TM-022 PN 35934
Rev 05/12/98
4
SAFETY
Safety Precautions Must Be Observed By All Personnel Working
Near or Around Ultraviolet (UV) Light
UV Terminology
The portion of the Electromagnetic spectrum which falls between x-rays and visible light
is called Ultraviolet or UV. Ultraviolet (UV) radiation can be classified into three
categories: UVC, UVB, and UVA. UVC is for the wavelengths below 280 nm, UVB is
for the wavelengths between 280-315 nm, and UVA is for the wavelengths between
315-380 nm.
Exposure Hazards
Exposure to UV light, even for short periods of time, can be hazardous. The danger
depends upon the exposure time, the intensity of the light, the wavelength, and the
individual’s sensitivity to UV. UV-B and UV-C can be considered the most hazardous to
the skin, causing such effects as sunburn. Ultraviolet light is considered to be
hazardous to the eyes, this is why eye protection is important when working around UV
light.
Ozone is a form of oxygen. Interaction of ultraviolet light below 220 nm with oxygen in
the surrounding air produces ozone, which is a powerful, toxic agent. It has a
characteristic pungent odor to which most people are quite sensitive (people can
typically detect concentrations of several parts per million). At high concentrations, it
can cause discomfort, or at sufficiently high levels, be dangerous. The EC series of
lamps do not produce ozone as they are made out of a special material for the lamp’s
envelope called ozone-free quartz. Ozone is suppressed in this case, even if it is
generated by the arc.
Safety Guidelines
The National Institute for Occupational Safety and Health (NIOSH) recommends that
exposure to UV energy be controlled and limited in the work place. Recommended
maximum exposures are available, but do not apply to photosensitive individuals.
The total intensity from 320 to 400 nm hitting unprotected skin or eyes should not
exceed
1 mW/cm² for periods longer than 1000 seconds. For shorter exposure times, the total
radiant energy shall not exceed 1000 mW
sec/cm².