Arc eye is a common risk when welding, and plasma cutting is no different (if not worse!). Plasma cutting is a machining process where an ionized gas (plasma) is concentrated into a small jet to cut conductive metals.
The plasma stream reaches temperatures of up to 20,000C or 36,000F and will emit intense radiation across the EM spectrum, with most focused between UV to infrared.
It is incredibly dangerous to directly observe EM radiation of that intensity. Blue light emitted during an operation can permanently damage your retinas without you even knowing it before it’s too late. You’ll definitely need protection.
Ways to Protect Your Eyes While Using Plasma Cutting
1. Welding helmet
If you’re plasma cutting, chances are you have some experience welding too. Is there PPE overlap? Yes. A shade 5 welding helmet is good for most plasma cutting jobs up to 40 amps. However, the darker the better, and if you need to be OSHA compliant then shade 8 should be your minimum.
Full-head protection from a helmet is as good as you’ll get. In the interest of safety, a plasma cutting helmet should be your first choice.
2. Cutting lens and shade 5 glasses
For some jobs, you might find safety glasses with yellow lenses good enough. Yellow lenses will block harmful blue light, but these would be an aesthetics-over-safety option and we recommend you use higher shade gear.
Similarly, shade 5 glasses can protect your eyes during most of the work on a lower amp range. They are stylish and comfortable while still achieving good functionality.
3. Face shields
Face shields are a comfortable middle-ground between glasses/goggles and full helmets. You can get a shield for any shade level, which makes them very versatile.
4. Welding/torch goggles
Shade 5 or above goggles are great protection for the average plasma cutting operation. Most will enclose the eyes like pictured above, and some feature flip-up lenses for added shading. Not as comfortable as a pair of safety glasses, but they’ll do the job well.
The same in functionality but a very different look, rectangular torch goggles come with a flip-up shield; letting you quickly switch from work to inspection. They also offer greater visibility, which is important when working with 36,000F arcs.
5. OTG safety glasses
OTG safety glasses are coated in UV and IR protective material for 1.7 shade. Perhaps most important of all: they can fit your glasses! Precision eyesight is important for precision work.
It’s not advisable you use OTG safety glasses for any prolonged or high-current plasma cutting work as they don’t have the minimum shade specified by ANSI and the American Welding Society.
Minimum Shade Specifications for Plasma Cutting
|Arc Current (Amps)||Minimum Shade Number||Suggested Shade|
Table 1 – The numbers in this table are according to ANSI Z49.1:2005. Working below the minimum shade number brings risk of permanent eye damage.
Things to Consider When Choosing Eye Protection for Plasma Cutting
Finding a personal balance between good protection and visibility can be a hassle. Fortunately, some eye protective gear features auto-shading technology; becoming more or less opaque depending on the cutter amperage. These will be more expensive, and you’ll likely need to spend extra on batteries.
2. Fashion and functionality
We’re all guilty of preferring aesthetics over safety one way or another. The selection of PPE we’ve outlined above offer a good range of protection and pleasing design.
Safety goggles look nice, but they definitely aren’t OSHA compliant. If you need to wear your glasses regardless of the job, consider the OTG safety glasses.
3. Adjustable fit
Other than safety glasses, you’ll find most of the equipment we’ve listed has elastic or otherwise adjustable fitting. It’s important your helmet isn’t falling off your head.
4. Lens material
The lenses in your protective eye//headwear are perhaps the most important part. The heavy-duty glass is tinted to oppose UV and IR light, protecting your eyes from permanent damage.
The tint can be darker or lighter, denominated in shade numbers, depending on the cutter amperage. The higher the amperage, the darker the lens (corresponding to bigger shade numbers).
Keep an eye out for the shade numbers when looking for plasma cutting PPE. Too low and you risk damaging your eyes!
1. Can I get arc eye from plasma cutting?
Ans. Yes, a plasma arc can burn your eyelids. Plasma arcs emit intense levels of radiation through the UV to IR range of visible light.
What’s more important however, is not knowing your eyes are damaged. Intense blue light radiation from plasma cutting can seriously damage your retinas without you being aware until the damage is irreversible.
2. How does a plasma cutter operate?
Ans. Plasma forms when gas particles lose an electron, ionizing the gas. Gas is ionized by passing a strong electric current through it. Plasma cutters work by passing pressurized gas through a nozzle where an arc ionizes it.
This plasma can travel at hypersonic speeds and reach up to 36,000°F.
3. How do I know what shade to use?
Ans. Check the recommended shade against the cutter amperage you intend to use. Another rule of thumb to remember is to start with the darkest shade you can only just see anything in and go down in shade numbers until you can see the workspace enough to start machining.