When working in hot climates, workers are kept cool with cooling vests.
An air-cooled vest is worn by the workers which transfers cool air over their torsos by using compressed air.
It is common for workers to wear vests with pockets that contain inserts that allow them to remain cool while they work. In order to use the inserts, they must be frozen or chilled beforehand. Because of their ability to maintain a constant body temperature no matter what the ambient temperature is, they are often worn in situations of extreme heat. The vest will usually be worn while wearing a full protective suit of clothing that does not permit air to circulate around the wearer in order to keep him or her cool at all times.
There are inserts located in the pockets of high-visibility vests that are designed to enable workers to stay cool while on the job. Before inserts can be used, they must be frozen or chilled for use. During times of extreme heat, they are often worn to keep the body at the same temperature regardless of the temperature outside so they keep the body at the same temperature throughout the day. It is most commonly used when wearing protective clothing where air cannot circulate to cool the clothing as it does with evaporative cooling vests. As a result of bright colors and reflective material on both the front and the back of the garments, high-visibility garments improve worker visibility while on the job.
In order to keep workers cool, evaporative cooling vests are used. As opposed to insert-cooled vests, whose cooling efficiency is fixed regardless of the ambient air temperature, ambient air cooled vests have a variable cooling efficiency that increases or decreases depending on the ambient air temperature. A vest cooled by evaporative cooling cannot perform the same as a vest cooled by insert cooling in high humidity since evaporative cooling is not as efficient. Also, when they are worn under full suits that do not permit air circulation, they do not provide adequate cooling as a result of the lack of circulation.