What you need to know about anti-fog safety glasses
Anti-fog measures are an essential part of safety eyewear safety.
Foggy lenses are something most eyeglass wearers have had to deal with over the past year during the COVID-19 pandemic. Those who have always needed PPE for their work have faced this problem for even longer. Eyewear fogging is a huge inconvenience and safety risk for these workers. In fact, fogged lenses are the number one reason workers remove or don’t wear safety glasses. Fortunately, there is a solution in the form of anti-fog safety goggles. Before diving into the science of anti-fog, it’s important to understand the cause of fog itself.
What causes fogging?
Fogged lenses can be caused by several factors. It is first crucial to understand what fog really is. Whatever its cause, fog is the result of water vapor that has condensed into fine droplets and collected on the lens. This is usually because the lens is cooler than the air around it. Why would that be? There are several potential reasons:
*Humidity. An abundance of warm, humid air is one of the most common causes of eyewear fogging up. Whether you’re working outdoors or in deliberately humid environments, warm air will collide with cooler goggles and cause them to fog up.
* Temperature change. Another common cause of lens fogging is drastic temperature changes. Moving from a cold place like a refrigerated unit or even just an indoor air conditioned place to a warmer place will cause the air to condense.
*Body heat. People working in hot environments or those exercising significant physical force may also experience fogged lenses due to the increased temperature of the air around them. Sweat can also fall on the glasses and be treated in the same way as fog.
*Face cover. Some face coverings, especially when worn incorrectly, cause hot breath to back up into the orbital cavity. This has become increasingly common as people wear masks to protect themselves from COVID-19. Although not a direct cause, washing anti-fog safety goggles can also increase the risk of fogging, as soap and water can rub off on some anti-fog coatings. For this reason, it is always important to follow the manufacturer’s instructions for proper care of anti-fog safety glasses. Each manufacturer will have different rules on how to clean their lenses depending on the type of anti-fog used as well as the material the goggles are made of. Following these guidelines is the best way to maintain the integrity and longevity of your anti-fog eyewear.
This article originally appeared in the April 1, 2021 issue of Occupational Health and Safety.