action by local Authorities of Jurisdiction) - 9 ppm
TWA - Computed by making measurements at intervals over 8 hours, then adding the sums of the concentrations and the intervals, and dividing by 8 hours (480 min.).
* Based on several published studies of people with coronary ischemic disease showing ECG changes during moderate exercise when breathing concentrations of CO giving 3% COHb.
...... last changed 08/23/00
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