JULY 7, 2021 – Heat is one of the leading weather-related causes of death in the United States, resulting in hundreds of fatalities each year and even more illnesses. During extremely hot and humid weather, your body’s ability to cool itself is challenged. When the body heats too rapidly or when too much fluid or salt is lost through dehydration or sweating, the body’s temperature rises and experiences a heat-related illness. It is important to know the symptoms of excessive heat exposure and the appropriate responses to protect yourself or someone you care about.
To support safety awareness during hazardous heat conditions, naval installations utilize color-coded flags that are flown in strategic locations. These color-coded flags communicate hazardous conditions to personnel so that work and outdoor activity can be adjusted and limited accordingly.
The Wet Bulb, Globe Temperature (WBGT) Index is the most effective means of assessing the effect of heat stress on the human body. The WBGT Index is used to determine flag conditions as a safety standard for how long individuals can safely work outdoors in hot and humid conditions. Knowing and understanding these flag conditions will help keep you safe from heat-related emergencies like heat cramps, heat exhaustion, and heat/sun stroke.
A White Flag indicates a WGBT Index less than 80 degrees and extremely intense physical exertion may increase the risk of heat exhaustion or heat stroke; therefore, caution should be taken.
The Green Flag indicates a WGBT Index of 80 – 84.9 degrees and discretion is required in planning intense work and exercise. This is a marginal heat stress limit for personnel.
The Yellow Flag indicates a WGBT Index of 85 – 87.9 degrees and strenuous exercise and activities should be shortened. The Red Flag indicates a WGBT Index of 88 – 89 degrees and strenuous exercise is shortened.
Lastly, The Black Flag indicates a WGBT Index of 90 degrees and above, physical training and strenuous exercise is suspended for all personnel (excluding operational commitments).
Excessive heat poses a significant risk to people’s health, including heat stroke and heat exhaustion, which can result in death. Excessive heat generally means unusually hot temperatures, possibly combined with oppressive humidity that persists for two or more days. Knowing how to identify the symptoms of excessive heat exposure, heat exhaustion, heat stroke, and then knowing the appropriate response to take, is vital in preventing heat injuries and even saving lives.
Story by Jason Scarborough
Norfolk Naval Shipyard