There are a range of biases and perceptions about the performance of safety eyewear. Some say: If safety glasses are good protection then safety goggles must be better. While others think that safety goggles only protect from splashes and are ineffective at protecting from projectiles. The problem with these perceptions are just that – they are perceptions and are not founded in science or based on the results of laboratory testing and verification.
The starting point for the selection of any safety eyewear needs to be a proper hazard assessment. When selecting the appropriate safety glasses or safety goggles for workplace use, you must first perform a workplace hazard assessment. If eye and face workplace hazards are present, you must determine when, where and what type of eye and face protection is required. In completing the hazard assessment, you need to consider if the work or activity will create a risk of encountering projectiles that could come into contact with the eyes or face. Is there dust and debris that could be made airborne? Are there any chemicals being used that could be splashed or aerosolized and come in contact with the eyes? The decision to wear safety glasses or safety goggles, or some other safety eyewear needs to be made on the basis of a properly completed hazard assessment.
Let’s look at what protection is afforded by both safety glasses and safety goggles.
Safety glasses provide protection from dust, dirt, flying debris, and other projectiles created when work operations involve cutting, hammering, crushing, and other operations that may generate particulate. Safety eyewear is made from a of number of shatter-resistant lenses to protect the eyes from the impact of flying dust and debris. The available designs accommodate a range of lens thicknesses and materials to achieve the required impact resistance. The most common lens on the market today is made of Polycarbonate, a synthetic polymer resin. These lenses are light-weight, fog-resistant, and have a higher impact resistance. In Canada, approved safety eyewear must meet the performance standards set out in Canadian Standards Association CAN/CSAZ94.3 Industrial Eye and Face Protectors standard. Look for the CSA logo, and other relevant markings on the lens and frame or body of the safety eyewear.
Safety goggles provide the same protection from dust, dirt, debris, flying debris and other projectiles as safety glasses. In addition, because they have a tight-fitting seal to the face, safety goggles also provide protection from splashes and burns. Safety goggles protect from corrosives like acids, caustics, and hot liquids such as bitumen and abrasive blasting materials such as silica and metal slag. Some goggle designs also provide protection from laser radiation and electric arc flash.
The reason for the performance difference is that with safety glasses there is a gap between the protective eyewear and the face. This means that splashes, small particles, and reflect radiation or arc flash light energy can still be of concern when wearing safety glasses. Goggles make a tight-fitting seal to the face and prevent these harmful exposures from reaching the eye. When working in an environment where there are these potential exposures, safety goggles are the best choice. The tight seal of safety goggles may create initial wearer discomfort. Your Eyesafe optometrist can help you find this perfect fit.
Goggles come in three forms: direct vented, indirect vented and non-vented. Direct-vented goggles have front-facing vents that improve air circulation and reduce fogging. Direct vented goggles allow for air flow directly into the goggle. The vented openings are designed to exclude particles that are 1.5 millimeters in diameter or greater. Direct vented goggles work well where projectile impact is a hazard. Direct vented goggles do not provide adequate protection from splashes of chemicals and toxic liquids to splash up into the face and eyes.
Indirect vented goggles have covered vents and provide protection from splash entry by liquids. Air flow through the covered vents is restricted by the vent cover. The covered vented ensures that there is no direct straight-line passage from the exterior to the interior of the goggle preventing a liquid splash from entering the goggle. There is reduced air circulation in indirect vented goggles and this can lead to an increased likelihood of fogging.
Non-vented goggles have no venting of any kind and offer protection against the passage of dust, mist, liquid and vapours. Non-vented goggles provide the best protection from all types of hazards including exposure to chemical vapour. Non-vented goggles have no intentional air flow and are the most likely goggle type to have problems with fogging. It is important to note that non-vented goggles are not gas-proof and if gas-proof protection is required a more elaborate type of PPE will be required such as a gas-tight suit.
Goggles need to be carefully selected considering the performance characteristics of each goggle type and the inherent performance limitations of each. Safety goggles can in fact create hazards of their own, such as fogging in hot and or humid conditions that may limit vision. This can create a risk of slips trips and falls or being struck because of reduced vision. Anti-fogging coating can help reduce this limitation. Safety goggles can also be purchased with a prescription lens to avoid the need for contact lens use by people who normally wear prescription glasses. A variety of lens tints are also available for UV protection if goggle use outdoors is required.
Regardless of the workplace conditions safety eyewear is an important part of many employees’ everyday workwear. We know that employees who are properly fitted and trained to correctly wear safety glasses and safety goggles can get a comfortable fit and experience user compliance. Consistent use of safety glasses and safety goggles, when the hazards dictate can provide the best protection against eye injury at work. With time and persistence, all employees can wear safety eyewear comfortably and in compliance with work demands.
Glyn Jones is a partner at EHS Partnerships Ltd. in Calgary. He is a consulting occupational health and safety professional with more than 30 years of experience. He is a regular safety conference speaker in Canada and he provides program design and instructional support to the University of New Brunswick’s OHS certificate and diploma programs.