Page 74 - OHS, October 2021

PPE: VISION PROTECTION
instinctively remove their safety eyewear to see what is in front of them. ThThis leaves their eyes unprotected and at risk of injury from airborne particulate matter, dropped objects, chemical splash and more.
Thankfully, safety professionals can minimize fogging and prevent the incidents and injuries that result from it by specifying eyewear with anti-fog coatings.
Five Common Fogging Culprits
Why do lenses fog? Safety eyewear and prescription glasses fog up because of condensation, which is the process where water vapor becomes liquid. It is the opposite of evaporation, where liquid becomes a vapor. When warm air hits a cool surface, condensation can form. If the lenses of your safety glasses are cooler than the air around you, your lenses will fog up unless they have been treated with anti-fog coatings to help reduce the fogging.
Fogged lenses can result from several factors, but the five biggest culprits are:
■ Heat and humidity from the environment
■ Worker exertion
■ Face masks that don’t fit properly
■ Transitions between warm and cool
environments
■ Daily lens cleaning
1. Heat and humidity from our
environment often cause fogging on the outside surface of the lens. Hot and humid environments are a leading cause of lens fogging. Moisture in the air causes tiny droplets of water to collect on the outside surface of the lens—just like a glass of cold beer or water will “sweat” in the sun. Hot, humid summers, steamy boiler rooms and food processing plants are all examples of environments that can cause lens fogging.
2. Worker exertion often causes fogging on the inside surface of the lens. Even when the environment is cool, chances are the workers who wear eye protection have a job that involves physical exertion. When their body temperature increases, more sweat is produced, especially around the eyes and face. Instead of dissipating into the atmosphere, that moisture condenses and causes fogging on the inside surface of the lens, especially with sealed eyewear that restricts ventilation or when wearing the newer wraparound models that curve around the side of your eyes.
Safety professionals can minimize fogging and prevent the incidents and injuries that result from it by specifying eyewear with anti-fog coatings.
70 Occupational Health & Safety | OCTOBER 2021
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3. Face masks that do not fit properly.
Loose-fitting face masks cause fogging issues. Here is why: When you breathe inside a mask without a proper seal around the nose and mouth, hot air can build up inside the mask and escape through the top, coating your safety glasses with condensation. A properly fitting mask should direct your breath through the mask, not out the top or sides.
N95 respirators, often used by the medical community, usually have a tight seal. Many masks, such as disposable surgical masks, have a bendable nose wire that you can pinch and adjust to fit securely on your face. Plus, many reusable cloth face masks now feature a wire that contours to the bridge of the nose.
In addition to bendable nose wires that help reduce fogging, there are other face mask features that help with this challenge too, such as nose guards, adjustable ear loops and masks made with moisture- wicking fabrics. A secure face mask helps
prevent fogging and most importantly, helps shield droplets from talking, coughing and sneezing from reaching others if workers are not able to properly social distance.
4. Transitions between warm and cool environments. Going from an air- conditioned environment like your home, office, car or truck to the hot outdoors causes lens fogging, as does going from a warm environment to a cold environment. Workers who work simultaneously in hot and cold weather conditions know the frustrations and dangers of fogged eyewear.
5. Daily lens cleaning. While it is important to clean your eyewear of smudges, dirt and grime, coatings on eyewear, including anti-fog coatings, can be compromised from daily cleaning, which can rub off or erode the coating. Be sure to follow the manufacturer’s instructions for cleaning untreated and treated eyewear.
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