COLTON HEATING & COOLING
  • 315 E. Elm St. Wheaton, IL 60189

ALLOWABLE EXPOSURE LEVELS TO CARBON MONOXIDE

Allowable (Legal) Limits for Carbon Monoxide

  • Permissible Exposure Limit (PEL, by TWA) – 50 ppm, 8 hrs.
    Old PEL Standard (by TWA) – 35 ppm, 8 hrs.
    Threshold Limit Value (TLV, by TWA) – 25 ppm (29 mg/cu. m)
    (recommended by American Conference of Governmental & Industrial Hygienists ACGIH)
    Ceiling (max. value, 15 min.) – 200 ppm (229 mg/cu. m)

PEL (Industry, by TWA) – 35 ppm, 8 hrs. (38.5 mg/cu. m)
PEL (Construction, by TWA) – 50 ppm, 8 hrs. (55 mg/cu. m)
Ceiling (max. value) – 200 ppm (229 mg/cu. m)

  • Domestic, outdoor air, all ages (TWA) – 9 ppm*, 8 hrs.
    Domestic, outdoor air, all ages (TWA) – 35 ppm, 1 hr.

Domestic, outdoor air, all ages (TWA) – 9 pm*, 8 hrs.

Indoor air (leakage at a heat register) – 9 pm

Indoor air (leakage at a heat register) – 15 pm

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.