8-hour TWA, OEL comparison across 12 jurisdictions, and extended shift adjustment
How to use: Search for a chemical to load its OELs, then add exposure periods (task description, measured concentration, and duration). The 8-hour TWA is calculated automatically and compared against each jurisdiction's limit. Enable shift adjustment to apply a reduction factor for extended work schedules — the OEL comparison table updates in place.
Chemical
Unit:
Exposure periods
Task / description
Concentration (ppm)
Hours
Minutes
Shift adjustmentOff — standard 8 hr/day, 5 day/week
Adjustment model
No adjustment if t½ < 4 hr or t½ > 400 hr. Default 20 hr is conservative (Paustenbach, 2000).
8-hour TWA
—ppm
Total duration
—
Also
—mg/m³
OEL Comparison
Jurisdiction
TWA OEL
STEL / Ceiling
% of OEL
Status
Notation
Search for a chemical above to compare against OELs.