Have you ever wondered if the safety glasses you wear every time you mix chemicals or work around the house protect you? Knowing what are safety glasses made of will give you an idea of how well this personal protective device can keep you safe.
Professionals know how crucial safety glasses are in keeping them safe. The same is true for ordinary persons creating different solutions with various agents. The glasses’ protective capabilities are a function of their material composition.
In general, safety glasses have frames made of thermoplastic polymer resin or high-tensile strength nylon. Meanwhile, their lenses are often polycarbonate or Trivex, with a small number of products having glass as a material. Read on to learn more.
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What are Safety Glasses
In their simplest definition, safety glasses are pieces of eyewear meant to protect the wearer against injuries or harm to the eyes.
They are a form of personal protective equipment, allowing the person to shield his eyes from foreign debris, particles, or any substance that can lead to injury, inflammation, or irritation.
If you come to think of it, safety glasses are not that different from your ordinary reading glasses or swimming goggles. These types of eyewear also protect your eyes.
Well, not exactly. You see, safety glasses must pass certain standards before any product can receive a safety glass classification. These glasses must conform to the strict requirements of the Occupational Safety and Health Administration (OSHA) and the American National Standards Institute (ANSI).
In general, the eyewear must be impact-resistant and lightweight, giving the wearer the sensation of not wearing any safety glasses at all.
What are the OSHA Standards for Safety Glasses
OSHA requires safety glasses to protect the wearer against five general forms of eye hazards.
Chemicals
Irreversible tissue damage can occur if caustic substances reach mucus membranes or the eye itself. Chemical contact can be fumes, vapors, mists, and splashes that can occur when plating, degreasing, and handling chemicals and acids.
Dust
When working in dusty environments, the safety glasses must come with a face lining to prevent the entry of dust particles into the eyes. If there are no lined safety glasses available, one must use safety goggles.
Heat
Hot sparks, molten metal, and high temperatures can lead to ocular soft tissue injuries. Safety glasses must withstand high temperatures.
Impact
Falling objects, sand, particles, fragments, and large chips can hurt the eye, causing contusions, abrasions, and punctures. Woodworking, machining, sawing, drilling, riveting, sanding, chipping, grinding, and masonry work are all potential sources of impact-related eye injuries.
Welding and Metal Cutting
Brazing, soldering, cutting, and welding activities produce intense radiant energy that damages the eyes. Flying sparks, slag chips, and metal spatter can also injure the eyes. Welders and other people working in these industries must use safety glasses with the correct filter shade number.
In addition, there are some over-glasses safety glasses that you can use even if you are wearing prescription glasses.
What are the Standards for Safety Glasses According to ANSI
ANSI has high standards for safety glasses. The organization subjects safety glasses to a series of tests, including shooting the lens with a high-speed (over 100 MPH) steel ball. The lens must stay intact even when the steel ball impacts at 170 MPH.
Safety glasses that pass the 170-MPH steel ball impact test receive the Z87.1 certification. The ANSI seal is your guarantee that the safety glasses you are wearing can protect your eyes in high-intensity and high-velocity situations.
What are Safety Glasses Made of
1. What are Safety Glass Frames Made of
The main difference between safety glasses and other types of eyewear is their material construction. Safety glasses material almost always features lightweight but exceptionally strong thermoplastics or similar substances.
Safety glasses must have frame materials that are sturdy yet lightweight. They must not break easily. More importantly, the frame must never be uncomfortable. It should not make your head feel like getting squeezed in a vice grip.
Most safety glasses feature shatter-resistant frames made of transparent thermoplastic polymer resin, such as Grilamid TR. This plastic material has exceptional flex fatigue strength, weather resistance, and impact resistance.
It also has low flammability and superior protection against stress cracking, extreme temperatures, and chemicals. It is not surprising many high-end safety glasses use this revolutionary plastic material for their frames.
Some manufacturers prefer to go old-school, using high-tensile strength nylon for their safety glasses’ frames. It is lightweight, too.
Whatever material the safety glass frame features, it must stand up to high-impact forces. It should also do well in corrosion and flammability tests. After all, you do not want to use eyewear that catches fire.
2. What are Safety Glass Lenses Made of
It is easy to see why the majority of lenses for safety glasses feature polycarbonate. This thermoplastic has a glass-like optical performance, allowing it to transmit light to the eyes. It is almost similar to not wearing glasses at all.
Its main advantage over glass is that polycarbonate can withstand greater impact forces before cracking. Even if it breaks, it does not produce sharp, tissue injury-causing splinters. It is also more robust than ordinary plastic materials.
Manufacturers also love working with polycarbonate because it does not require heat to reform. It is also pliable, allowing technicians to make it at room temperature without breaking or cracking.
Making polycarbonate lenses for safety glasses requires melting polycarbonate pellets before injecting them into lens molds. The melted polycarbonate undergoes high-pressure compression before being rapidly cooled to form the lens.
Polycarbonate lenses have been ruling the safety glasses industry since the 1970s. With almost half a century of trusted and proven performance under their belt, it is unimaginable that another material can take its throne.
That is until 2001, when PPG Industries introduced Trivex lenses.
Trivex lenses offer the same advantages of polycarbonate over glass lenses. However, this material upped the ante by making the lens more scratch-resistant and with superior optical clarity. Trivex lenses also have photochromic capabilities (think eyeglasses that are clear indoors and dark outdoors).
Contractors working with intense bright lights will love Trivex lenses because they automatically darken to protect the eyes from potential light-induced blindness.
Mind you, polycarbonate manufacturers are responding to the Trivex challenge. Some high-end polycarbonate safety glasses today also come with photochromic capabilities.
Another difference between polycarbonate and Trivex lenses is their manufacturing process. While polycarbonate lenses require injection molding, Trivex lenses undergo the same cast molding process as ordinary plastic lenses.
Are There Safety Glasses Made of Glass
You might find it unbelievable, but there are safety glasses made of glass. These pieces of protective eyewear offer better scratch-resistance than ordinary plastic lenses.
Unfortunately, you cannot expect these glasses to be as impact-resistant as polycarbonate or Trivex. Still, they make excellent options for ordinary people who prefer glass over thermoplastic materials.
Another concern you may have about these safety glasses is that they might not have the correct ANSI Z87.1 certification. Can you imagine glass standing up to a 170-MPH speeding steel ball impacting the surface?
Conclusion
What are safety glasses made of? The great majority of safety glasses we have on the market today feature high-quality polycarbonate and Trivex. These materials are robust, flexible, and offer exceptional protection against heat, impact, dust, and chemical-related eye injuries.
If you want to be sure about your safety glasses’ protective capabilities, you might want to check if they adhere to OSHA guidelines. Ideally, you will need safety glasses with ANSI’s Z87.1 certification. Your life will be better knowing you get to keep your eyes’ integrity.
Our PPE expert, Daniel Rocha, has been working in the industry for 23 years. He provides guidance to our content editor and writers so they may provide well-informed suggestions and tips for machinery and equipment.