Today’s tip starts with a reminder: occupational exposure to heat (indoors or outdoors, with or without direct sunlight), in any work situation, implies a thermal overload to the worker – and the consequent potential health risks!
And what should be done to prevent heat from harming the worker? Always control the activity.
There are two measures to control occupational exposure to heat. They are:
– Human control
– Environment control
Human control” means medical monitoring, air conditioning of the work environment, water ingestion, limitation of exposure time to heat, and the proper Personal Protection Equipment (PPE). “Environmental control”, on the other hand, would be the physical barriers and ventilation in the workplace.
NR15 deals with intermittent work with excessive exposure to heat. Check it out:
NR 15 – UNHEALTHY ACTIVITIES AND OPERATIONS
ANNEX III
TOLERANCE LIMITS FOR EXPOSURE TO HEAT
Tolerance limits for exposure to heat during intermittent work with rest periods at the work site.
1. Exposure to heat must be evaluated by means of the “Wet Bulb Globe Temperature ” – WBGT defined by the following equations:
• Indoor or outdoor environments without solar radiation: WBGT = 0.7 tbn + 0.3 tg
• Outdoor environments with solar radiation: WBGT = 0.7 tbn + 0.1 tbs + 0.2 tg
• where:
tbn = natural wet-bulb temperature
tg = globe thermometer temperature
tbs = dry-bulb temperature.
2. The devices that should be used in this evaluation are: natural wet-bulb thermometer, globe thermometer, and common mercury thermometer.
3. The measurements must be taken in the place where the worker stays, at the height of the most affected body region.
Tolerance limits for exposure to heat, in intermittent work with rest periods at the work site.
TABLE NO. 1 TYPE OF ACTIVITY
Intermittent work with rest periods at the work site (per hour) Light Moderate Heavy
Continuous work up to 30.0 up to 26.7 up to 25.0
45 minutes work / 15 minutes rest 30.1 to 30.5 26.8 to 28.0 25.1 to 25.9
30 minutes work / 30 minutes rest 30.7 to 31.4 28.1 to 29.4 26.0 to 27.9
15 minutes work / 45 minutes rest 31.5 to 32.2 29.5 to 31.1 28.0 to 30.0
No work is allowed without appropriate control measures above 32.2 above 31.1 above 30.0