This is a question that is asked quite often, as most people that wear safety goggles, ski goggles, airsoft goggles, paintball masks, and more have experienced fog building on the eyewear. I have experienced this first-hand, and found it to be a challenging problem for a long time, at least until I invented the ExFog, which started as my own personal remedy and gained a lot of popularity!
The answer is fairly straightforward…My safety goggles fog because of four main factors (generally).
- Air Flow – Breathability of the Goggle
- Temperature Differences between the inside of the lens, and the outside air.
- Humidity
- Cleanliness of the goggle lens
Generally speaking, but not always, goggle fog occurs because the safety eyewear isn’t “breathing”. As my face heats up, and as I breath, the enclosed area is collecting humidity, and heat. The more that the goggles have air ventilation, the more likely that heat and humidity will move through those vents. When there isn’t enough air flow, such as wind or products like micro-fans or the ExFog Anti-fog system, the air can not be pushed through and out. The fog particles will collect on the lens as it tries to escape, creating fog.
Air Flow, then, is certainly one of the critical factors relating to why my goggles fog. For many environments, a person is restricted by the gaps or air-holes they can have in safety goggles, and unfortunately, outside of the ExFog, there just aren’t many custom products that are designed to increase air-flow without creating unsafe and large openings in the goggles themselves. Air flow, or lack of it, is likely the most key factor as it relates to Goggle Fog. When looking at common glasses, as a great example, they rarely fog. Why? Because there are no seals that trap the air and humidity.
Temperature Differences between the inside and outside then, can most certainly be attributed to why my goggles fog as well, such as in the case of downhill skiing, mountain climbing/hiking and other cold weather environments. Think of this example: You have a cold glass of ice water, sitting outside on a very hot day. What happens? It collects a large amount of moisture on the outside of the glass where the heat is (in the form of condensation). Now, imagine the “hot day” representing the air between your face and the lens. The lens of the goggle is the glass, and the cold ice water represents your current environment outside. Notice how that humidity in the goggle will want to stick to the lens as it begins to condense as it is attracted to that colder outside temperature? This is why warm cars can get foggy windows, etc. With no air to push the humidity out, the fog will collect on the goggle.
Humidity, as mentioned in the above examples is a major part of fog. If I effectively didn’t sweat or breath, humidity would be decreased and Goggle Fog would occur less frequently. Unfortunately, there aren’t really remedies for that. Some people produce more body heat and humidity, and as a result, create more fog.
Cleanliness, then is one of the final factors as to why my Goggles Fog. I am not sure that cleanliness was the most appropriate word, because it actually should be the “smoothness, or slickness” of the goggle lens. Basically, fog needs to stick on something to fog up the goggles. If the lens isn’t absolutely the smooth, then fog will stick. There are a lot of “thermal lenses” in the market that claim to prevent fog. Some do work better than others, but often times the treatment will wear off, or the lenses will just plain get dirty. Without them being absolutely clean, fog can and will attach to the lens of the safety goggle, causing loss of vision and potential safety issues.
We created the ExFog for active people, who need a permanent solution to Fog, and invite you to give us a try. Feel free to navigate our blog for other remedies, and information that may also help!
I hope you found this informational, yet not overly technical. My goal was to have a sound piece of information that help people identify why their goggles fog without also being an introduction to physics.
As a note, we have also started an ExFog® group on Facebook – Would love for you to join, follow and share if you would like to see this new patent pending innovation come to market!
There is always room for other good information, so don’t hesitate to comment or share any suggestions you may have!!!
