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Lasers are classified into four broad areas
depending on the potential for causing
biological damage.
When you see a laser, it should be labeled
with one of these four class designations:
·
Class I
- These lasers cannot emit laser radiation
at known hazard levels.
·
Class I.A.
- This is a special designation that applies
only to lasers that are "not intended for
viewing," such as a supermarket laser
scanner. The upper power limit of Class I.A.
is 4.0 mW.
·
Class II
- These are low-power visible lasers that
emit above Class I levels but at a radiant
power not above 1 mW. The concept is that
the human aversion reaction to bright light
will protect a person.
·
Class IIIA
- These are intermediate-power lasers (cw:
1-5 mW), which are hazardous only for
intrabeam viewing. Most pen-like pointing
lasers are in this class.
·
Class IIIB
- These are moderate-power lasers.
·
Class IV
- These are high-power lasers (cw: 500 mW,
pulsed: 10 J/cm2 or the diffuse
reflection limit), which are hazardous to
view under any condition (directly or
diffusely scattered), and are a potential
fire hazard and a skin hazard. Significant
controls are required of Class IV laser
facilities.
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