We're sorry, but OSHAcademy doesn't work properly without JavaScript enabled. Please turn on JavaScript or install a browser that supports Javascript.

646 Heat Injury and Illness Prevention: Supervisor Skip to main content

Monitoring Heat Conditions

Indoor Monitoring Methods

The employer must identify each work area where there is a reasonable expectation that employees are, or may be, exposed to heat at or above the initial heat trigger. Additionally, a monitoring plan for each work area should be implemented to determine when employees are exposed to heat at or above the initial and high heat triggers. This monitoring plan must be included in the HSMP.

Methods to Monitor Temperature at the Worksite
Monitoring Methods
  • Measure Heat Index: Use for indoor areas without significant radiant heat sources.
  • Measure Wet Bulb Globe Temperature (WBGT): Use in environments with high heat sources like factories or kitchens, measuring temperature, humidity, radiant heat, and air movement.
Frequency
  • Continuously monitor areas where heat levels are consistently high.
  • Increase monitoring during changes in production, processes, equipment, or controls, or when outdoor temperatures rise significantly. Update the monitoring plan or develop and implement a monitoring plan to account for increases in heat exposure.
Exemptions from Monitoring

The employer can choose to assume that the temperature at a work area will always be at or above the initial and high heat triggers, instead of conducting on-site monitoring or tracking local weather forecasts. If this approach is taken, the employer must implement all control measures required for conditions exceeding the initial and high heat triggers.

The employer must identify all work areas where employees might be exposed to heat at or above the initial trigger.

Knowledge Check Choose the best answer for the question.

4-7. Which monitoring method should be used for indoor areas without significant radiant heat sources?