Environmental Engineering Reference
In-Depth Information
blower,.aside.from.portability,.is.minimal.set-up.time..Another.way.to.reduce.heat.
stress.is.to.increase.airlow.or.convection.using.fans,.etc..in.the.work.area.(as.long.
as. the. air. temperature. is. less. than. the. worker's. skin. temperature).. Changes. in. air.
speed.can.help.workers.stay.cooler.by.increasing.both.the.convective.heat.exchange.
(the exchange. between. the. skin. surface. and. the. surrounding. air). and. the. rate. of.
evaporation..Because.this.method.does.not.actually.cool.the.air,.any.increase.in.air.
speed.must.impact.the.worker.directly.to.be.effective.
Heat. conduction. methods. include. insulating. the. hot. surface. that. generates. the.
heat. and. changing. the. surface. itself.. Simple. engineering. controls,. such. as. shields,.
can.be.used.to.reduce.radiant.heat.(i.e.,.heat.coming.from.hot.surfaces.within.the.
worker's.line.of.sight)..Surfaces.that.exceed.95°F.are.sources.of.infrared.radiation.
that. can. add. to. the. worker's. heat. load.. Flat. black. surfaces. absorb. heat. more. than.
smooth,. polished. ones.. Having. cooler. surfaces. surrounding. the. worker. assists. in.
cooling.because.the.worker's.body.radiates.heat.toward.those.surfaces..With.some.
sources.of.heat.radiation,.such.as.heating.pipes,.it.is.possible.to.use.both.insulation.
and.surface.modiications.to.achieve.a.substantial.reduction.in.radiant.heat..Instead.
of. reducing. heat. radiation. from. the. source,. shielding. can. be. used. to. interrupt. the.
path.between.the.source.and.the.worker..Polished.surfaces.make.the.best.barriers,.
although.special.glass.or.metal.mesh.surfaces.can.be.used.if.visibility.is.a.problem..
Shields.should.be.located.so.that.they.do.not.interfere.with.air.low,.unless.they.are.
also. being. used. to. reduce. convective. heating.. The. relective. surface. of. the. shield.
should.be.kept.clean.to.maintain.its.effectiveness.
Administrative. controls,. such. as. training,. are. the. key. to. good. work. practices..
Unless. all. employees. understand. the. reasons. for. using. new. or. changing. old. work.
practices,. the. chances. of. such. a. program. succeeding. are. greatly. reduced.. NIOSH.
(1986). states. that. a. good. heat. stress. training. program. should. include. at. least. the.
following.components:
.
1.. Knowledge.of.the.hazards.of.heat.stress
.
2.. Recognition.of.predisposing.factors,.danger.signs,.and.symptoms
.
3.. Awareness. of. irst. aid. procedures. for,. and. the. potential. health. effects. of,.
heat stroke
.
4.. Employee's.responsibilities.in.avoiding.heat.stress
.
5.. Dangers.of.using.drugs,.including.therapeutic.ones,.and.alcohol.in.hot.work.
environments
.
6.. Use.of.protective.clothing.and.equipment
.
7.. Purpose.and.coverage.of.environmental.and.medical.surveillance.programs.
and.the.advantages.of.worker.participation.in.such.programs
Hot. jobs. should. be. scheduled. for. the. cooler. part. of. the. day,. and. routine. main-
tenance. and. repair. work. in. hot. areas. should. be. scheduled. for. the. cooler. seasons.
of. the. year.. Other. administrative. controls. are. to. reduce. the. physical. demands. of.
work.. For. example,. reduce. the. amount. of. excessive. lifting. or. digging. with. heavy.
objects;.provide.recovery.areas,.such.as.air-conditioned.enclosures.and.rooms;.use.
shifts,.such.as.early.morning,.cool.part.of.the.day,.or.night.work;.use.intermittent.
rest.periods.with.water.breaks;.use.relief.workers;.use.worker.pacing;.assign.extra.
