Environmental Engineering Reference
In-Depth Information
•.
The.beam.path.of.the.laser.must.be.located.and.secured.above.or.below.eye.
level.for.any.standing.or.seated.position.in.the.facility.
•.
All.windows,.doorways,.open.portals,.etc..of.an.enclosed.facility.should.be.
covered.or.restricted.to.reduce.any.escaping.laser.beams.below.appropriate.
ocular.Maximum.Permissible.Exposure.(MPE).level,.and.require.storage.or.
disabling.of.lasers.when.not.in.use.
In.addition,.there.are.speciic.controls.required.at.the.entryway.to.a.Class.IV.laser.
controlled.area..These.can.be.summarized.as.follows:
•.
All.personnel.entering.a.Class.IV.area.shall.be.adequately.trained.and.pro-
vided.with.proper.laser.protective.eyewear.
•.
All. personnel. shall. follow. all. applicable. administrative. and. procedural.
controls.
•.
All.Class.IV.area.and.entryway.controls.shall.allow.rapid.entrance.and.exit.
under.all.conditions.
•.
The.controlled.area.shall.have.a.clearly.marked.“Panic.Button”.(a.non-lockable.
disconnect.switch).that.allows.rapid.deactivation.of.the.laser.
Class.IV.areas.also.require.some.form.of.area.and.entryway.controls.such.as
•.
Non-defeatable.entryway.controls
•.
Defeatable.entryway.controls
•.
Procedural.entryway.controls
•.
Entryway.warning.systems
Administrative.and.procedural.controls.are.standard.operating.procedures,.align-
ment. procedures,. limitations. on. spectators,. and. protective. equipment.. Protective.
equipment.for.laser.safety.generally.means.eye.protection.in.the.form.of.goggles.or.
spectacles,.clothing,.barriers,.and.other.devices.designed.for.laser.protection.
Engineering.controls.are.normally.designed.and.built.into.the.laser.equipment.to.
provide.for.safety..In.most.instances,.these.are.included.on.the.equipment.(i.e.,.provided.
by. the. laser. manufacturer).. Some. of. these. controls. are. protective. housing,. master.
switch.control,.optical.viewing.system.safety,.beam.stop.or.attenuation,.laser.activa-
tion. warning. system,. service. access. panels,. protective. housing. interlock. require-
ments,.and.a.remote.interlock.connector.
Lasers.emit.beams.of.coherent.radiation.of.a.single.color.or.wavelength,.in.con-
trast.to.conventional.light.sources,.which.produce.incoherent.radiation.over.a.range.
of.wavelengths..The.laser.is.made.up.of.light.waves.that.are.nearly.parallel.to.each.
other,.all.traveling.in.the.same.direction..Atoms.are.pumped.to.a.higher.energy.state.
and. are. stimulated. to. de-excite. to. a. lower. energy. level,. and. in. the. process. release.
coherent.radiation.that.is.collimated.and.gives.off.radiation.to.produce.the.coherent.
laser.beam.
Because.the.laser.is.highly.collimated.(i.e.,.has.a.small.divergence.angle),.it.has.a.
high.energy.density.and.a.large.number.of.photons.in.a.narrow.beam..Direct.viewing.
of.the.laser.source.or.its.relections.should.be.avoided..The.work.area.should.contain.
