Medicines and Related Substances Act, 1965
R 385
Occupational Health and Safety Act, 1993 (Act No. 85 of 1993)RegulationsRegulations for Hazardous Chemical Agents, 2020AnnexuresAnnexure 3 : Hazardous Chemical Agent GuidelinesGuidance on medical surveillance and biological monitoringMixed exposuresThe 8-hour reference period |
| 88. | The term "8-hour reference period" relates to the procedure whereby the occupational exposures in any 24-hour period are treated as equivalent to a single uniform exposure for eight hours [the 8-hour time weighted average (TWA) exposure]. |
The eight-hour TWA may be represented mathematically by:
where C1 is the occupational exposure value (concentration) and T1 is the associated exposure time in hours in any 24-hour period.
