What you need to know about anti-fog safety glasses
Anti-fog measures are essential to ensure the safety of safety glasses.
Misty lenses are something most eyeglass wearers have dealt with in the past year during the COVID-19 pandemic. Those who have always needed PPE for their work have faced this problem for even longer. Fogging of glasses is a huge inconvenience and a risk to the safety of these workers. In fact, lens fogging is the number one reason workers remove or don’t wear safety glasses. Fortunately, there is a solution in the form of anti-fog safety glasses. Before delving into the science of anti-fog, it’s important to understand the cause of the fog itself.
What are the causes of fogging?
Fogging of lenses can be caused by several factors. First, it is crucial to understand what fog really is. Whatever the 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 hot, humid air is one of the most common causes of foggy glasses. Whether you are working outdoors or in deliberately humid environments, hot air will collide with colder glasses and cause fogging.
* Temperature change. Another common cause of foggy lenses is drastic temperature changes. Moving from a cold location like a refrigerated unit or even just an air-conditioned indoor location to a warmer location will cause the air to condense.
* Body heat. People working in hot environments or those who exert great physical strength may also have to deal with lens fogging due to the increase in the temperature of the air around them by their body. Sweat can also fall on glasses and be treated the same as fog.
* Face cover. Some face coverings, especially when worn incorrectly, bring hot breath up into the orbital cavity. This has become more and more common as people wear masks to protect themselves from COVID-19. While this is not a direct cause, washing anti-fog safety glasses can also increase the risk of fogging, as soap and water can bleed some anti-fog coatings. For this reason, it is always important to follow the manufacturer’s instructions for proper maintenance 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 of the glasses. Following these guidelines is the best way to maintain the integrity and longevity of your fog glasses.
This article originally appeared in the April 1, 2021 issue of Occupational Health and Safety.