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Evaporative Coolers Prevent Heat Stress Among Farm Workers

Evaporative Coolers Prevent Heat Stress Among Farm Workers

Farm work is unusually dangerous. Of the 335,000 worker deaths that occur every year all over the world, half of them occur on farms. Besides machine accidents and animal attacks, farm workers are also at risk from the sun and working conditions out in the fields. Over 650 farm workers die from heat stress every year while harvesting, planting, or maintaining crops. Many more become sick or incapacitated. Reducing the dangers of heat and humidity, and keeping workers healthy is a special challenge for farmers. Traditionally, their best tools have been water, rest, and shade, but now they have a new way to prevent heat stress: evaporative coolers, also known as swamp coolers. Evaporative coolers can lower temperatures over extremely large areas and reduce the risk of heat stress in even the worst conditions.

Heat Stress & Farm Workers

Most farm work is not only performed in direct sunlight, in large opens areas with little shade, but it often takes place during the hottest months of the year as well. In open fields, temperatures spike, sometimes reaching 8-10°F above the temperature reported by the National Weather Service. The extreme heat is often exacerbated by the nature of the work itself. People performing physical labor expend four times as much energy as people working behind a desk, and the heavy clothing farm workers wear to protect them from pesticides and sunburn - long sleeves, long pants, boots, scarves, and gloves - prevents their bodies from naturally discharging excess body heat through sweat and perspiration. Instead, the heat builds up and raises their body's core temperature until it overwhelms their system. Farm workers are twenty times more likely to suffer heat stress and heat exhaustion than the average American worker, not to mention a wide range of severe heat-related illnesses, including heat cramps, heat rash, heat syncope, and heat stroke.

Symptoms of Heat Stress

Heat stress has an extremely detrimental effect on workers and productivity. It depletes their strength and ruins their concentration. Initial symptoms of heat stress include thirst, heavy sweating, irritability, shallow breathing, dizziness, confusion, and severe weakness or bodily fatigue. The loss of salt and moisture from the body can cause cramps and muscle spasms, and high temperatures can irritate the skin, causing clusters of pimples and blisters on the neck, chest, groin, and elbows. If left untreated, heat stress can cause light-headedness and fainting spells, a condition known as heat syncope.

In extreme cases, the person's internal temperature can rise so high they begin suffering from heat stroke. Their sweating mechanism fails and they lose their ability to regulate their body temperature altogether. Symptoms include hot, dry skin or profuse sweating, chills, throbbing headache, confusion, dizziness, slurred speech, and hallucinations. Without swift emergency treatment, heat stroke can cause permanent disability or even death. The illness impedes mental function so severely, victims may not even be aware of their own condition.

Preventing Heat Stress with Evaporative Coolers

Evaporative coolers are a powerful remedy to the dangers of heat stress because, unlike air conditioners, commercial grade evaporative coolers can effectively cool the outdoors. They work using the same cooling process your body uses: evaporation. Water on the surface of your skin (sweat) absorbs the excess heat from your body and carries at away as it evaporates. This is precisely what happens inside an evaporative cooler. Water is pumped up into a specialized, honeycomb cooling pad situated in front of a high-powered fan. The fan pulls warm air into the unit and through the pad, which causes the water to evaporate and absorb the heat in the air. The fan then blows cool air back out into the environment. Under the right conditions, evaporative air coolers can produce drastic results, lowering the ambient temperature by as much as 30°F.

Evaporative coolers are effective outdoors because they're extremely energy efficient. They have only two main working parts, a water pump and a fan, which means they use only a fraction of the electricity as an air conditioner, but can produce as much, if not more, cold air and cool larger areas.

 Evaporative CoolersOutdoor Air Conditioners
 Luma Comfort 220WPortacool PAC2K361SMaxxAir EC36D1MovinCool ClassicPlus26KwiKool KPO 12-43
Cooling Power (Cubic Feet per Minute)1650960097006805000
Coverage Area650 sq ft2500 sq ft2600 sq ft740 sq ft4800 sq ft

Portable evaporative coolers also provide farmers with a flexible array of cooling options. Depending on the type of fan installed in the unit, some, like the Port-a-Cool 46" Pro (Port-a-Cool PAC2K24HPVS) can spread air out over a wide area, in a cone extending out from the cooler, or concentrate it in a narrow beam that reaches straight out in front of the unit, like the Port-a-Cool Hurricane (Port-a-Cool PacHR3600). Each model is fully portable as well. They come installed with 4 caster wheels that make them easy to move and lock into place when the unit's ready to be activated. This means they can be moved to cool rows of workers as they're planting or harvesting, set up to cool work stations or collection points, or used to create cooling stations for workers to relax and recover from the heat periodically during the day. You can even combine different sized units to cover a wider area or to cool workers in different locations more effectively.

Treating Heat Stress

Evaporative Coolers Prevent Heat Stress Among Farm Workers
In a worst case scenario, evaporative coolers can also help farm workers recover from heat stress. Besides water, shade, and rest, evaporative coolers are a powerful cooling source that provides immediate and rapid cooling, the most crucial factor in preventing long term damage in workers suffering from the effects of heat stress, heat syncope, and heat stroke. The faster cooling happens, the more likely the patient is to survive, so in addition to placing them out of the sun and in front of an evaporative cooler, soak their clothes or wrap their head and neck in a damp towel to hasten the cooling process.

Best Conditions for Evaporative Cooling

The effectiveness of evaporative coolers varies depending on the environment. The rate of evaporation is governed by three factors: heat, air flow, and, most importantly, humidity. When humidity levels are low, the water molecules in the air are spread thin and have a hard time coming together to condense into liquid. Under these conditions, the air's ability to store water vapor is extremely high and evaporation happens quickly. As relative humidity begins to rise, however, the air becomes saturated and its capacity to store water vapor decreases. Evaporation slows, which decreases the amount of cold air an evaporative air cooler is capable of generating.

For this reason, evaporative coolers work best in arid conditions, where humidity levels are routinely low, primarily the West and Midwestern United States. The good news is that their effectiveness increases as temperatures rise. As air warms up, it expands and forces the water molecules to spread out over a wider area, which reduces water vapor density. This means that evaporative coolers are not only more effective during the summer months, when temperatures peak, they're also more effective during the hottest parts of the day, when they're needed most. If you're uncertain whether an evaporative cooler will work in your area, you can track humidity levels across the nation through by checking the US National Relative Humidity Map. If your area routinely experiences humidity levels above 60 percent, it's most likely not suitable to evaporative cooling. The temperature difference between the air coming out of the cooler and the air around it will be too small to provide relief.

Final Thoughts

With the right setup, evaporative coolers prevent heat stress among farm workers. Their low-cost cooling mechanism effectively reduces temperatures in outdoor areas so workers can cool off and continue working under high heat conditions. They're an adaptable tool that keeps workers healthy and productive, making them a valuable tool for farmers and their employees.

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