University policy on eye protection requires students, faculty, staff, and visitors in laboratories wear eye protective devices during any experiment or laboratory procedure (regardless of anticipated eye hazards). The type of safety device required depends on the nature of the hazard and the frequency with which the wearer encounters it. There are three basic types of eye and face protection that meet the majority of University laboratory requirements: safety glasses with side shields, goggles, and face shields. Each of these meets basic eye protection standards for frontal exposure to flying particles. Laboratory supervisors must determine the appropriate level of eye protection for particular tasks, and enforce eye protection rules.

Safety Glasses

Ordinary prescription glasses do not provide adequate protection from injury to the eyes. Adequate eye protection requires the use of hardened-glass or plastic safety spectacles with side shields (Figure 5.1). Safety glasses used in the laboratory must comply with the Standard for Occupational and Educational Eye and Face Protection (Z87.1) established by the American National Standards Institute. This standard specifies a minimum lens thickness of 3 mm, impact resistance requirements, passage of a flammability test, and lens-retaining frames.

Three important dimensions for fit and comfort include temple length, nose bridge width, and lens diameter. Safety spectacles with side shields, bendable temples, and universal nose bridges are available in several lens diameters. Prescription safety spectacles are recommended for employees wearing glasses. Contact EHS for information on obtaining prescription safety glasses. Do not wear photogrey (transition) lenses indoors in laboratory environments, because the percentage of light transmitted under normal light conditions is below ANSI standards. Wear chemical splash goggles or full-face shields (Figure 5.2) when significant liquid splash hazards exist. The side shields on safety glasses offer some protection from objects approaching from the side, but do not provide adequate splash protection.

Goggles

Goggles provide a tighter face seal than safety glasses, and are not for general laboratory use. Wear them when there is a hazard from splashing chemicals or flying particles. For example, wear goggles when using glassware under reduced or elevated pressure, or using glass apparatus in combustion or other high temperature operations. Impact-protection goggles have perforated sides to provide ventilation and reduce fogging of the lens, but do not offer full protection against chemical splashes. Usechemical goggles with splash-proof sides for protection from harmful chemical splash.

There are also specific goggles and masks for glassblowing and intense light sources such as welding or lasers. For questions about laser safety, including eye protection, consult the UNC Laser Safety Manual or the Radiation Safety Manual or contact EHS at 919-962-5507.

Face Shields

Goggles or safety glasses alone do not meet ANSI standards for protection to the face and neck. When you need greater protection from flying particles and harmful liquids, wear full-face shields that protect the face and throat (Figure 5.2). For full protection, always wear a pair of safety glasses or goggles when wearing a face shield. A metal-framed “nitrometer” mask offers greater protection for the head and throat from hazards such as flying glass or other light fragments. Consider using a face shield or mask when operating a vacuum system (which may implode), or conducting a reaction with the potential for mild explosions. Always use a UV-blocking face shield when working with transilluminators or other devices that produce ultraviolet radiation.

Cost, Care and Reclamation

The University is committed to a policy of providing eye and face protection devices without cost to students, employees and visitors. Each department is responsible for funding its eye and face protection program. The employee and/or student are responsible for scheduling and payment for eye examinations to obtain safety glasses prescriptions. Eye protective devices issued to employees, students and visitors remain the property of the University. Persons issued eye protective devices return it when the use of the device is no longer necessary. For students, this is normally at the end of each semester, and for employees upon termination of employment or change in duties where eye protection is no longer required. The department shall determine the disposition of prescription glasses. You may replace eye protective devices damaged during normal wear and use without charge at the discretion of the department head or designated administrative officer. Replacement of lost or stolen devices is the responsibility of the employee or student issued the equipment.

Eye protective devices are personal items, issued for the exclusive use of each individual. Clean with soap and water and store in a clean, protected area. Thoroughly clean and disinfect all eye protective devices before issuing to another person.

Contact Lenses

The National Society to Prevent Blindness points out that contact lenses do not provide adequate eye protection for hazardous operations and must be worn in conjunction with approved safety eyewear. The University permits the wearing of contact lenses in laboratories, only if the wearer has other forms of eye protection mentioned above. Earlier guidance recommended against wearing of contact lenses in laboratories, due to concerns about lenses trapping chemicals. However, several years of subsequent studies have shown that contact lenses do not create an additional hazard; in fact, the improved visual acuity from contact lenses might help prevent accidents, compared to no corrective lenses.