What type of lens material do you need for your safety glasses?

Safety glasses have come a long way since the days when P. Johnson invented them in the 19th century. In those days, the only protection they could offer was against bright light. Today’s products are lightweight, snug, and capable of protecting you from a huge array of hazards. Whether you need them to resist chemical splash, dust, or light, there’s a fabrication just for you. They even look stylish enough to wear all day.

Precision Protection

Modern safety glasses can be broadly divided into three categories: full vision goggles, safety spectacles, and overspecs. Each category comes with a range of impressive specifications, so today’s employers can refine their protection with absolute precision. Most contemporary safety glasses lenses are constructed from polycarbonate; a material that’s stronger than plastic, lighter than glass, and more resistant to dust and chemical splash.

These miracle lenses resist impact exceptionally well, so plastic has been relegated to the past. Brand titans all over the world are constantly developing new fabrications that are promptly trademarked and patented. These days, your lenses can be made from:

• Trivex—a light, powerful material that offers 100% protection against UV light. It refracts exceptionally well and can even sharpen direct and peripheral vision.
• CR-39—a light, high index plastic that creates thin, UV-resistant lenses.
• Crown Glass: A heavy, low-cost alternative that offers exceptional clarity.
• Tribid: An impact-resistant material that improves on polycarbonate’s Abbe value.
• Plutonite: A purified carbonate with exceptional clarity and photochromic protection.

​Safety glasses can achieve a refractive index of 1,498 to 1.74, but the way they disperse wavelengths is equally important. This is ranked by Abbe value, which gives you an idea of chromatic aberration and peripheral clarity. Crown glass has an abbe value of 59, while polycarbonate has an Abbe value of 30. It’s easy to get lost in a world with so many options, but fortunately, OSHA has developed a comprehensive guide.

OSHA and ANSI Protection Safety Glasses

OSHA cites safety lens requirements by hazard, with flying particles, molten metal, caustic liquids, light radiation, and chemical gases being the most important. It also formulates regulations by industry and requires employers to provide the best protection possible for each risk your employees face. Radiant energy lenses must achieve a specified arc current, electrode size, and minimum protective shade, for example.

Gas tungsten arc welding glasses must have an arc current of less than 60 and a minimum protective shade of eight, whereas air carbon products require an arc current of 500 at most. OSHA also requires plate thickness minimums. Lenses must have clip-on or slide-on side protection. It isn’t the only regulatory body operating in this regulatory niche. The ANSI’s Z87 defines the testing, maintenance, and selection of all safety lenses. To make your selection process easier, ANSI has created a code that represents hazard types.
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• D3: Splashes and droplets
• D4: Dust
• D5: Fine dust
• W: Welding filters with a shade number of 1.3 to 1.4
• U: A UV filter of two to six
• R: Infra-red filtration of 1,3 to 10
• L: Visible light
• V: Variable Tint
• S: Special purpose
• H: Head size.

​ANSI protection safety glasses are also held to a stiff list of standards. Safety glasses codes are thus a color-by-numbers affair that requires little of their buyers. Simply list the hazards, then find the code that corresponds with them. Shading protects against light, while plastic retainer lenses protect against filter lens breakage. Glass-containing fillers are often used for their UV protection, but an outer polycarbonate plastic can defend against scratches and impact. Where oxygen cutting is done, the plate thickness of lenses must rise to 25 to 150.

Lens Treatments for Z87 Safety Glasses

Every Z87 safety glasses material has its weaknesses and strengths, but they can be mitigated by a good lens treatment. Protective coatings can add to impact resistance, reflectiveness, and UV resistance. They won’t protect against a flying nail, but they can add a little extra resistance to ANSI prescription safety glasses.

Anti-fog and anti-scratch coatings can prevent construction workers and welders from losing visibility at critical moments, so they’re more important than you might think. Polarized lenses also bring important features to safety lenses, minimizing glare while refracting direct light.

Is Polycarbonate Redundant?

With so many innovations in the industry, it’s easy to wonder if polycarbonate has been rendered obsolete. It’s a remarkably attractive option given its low price and excellent specifications, but will it protect your staff as well as its rivals?

Polycarbonate is still used for the vast majority of PPE equipment. It’s often used to make bulletproof glass, so its impact resistance is tough to beat. Add a hardened treatment, and you have one of the highest levels of protection on the market.
PC lenses are thin and light, with an excellent Abbe value despite their low chromatic aberration. They offer robust impact resistance in a material that's easy to source. Add UV protection and you have an economical range of balanced qualities.

Every day, 2, 000 people experience an eye injury at work that requires medical care. Most of them are caused by flying debris, so they’re entirely preventable. These accidents represent weeks of absenteeism at a rate of $1,100 per employee. That comes with serious opportunity costs and can lose you important clients, so your choice of safety glasses has an important impact on your productivity and profits.

Protecting staff needn’t entail a steep learning curve, though. OSHA and ANSI have provided all the guidance you need to provide the best level of safety. Every year brings a list of new fabrication innovations, so your power to prevent health crises grows with each passing month. Tomorrow might bring the perfect safety lens material, but today's are surprisingly effective.

Bridge Safety Vision connects you with Walmart vision centers so that you can, at last, gain the best protection in the industry from your own neighborhood. In just five minutes, you can submit prescriptions via our convenient voucher-based digital payment card system.  It's time to experience the best for less.