Anti-Fog Solutions to Keep Eyewear on Workers’ Faces and Not in their Hands
Many workers will instinctively remove their safety eyewear to see what is in front of them.
- By Mary Padron
- Oct 01, 2021
Lens fogging has always been a challenge in the industrial workforce, negatively impacting construction, machine shop, metal, law enforcement, food processing and other workers. However, mask-wearing during the pandemic has significantly multiplied this issue, as warm moist air is forced across the lens of safety eyewear. This undesirable situation ultimately leads to worker frustration, increased risks of vulnerability and injury and compliance issues.
When glasses fog, workers are caught in a Catch 22. If workers cannot see, what are they going to do? Many workers will instinctively remove their safety eyewear to see what is in front of them. This 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.
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.
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.
Preventing the Fogging Dilemma through Technology
Luckily, anti-fog technology has advanced to help safety pros deal with the fogging issues that often exasperate workers and interfere with their vision. Increasing in popularity are coatings that meet the demanding ANSI Z87.1 standard for anti-fog properties added for the U.S. in 2020 and the EN166K standard in Europe. There are several types of anti-fog chemicals and coatings. Many are temporary and erode over time, but there are premium coatings that are semi-permanent with a long shelf life. Anti-fog agents are available as creams, spray solutions and wipes, but the more resistant coatings are applied during the manufacturing process.
Non-Toxic Hydrophilic Coating. Hydrophilic anti-fog coatings have been developed from studies in nano science and nanotechnology. This type of coating has “water-loving” properties that absorb moisture and cause the individual water droplets to disperse evenly, forming a thin coating that releases the moisture at the edge of the lenses. Basically, it keeps water droplets from becoming large enough to be seen as fog. Water-based hydrophilic coatings are not soap- or solvent-based, so this non-toxic coating (another perk) does not wash off as easily as hydrophobic coatings.
Solvent-based Hydrophobic Coating. Hydrophobic anti-fog coatings are the opposite of hydrophilic coatings. These “water repelling,” soap-based coatings force water droplets to bead-up and slide off the surface. This type of coating is toxic during the application process, so it is not as environmentally friendly as a hydrophilic coating.
Longer Lifespan Solutions
When battling fogging and the impaired vision that comes with it, nothing is 100 percent permanent when it comes to the different anti-fog solutions. However, the premium semi-permanent hydrophilic coatings are better than before and offer longer lifespan solutions than the “economy” anti-fog alternatives.
Consult your manufacturer’s eyewear professional to make the proper determination on what your vision solution should be. Always make sure your selection of eyewear meets the ANSI Z87.1+ Standard. Concerned and product-savvy professionals at leading PPE manufacturers and suppliers work closely with ISEA and ANSI to bring about solutions that increase productivity and compliance. You can help diminish the fogging complaint by exploring the advancements made in anti-fog technology. By choosing promising anti-fog safety eyewear that is comfortable and stylish too, you will encourage workers to keep those goggles and glasses on their face and not in their hands.
This article originally appeared in the October 2021 issue of Occupational Health & Safety.