Safety Concerns

Un-cured UV materials should be treated with care just like any industrial chemical, refer to the MSDS (material safety data sheets) provided by the UV material supplier for specific guidance on the handling, storage and disposal of the actual UV material being used. Many un-cured UV materials can irritate the skin and mucous membranes around the eye and nose areas. During and immediately after the handling of the un-cured UV material, keep hands away from eyes, nose, and mouth. Always wear protective latex gloves when handling un-cured UV material and thoroughly wash any residue from the skin with soap and water prior to eating, going to the bathroom or smoking. Material left on the skin for a period of time can cause an itching sensation and ultimately a rash. Once cured, the UV material can be handled normally without any concerns.

Although UV light occurs naturally all around us, especially on a sunny day, the intensity of UV light emitted by a UV lamp is much greater than that found outdoors. UV lamp system users routinely incorporate shielding to protect the operator from this high intensity UV light. Light shields should be properly designed to prevent the operator, when in a normal position, from looking directly at the bulb or the area where the focused light from the lamp strikes the substrate being cured, known as the cure zone. The shielding should not let any light escape its scope. Secondary reflections contain a lower level of UV light due to the poor UV reflectivity of most materials, but they still need to be controlled. The operator can be protected from this by wearing UV rated safety glasses supplied by the manufacturers of the UV curing system. A glow of light from a light shield is considered a safe level. In cases, where it is not feasible to reach this level of light attenuation, proper protection of eyes and skin is necessary, this includes UV blocking glasses, gloves, long sleeve shirts, and possibly face protection. Never look directly at the bulb or into the cure zone. UV light has well-documented effects on unprotected skin and eyes. Sunburn is caused when the skin absorbs too much UV light. The unshielded light from a UV lamp can cause the same kind of burns. Direct light absorbed from a UV lamp can cause "snow blindness" or "welders flash" in the cornea of the eyes. UV burns to the skin and cornea, though normally painful, can completely heal in a few days time.

Ozone is a type of oxygen molecule, created when a normal 2 atom oxygen is broken apart by high energy and then recombines into the 3 atom ozone molecule. In nature, UV light from the sun and the electrical discharge of a lightning bolt both create ozone. Oxygen absorbs UV strongly in the 185nm wavelength. During lamp start up, the cold quartz tube transmits 185nm UV. As the quartz heats up to operating temperature, the transmission curve of the quartz shifts towards the longer wavelengths and 185nm light is no longer able to pass through the quartz. For this reason, ozone is generated by UV lamps mostly during start up, but also during the running time. In the concentrations found in UV curing systems, ozone can possibly irritate the mucous membranes of the eyes, nose, and throat. Most UV systems are designed to discharge exhaust air outside the plant to eliminate this possibility.