Environmental Engineering Reference
In-Depth Information
FIgure 23.9
Using.a.laser.as.a.level.
tABle 23.3
summary of Basic Biological hazards of light
Wavelengths
hazards to eyes
hazards to skin
Photobiological.Spectral.Domain
Eye.Effects
Skin.effects
Ultraviolet.C.(0.200-0.280.μm)
Photokeratitis
Erythema.(sunburn)
Skin.cancer
Ultraviolet.B.(0.280-315.μm)
Photokeratitis
Accelerated.skin.aging
Increased.pigmentation
Ultraviolet.A.(0.315-0.400.μm)
Photochemical.UV.cataract
Pigment.darkening
Skin.burn
Visible.(0.400-0.780.μm)
Photochemical.and.thermal.retinal.injury
Photosensitive.reactions
Skin.burn
Infrared.A.(0.780-1.400.μm)
Cataract,.retinal.burns
Skin.burn
Infrared.B.(1.400-3.00.μm)
Corneal.burn
Aqueous.lare.IR.cataract
Skin.burn
Infrared.C.(3.00-1000.μm)
Corneal.burn.only
Skin.burn
controls.during.operation.and.maintenance..Because.lasers.are.not.classiied.on.beam.
access.during.service,.most.Class.I.industrial.lasers.consist.of.a.higher.class.(high-
power).laser.enclosed.in.a.properly.interlocked.and.labeled.protective.enclosure..In.
some.cases,.the.enclosure.may.be.a.room.(walk-in.protective.housing).that.requires.a.
means.to.prevent.operation.when.operators.are.inside.the.room.
Class.IA.is.a.special.designation.based.on.a.1,000-second.exposure.and.applies.
only.to.lasers.that.are.not.intended.for.viewing,.such.as.a.supermarket.laser.scanner..
The.upper.power.limit.of.Class.IA.is.4.0.mW..The.emission.from.a.Class.IA.laser.is.
deined.such.that.the.emission.does.not.exceed.the.Class.I.limit.for.emission.duration.
of.1,000.seconds.
