Environmental Engineering Reference
In-Depth Information
stair. rail. system. and. the. stairway. steps.. Screens. or. mesh,. when. used,. must. extend.
from.the.top.rail.to.the.stairway.step.and.along.the.opening.between.top.rail.supports.
Intermediate.vertical.members,.such.as.balusters,.when.used,.must.not.be.more.
than. 19. inches. apart.. Other. intermediate. structural. members,. when. used,. must. be.
installed.so.that.there.are.no.openings.of.more.than.19.inches.wide.
Handrails. and. the. top. rails. of. the. stair. rail. systems. must. be. able. to. withstand,.
without.failure,.at.least.200.pounds.of.weight.applied.within.two.inches.of.the.top.
edge. in. any. downward. or. outward.direction,. at. any. point. along. the. top. edge.. The.
height.of.handrails.must.not.be.more.than.37.inches.nor.less.than.30.inches.from.the.
upper.surface.of.the.handrail.to.the.surface.of.the.tread..The.height.of.the.top.edge.
of.a.stair.rail.system.used.as.a.handrail.must.not.be.more.than.37.inches.nor.less.than.
36.inches.from.the.upper.surface.of.the.stair.rail.system.to.the.surface.of.the.tread.
Stair.rail.systems.and.handrails.must.be.surfaced.to.prevent.injuries.such.as.punc-
tures.or.lacerations.and.to.keep.clothing.from.snagging..Handrails.must.provide.an.
adequate. handhold. for. employees. to. grasp. to. prevent. falls.. The. ends. of. stair. rail.
systems.and.handrails.must.be.built.to.prevent.dangerous.projections,.such.as.rails.
protruding. beyond. the. end. posts. of. the. system.. Temporary. handrails. must. have. a.
minimum.clearance.of.3.inches.between.the.handrail.and.walls,.stair.rail.systems,.
and. other. objects.. Unprotected. sides. and. edges. of. stairway. landings. must. be. pro-
vided.with.standard.42-inch.guardrail.systems.
sAWs, PortABle cIrculAr (29 cFr 1910.243)
All.portable,.power-driven.circular.saws.(except.those.used.for.cutting.meat)..having.
a. blade. diameter. greater. than. 2. inches. must. be. equipped. with. guards. above. and.
below.the.baseplate.or.shoe..The.upper.guards.shall.cover.the.saw.to.the.depth.of.the.
teeth,.except.for.the.minimum.arc.required.to.permit.the.baseplate.to.be.tilted.for.
bevel.cuts..The.lower.guard.is.to.cover.the.saw.to.the.depth.of.the.teeth,.except.for.
the.minimum.required.to.allow.proper.retraction.and.contact.with.the.work..When.
the.tool.is.withdrawn.from.the.work,.the.lower.guard.is.then.automatically.returned.
to.the.covering.position.
scAFFolds (29 cFr 1910.28)
Analysis.of.1986.BLS.data.to.support.OSHA's.scaffolding.standard.estimates.that,.
of.the.500,000.injuries.and.illnesses.occurring.in.the.construction.industry..annually,.
10,000.are.related.to.scaffolds..In.addition,.of.the.estimated.900.occupational.fatali-
ties.occurring.annually,.at.least.80.are.associated.with.work.on.scaffolds..Seventy-two.
percent.of.the.workers.injured.in.scaffold.accidents,.covered.by.the.BLS.study,.were.
attributed.to.either.the.planking.or.support.giving.way,.or.to.the.employee.slipping.or.
being.struck.by.a.falling.object..Plank.slippage.was.the.most.commonly.cited.cause.
All. scaffolds. and. their. supports. must. be. capable. of. holding. the. load. they. are.
designed.to.carry.with.a.safety.factor.of.at.least.4..All.planking.must.be.of.scaffold.
grade,.as.recognized.by.grading.rules.for.the.species.of.wood.used..The.maximum.
permissible.spans.for.2-inch.by.9-inch.or.wider.planks.are.shown.in.the.following.
table.(see.Table 25.1).
