This is from a state OSHA plan that has released its State Emphasis Program (SEP) for Heat-Related Hazards. In this SEP there are some great questions we can ask of our own Heat-Related Injury and Illness Prevention Plans to see if our plan is meeting basic OSHA compliance.
Here are a couple of KEY points to consider:
- Is your facility able to measure Dry Bulb Temperature, and are you testing for this in “cool down areas”?
- Is your facility able to measure Wet Bulb Temperature, and are you testing for this in suspected high temp exposure areas/jobs/tasks?
- Are breaks based on the data from these measurements?
- Is your facility using Administrative Controls (earlier start times, personnel rotation, etc.) to reduce exposure to heat-related hazards?
The Dry Bulb temperature, usually referred to as air temperature, is the air property that is most commonly used. When people refer to the temperature of the air, they are normally referring to its dry bulb temperature. The Dry Bulb Temperature refers basically to the ambient air temperature. It is called “Dry Bulb” because a thermometer indicates the air temperature and is not affected by the air’s moisture.
The Wet Bulb temperature is the temperature of adiabatic saturation. This is the temperature indicated by a moistened thermometer bulb exposed to the airflow. Wet Bulb temperature can be measured using a thermometer with the bulb wrapped in wet muslin. The adiabatic water evaporation from the thermometer and the cooling effect is indicated by a “wet bulb temperature” lower than the “dry bulb temperature” in the air.