OSHA-Scaffolding Desig
Transcript of OSHA-Scaffolding Desig
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Occupational Health and Safety Code 2009Explanation Guide Part 23
Part 23 Scaffolds and Temporary WorkPlatforms
Highlights
Section326requiresemployerstovisuallyinspectandtagallsitebuiltscaffolds
before initialuseandat leastevery21calendardayswhile inuse.Scaffold tag
coloursaregreen forSafe forUse,yellow forCaution:PotentialorUnusual
Hazard,andredforUnsafeforUse.
Section347listsnumerousstandardsapplicabletoelevatingplatformsandaerial
devices.ElevatingplatformsandaerialdevicesmustcomplywiththeCanadian
StandardsAssociation (CSA)orAmericanNationalStandards Institute (ANSI)
standards
referenced
in
this
section.
Section349presentsrequirementsforforkmountedworkplatformsintendedto
support a worker. The section also prohibits workers from being on these
platformwhile the poweredmobile equipment the platform is attached to is
movingalongtheground.
Section351requiresaprofessionalengineertocertifyaboatswainschairifitis
notcommerciallymanufactured.
Requirements
Section 323 CSA Standard applies
CSA Standard CAN/CSAS269.2M87 (R2003), Access Scaffolding for Construction
Purposes, provides rules and requirements for the design, fabrication, erection,
inspection, testing,maintenance and use of scaffolding equipment,materials and
equipmentwhere scaffolds are erected to provideworking platforms forworkers
andmaterialsduring theconstruction,alteration, repairordemolitionofbuildings
andother
structures.
The
Standard
does
not
apply
to
(a) suspendedscaffoldsorswingstages,
(b) truckorvehiclemountedplatforms,
(c) falsework,
(d)shoring,or
(e) selfelevatingworkplatforms.
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The following isa selectionof requirementswithin theStandard.Usersof theOHS
CodemustcomplywiththeserequirementsandallothersintheStandard.
UsedLumber
Where lumber hasbeenmechanicallydamaged (including repeated nailing of
the same piece of lumber to the point that its mechanical integrity is
questionable)orhasdeteriorateddue to insects,decay,or chemicalattack, the
lumbermustnotbeusedunlessaqualified lumbergrader regrades it. (Clause
4.3)
LoadsonGuardrails,MidrailsandStairHandrails
Railsmustbecapableofresisting,withoutfailure,asinglepointloadofnotless
than 900 newtons (202 poundsforce) applied in any direction on any span.
(Clause5.5.1)
Postsmustbecapableofsupporting,withoutfailure,asinglepoint loadofnot
lessthan900newtons(202poundsforce)appliedinanydirectionatthelevelof
thetoprail.(Clause5.5.2)
GeneralStabilityofScaffolding
Theratioofmaximumheighttominimumhorizontalwidthofanaccessscaffold
must not exceed 3:1, unless lateral support is provided as required below.
(Clause6.6.2)
ExternalLateralSupports
External lateralsupportsmustbe installedatvertical intervals,notexceeding3
timestheminimumwidthofthestructure,andateverythirdbayofscaffolding
longitudinally.(Clause6.6.3)
Externallateralsupportsmustconsistof
(a) arigidconnectiontoanotherstructureorbuilding,or
(b)guy
wires
or
other
supplementary
devices
securely
fastened
to
adequate
anchors.
External lateral supportsmustbe installed at vertical intervals not exceeding
every third tierandevery thirdbayofscaffolding longitudinally,or6.4metres
(21feet),whicheverisless.(Clause6.6.3.1)
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Sills
A sill is awood, concrete ormetal footingused todistribute the load from a
standardorverticalpostorbaseplatetotheground.Sillsmustbesound,rigid
andcapableofadequatelysupportingthemaximumloadtowhichthescaffoldis
likelytobesubjected.Anysettlingordeformationofthesillshouldnotaffectthe
stabilityofthescaffold.(Clause6.6.8.2)
To ensure proper distribution, sills must be continuous at least under two
consecutiveverticallegsorverticalsupportingmembersasshowninFigure23.1.
(Clause 6.6.8.3).ThisCSA requirement is considered to apply to scaffolds that
userigidscaffold frames.AlthoughFigure23.1showssillsmadeofwood,sills
can alsobemade ofmaterials such as concrete e.g.baseplatesmay rest on a
concrete slab that serves as a sill, and metal. Regardless of their material of
construction, sillsmustbe sound, rigid, and capableof adequately supporting
theload
to
which
the
scaffold
is
likely
to
be
subjected.
Continuoussillsmaynotbepractical,safe,orappropriateinsituationswherethe
terrain isuneven and cannotbe leveled.A tube and clamp or similar type of
scaffold that allows the use of variable lengths legs may be required to
compensateforelevationvariationsinthesurfaceonwhichthescaffoldrests.In
suchcasestheuseofacontinuoussillislikelyimpossible.
Figure 23.1 Mudsill layout
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Areas Requiring Special Attention in Foundation Design
Specialconsiderationneedstobegiventothefollowingconditions:
(a) Inthe
absence
of
soil
tests
and
adetailed
design,
topsoil
or
other
unsuitable
materialmustbeexcavatedtoobtainanadequatebearingcapacityofnotless
than75kilonewtonspersquaremetre(1566pounds/squarefoot).Topsoilor
otherunsuitablematerialmustbeexcavatedifnecessarytoobtainadequate
bearingcapacity.
(b)When frozen ground is used as a foundation for all or part of the sills,
thawingmustbeprevented.
(c) Sills inareaswherevariabledegreesof foundationcompactionandbearing
capacityexists,as inpreviouslyexcavatedground, trenches,andbackfilled
areas,mustbedesigned to span soft areas, or other appropriatemeasures
mustbe
taken
to
limit
differential
settlement
to
acceptable
levels.
(d)Sillsinareassubjecttoerosion,suchastheedgesofslopesandterraces,must
beprotected.
(e) Reductionofbearing capacityof the foundationdue to changes inground
water elevationduring construction ordue to groundwater flowsmustbe
prevented.
(f) Sillsrestingonthinconcreteslabs,panorwaffleslabs,andslabscontaining
voids must be designed and located so as to safely distribute the
concentratedloads.
(g)Wheretherequiredfoundationbearingcapacitycannotbesafelydeveloped
by
other
means,
access
scaffolding
must
be
supported
on
piles
providing
the
requiredloadcapacity.(Clause6.6.8.6)
Leg Adjustments
Adjustmentdevicesmustbeprovidedatthebaseofalluprightsofframeswhere
foundationsettlement isuncertainor thesupportsurface isuneven,slopingor
stepped. Travel of adjustment devices must be mechanically limited to the
maximumtravelspecifiedinthemanufacturersspecifications.Ifextensionofthe
device reduces allowable load, such informationmust alsobe specified in the
manufacturersspecificationsandestablishedbytest.(Clause6.7.7)
Supervision and Erection Procedures
Only competent persons experienced in the erection of access scaffolding are
allowed to superviseassemblyof thescaffold.Thisensures that theerection is
carriedoutaccordingtoacceptablepractices,suchthat
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(a) therequirementsofthedrawingsorsuppliersliteraturearestrictlycomplied
with,
(b)no unusual settlement of foundations or strains in other external supports
occur,and
(c) thecorrectcomponentsandmaterialsarebeingused.
(Clause7.2.1.1)
Sills and Foundations
When foundations for access scaffolding are located in areas where the soil
bearing capacity is, or is likely to become, inadequate to support the loads
withoutdetrimentalsettlement,
(a) thesoilbeneathsillsmustbestabilizedwithcementtoanadequatedepth,
(b) soilbeneathsillsmustberemovedandreplacedwithconcretehavingalow
cementcontent,
(c) sillsmust
be
founded
on
alayer
of
compacted
gravel
150
to
300
millimetres
thick,or
(d)pilesmustbedrivenintothesoilbeneaththescaffoldingsupportstoprovide
adequateloadcarryingcapacity.
(Clause7.2.4.2)
Section 324 Design
Subsections 324(1)(a) and 324(1)(b)
Tieins anchor a scaffold to the structure it serves, preventing the scaffold from
falling into or away from the structure. Tieins also improve a scaffolds lateral
stabilitybybracingthestructure.Figure23.2showsseveralofthemanytypesoftie
ins that canbe used. A reveal tie is considered tobe a nonpositive tiein as it
dependson friction for itsholdingpower.Abox tie isapositive tieinbecause it
encircles an immovable portion of the structure.Anchorbolt ties are yet another
alternative.
Aparticular scaffoldor loadmay requireadditional tieins.The4.6metrevertical
and 6.4 metre horizontal intervals stated in the subsection are the minimum
distancesatwhichtieinsmustbeplaced.Tieinsmustneverbeplacedat intervals
greaterthantheseminimumdistances.
Insomesituations theremaybeanadvantage tousing tieins incombinationwith
outriggers(theuseofoutriggerswithfreestandingscaffoldsisdiscussedinsection
334). When used in combination, outriggers can stabilize the scaffold up to a
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maximumheight equal to 3 times the scaffolds smallestbasedimension.Beyond
thatheight,tieinsmustbeusedasdescribedinthissection.
Subsection 324(1)(c)
Hoardingrefers
to
tarps
or
other
materials
used
to
cover
ascaffold.
When
hoarding
isused,thestressonthetiesstabilizingthescaffoldincreasesduetowindloading.
Asaresult,thenumberoftieinsusedmustalsoincrease.Ratherthanthe4.6metre
vertical and 6.4 metre horizontal intervals required for scaffolds that are not
hoarded,hoardedscaffoldsrequiretieinsat3metreverticaland3metrehorizontal
intervals.Tieinsonhoardedscaffoldsmustneverbeplacedatintervalsgreaterthan
theseminimumdistances.
Subsection 324(1)(d)
Asrequired
by
Clause
7.2.3.1
of
CSA
Standard
S269.2
M87
(R1998),
Access
Scaffolding
for Construction Purposes, vertical loadcarrying members must be erected and
maintainedwithinthefollowinglimits:
(a) notmorethan12millimetres(0.47inches)outofplumbin 3metres (9.8
feet);
(b)notmorethan19millimetres(0.75inches)outofplumbin6metres (20feet);
or
(c) notmorethan38millimetres(1.5inches)intheheightofthestructure.
Departuresfromplumbmustbecorrectedbyadjustingthedevicesprovidedforthis
purpose,
e.g.
wedges,
jackscrews,
etc.
Devicessuchasbaseplatesandjackscrewseffectivelydisperse loads fromscaffold
verticalmemberstothescaffoldfoundation.Averticalmembercannotrestdirectly
onamudsill,boardorblockofwoodwithoutaninterveningloaddispersingdevice.
Thecompressiveforcescreatedattheendoftheverticalmembercaneasilyexceed
thestrengthofthesill,boardorblock,damagingitandmakingthescaffoldunstable.
Baseplates and mudsills
Ascaffoldtransmitsitsloadthroughitslegstoitsbaseplatesandmudsills,andthem
ontothe
foundation.
By
using
baseplates
and
mudsills
to
control
load
distribution,
workerserectingthescaffoldcansignificantlydecreasethelikelihoodoffoundation
failure.
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Figure 23.2 Examples of typical tie-ins
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The importance ofbaseplates andmudsills is evenmoredramatic if the leg load
transmitted to a foundationwithout them is considered. For example, consider a
light duty scaffold one tier high supporting 122 kilograms/square metre (25
pounds/square foot).Assume a total surface area of 3.7 squaremetres (40 square
feet)between its standards. This scaffold has a maximum intended load of 454
kilograms(1000pounds)liveload.Includeanestimated 227kilograms(500pounds)
for the scaffold dead load. The total leg load is therefore 681 kilograms (1500
pounds). Using the safety ratio of 4 times the intended load means that the
foundationmustsupport2722kilograms(6000pounds).
If the load is level, the 2722 kilograms (6000 pounds) load is distributed evenly
throughthelegstothefoundation.Eachlegreceives681kilograms(1500pounds)of
theload.Thisloadisconcentratedontheextremelysmallsurfaceareaofthescaffold
legasshowninFigure23.3.
Figure 23.3 Loading and cross-sectional area of the leg at the scaffold baseplate
Onascaffoldlegareaof25squaremillimetres(1squareinch),thecompressiveforce
fora681kilogram(1500pound)loadis 1,054,656.5kilograms/squaremetre(216000
pounds/square foot).This concentratedweightwilldrive the leg into any typeofsoil,punch it through asphalt surfaces, and even shatterwood, concrete, or stone
foundations.
Asweightistransferredfromthesmallsurfaceareasofthelegstothelargersurface
areas of baseplates or mudsills, the load per square unit of area decreases
significantly(seeFigure23.4).Forexample,a4536kilogram(10000pound)loadona
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0.09 squaremetre (1 square foot)baseplate transmits48,827kilogramsper square
metres (10000poundspersquarefoot)tothefoundation.A0.09metrex1.2metre(1
footx4 foot)mudsillunder thebaseplate reduces the load even further to 26,911
kilograms/squaremetre(2500pounds/squarefoot).Manysoilscansupportaloadof
thatweight.
Figure 23.4 Use of baseplate and sills reduces foundation loading
Baseplates
Baseplates help distribute concentrated leg loads over a larger area. They also
connectscaffold
standards
and
mudsills.
Baseplates
attach
to
scaffold
legs
with
pins
or locking devices. Workers erecting scaffolds often put screwjacksbetween the
scaffold legs andbaseplates to allow the scaffold tobe leveled (see Figure 23.5).
Baseplatesusuallycontainpredrillednailholesforattachingtheplatestoamudsill.
Abaseplatemeasuring150millimetresby150millimetresprovidesapproximately
0.023 square metres (36 square inches) of load distribution area. The load
distributionareaofa typicalscaffold leg isapproximately25squaremillimetres (1
squareinch).Thereforethebaseplatereducesleg loadforceonthefoundationbya
factorof36bydistributing the loadoveramuch largerarea.A0.04 squaremetre
(64squareinch)baseplatereducestheforceonthefoundationbyafactorof64.
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Figure 23.5 Baseplates help distribute the leg load
Mudsills
Normally, baseplates alone are inadequate for load distribution. Good erection
practice often includes a timbermudsill under thebaseplate.Mudsills serve two
purposes:
(1) Theyprovideafrictionsurfacebaseplatesaresmoothmetalandcaneasilyslip.A
timbermudsillhasmoretexture.Itdoesnotallowthebaseplatetoslipaseasily.
Mudsills alsohavemore surface area thanbaseplateswhichmeans theyhave
morecontact
with
the
surface
they
rest
on.
(2) Theydistribute loadsovera largerfoundationarea becausemudsillshavemore
surfaceareathanbaseplates,mudsillsdistributeanyloadplacedonthemovera
largerareaofthefoundation.
Mudsills are usuallymade ofwood and come inmany sizes.Workers erecting a
scaffold should choose a size according to the load and the foundation strength
required.For typicalscaffoldworkundernormalconditions,a50millimetrex250
millimetre(2
inch
x10
inch)
wood
mudsill
is
adequate.
Table
23.1
suggests
the
type
ofmudsillsthatshouldbeusedundervariousgroundconditions.
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Table 23.1 Sample mudsills
Subsection 324(2)
Ropesorwire ropesused in scaffoldingmaybe exposed topotentiallydamaging
processessuchasweldingoperationsorthecleaningofmasonrysurfaceswithacid
solutions. Where this is the case, the ropes must be made of heat or chemical
resistantmaterials.
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Subsection 324(3)
Unpainted,dressedlumberisspecifiedsothatitcanbeinspectedvisuallyfordefects
suchascracks,largeknotsorfaults.
Subsection 324(4)
This subsection presents tiein requirements specific to hoarded masonry walk
throughscaffoldframes.Thesescaffoldframesareapproximately2.1metresby2.1
metresinsize.Foranerectedmasonryscaffoldframetomaintainitsrigidity,tieins
shouldbe connected toboth sidesof a frameas close aspracticable tohorizontal
framemembers.Restricting the tiein points to the 3metre spacings requiredby
subsection324(1)(c)placesthetieinsatlessthandesirablelocationsthatcanreduce
the rigidity of the erected masonry scaffold and can restrict the movement of
workersand
materials
on
the
scaffold.
Subsection324(4)requiresaverticalandhorizontaltieinforeach9squaremetresof
hoarding surface area (3 metre horizontal x 3 metre vertical interval = 9 square
metres), regardless of the type of scaffold frame being used. This subsection
maintains the9 squaremetre surfacearea requirementwhileallowing thevertical
tieinspacingdistancetovarywithintherangeof2metresto3metrestobettersuit
thedimensionsofamasonrywalkthroughscaffold.
Subsection324(4)requiresthattheproductoftheverticaltieinspacingdistanceand
the
horizontal
tie
in
spacing
distance
equal
9
square
metres.
For
example,
(a)withaverticaltieinspacingof2metres,thehorizontaltieinspacingmustbeno
morethan4.5metres(2x4.5=9),
(b)withaverticaltieinspacingof2.5metres,thehorizontaltieinspacingmustbe
nomorethan3.6metres(2.5x3.6=9),or
(c) withaverticalspacingof3metres,thehorizontaltieinspacingmustbenomore
than3metres(3x3=9).
Horizontal tieinswillmost likelybe placed at every second frame [a horizontal
distanceof4.2metres(2x2.1metres)],resultinginverticaltieinsbeingspacedat2.1
metresintervals.
Subsection 324(5)
Aspoweredmobile equipment andvehiclesmoveaboutonawork site, they can
unintentionally contact unprotected scaffolding and temporary work platforms,
damaging these structuresandpossibly injuringworkers.This subsection requires
thatemployers takereasonablemeasures toprotectscaffoldingor temporarywork
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platformsfrombeingcontacted.Thismightbeachievedthroughselectiveplacement
ofthestructurestoeliminatethepotentialforcontact,orerectingorplacingbarriers
thatdirectequipmentandvehiclesawayfromthestructures.
Section 325 Load
Subsection 325(1) and 325(2)
Thissubsectionrequiresascaffoldtobecapableofsafelysupportingfourtimesthe
loadthatmaybe imposedonita4:1safetyfactor.Theimposedorintended load
consistsoftwocomponents:theliveloadandthedeadload.
The live load isthemaximumcombinedweightofallworkers,toolsandmaterials
placedon
the
scaffold
platform
at
any
given
time.
When
estimating
the
live
load,
assumeaweightof91kilograms(200pounds)foreachworkerand22.7kilograms
(50pounds)fortheworkerstoolsandaccessories,resultinginacombinedweightof
113.7kilograms (250pounds)perworkeron the scaffold.Multiply thenumberof
workersontheplatformbythisvalue,addingtotheresulttheestimatedweightof
anymaterialplacedonthescaffold.
Thedeadloadistheweightofthescaffolditselfandincludestheweightofallbases,
frames,posts, tubes,clamps,guardrails, toeboards, laddersor stairs,platformsor
planks, and any accessories. The dead load is estimatedbymultiplying the total
numberof
scaffold
parts
by
the
weight
of
each
part
and
taking
the
sum
of
the
resultingvalues.
Subsections 325(3) and 325(4)
Situationsmay arise inwhich a scaffoldmust support an evenlydistributed load
exceeding367kilograms/squaremetreor isofa typenotdescribed in thisPart.To
ensureworker safetywhen this is the case, the employer is required to have the
scaffold designed and certified by a professional engineer and constructed,
maintainedandusedinaccordancewiththeengineerscertifiedspecifications.
Subsection 325(5)
Workersmustbe aware of themaximum load the scaffold fromwhich they are
working is permitted to carry.Doing so ensures thatworkers use the scaffold as
intendedanddonotexceeditsloadlimit.Themethodbywhichworkersaremade
awareofthisinformationrestswiththeemployerandmayinvolvesignage,verbal
instructionsorapostednotice.
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Section 326 Tagging requirements
Subsections 326(1) through 326(5)
ThetaggingofscaffoldsfollowingvisualinspectionisarequirementnewtoAlberta.
Therequirementappliestothefollowingtypesofscaffolds:
(a)bracketscaffold;
(b)doublepolescaffold;
(c) needlebeamscaffold;
(d)outriggerscaffold;
(e) singlepolescaffold;
(f) suspendedscaffold;
(g) swingstagescaffold;and
(h)anysimilarsiteassembledscaffold.
Themeaningandcolourcodingofscaffold tags issummarized inTable23.2.Tags
neednotbe solidly coloured coloured stripes andbroken lines are acceptable.
Whenaperson looksat the tag, itscolourcodingmustclearlybegreen,yellowor
red.
Table 23.2 Summary of scaffold inspection tag requirements
Colour of inspection tag Wording to appear on tag
Green Safe for Useor similar wording
Yellow Caution: Potential or Unusual Hazardor similar wording
Red Unsafe for Useor similar wording
Thetagsletworkersknowthataparticularscaffoldissafeforuse,thatapotentialor
unusual hazard is present, or the scaffold is unsafe for use. The yellow tag is
requiredto
describe
any
precautions
to
be
taken
while
working
on
the
scaffold.
A
scaffoldbeingmodifiedon aparticular level requires ayellow tag.The tag alerts
workers climbing onto the scaffold of the modification work and any special
precautionsthatmightaffectthem.
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Tagsmustbeplacedateachpointofentrytothescaffold.Thisincludesaccesspoints
fromgroundlevelandanyaccesspointsfromthestructurewithwhichthescaffold
isbeingused.Doingsoensuresthatworkersareawareofthestatusandconditionof
the scaffold, regardless ofwhere they access it.Whatever their colour, tagsmust
include:
(a) thedutyratingofthescaffold,
(b) thedateonwhichthescaffoldwaslastinspected,
(c) thenameofthecompetentworkerwhoinspectedthescaffold,
(d)anyprecautionstobetakenwhileworkingonthescaffold,and
(e) theexpirydateofthetag.
Scaffoldstowhichthissectionappliesmustbe inspectedpriorto initialuseandat
least every 21 calendar days thereafterwhileworkerswork from the scaffold or
materials are storedon it.A scaffold that is erectedbutnot immediatelyput into
service,ornotusedformorethan21consecutivecalendardays,mustbetaggedwith
ared
tag
until
inspected
by
acompetent
worker.
A
scaffold
sitting
idle
may
be
exposed to weather or other circumstances that could make it unsafe for use.
Inspection,justpriortothescaffoldbeingputintoservice,confirmsthatitissafefor
workerstouse.
Subsections 326(6) and 326(7)
No worker can use a scaffold under the listed conditions unless the worker is
involvedintheerection,inspectionordismantlingofascaffold,andiscompetentto
do so.Workersperforming thesedutiesarespecially trained toperform thiswork
safely.
Section 327 Vertical ladder on scaffold
Subsections 327(1) and 327(2)
Workersmustsafelymoveupanddownladdersbymaintainingthreepointcontact
with the ladder at all times, and keeping their centre of gravity over the ladder
rungs. Ladders are intended for workers to move up or down the scaffold
workersmust not performwork from a ladder.These requirements apply to the
frameofascaffoldthatisdesignedtolooklikealadderandisusedasaladderby
workers.
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Subsection 327(3)
A ladder attached to a scaffold and that provides access to aworking level of a
scaffoldmustmeetthelistedconditions.Laddersmustextendatleast1metreabove
the uppermostworking level of the scaffold to provideworkerswith handholds
whengetting
on
to
or
off
of
the
ladder.
Themaximumunbrokenlengthoftheladderisrestrictedto9.1metresunlessafall
protection system complyingwith Part 9 is used (see subsection 327(5)). The 9.1
metresdistancewaschosentomakethismaximumunbrokenlengthconsistentwith
themaximumunbroken length for fixed laddersdescribed in section 130.The9.1
metredistanceismeasuredfromthegroundorbetweenworkinglevels.
If the ladderattached to the scaffold ismore than6.1metres inheight, itmustbe
equippedwithaladdercage.ForthepurposeoftheOHSCode,aladdercageisnot
consideredto
be
atype
of
fall
protection.
A
ladder
cage
provides
astructure
against
whichworkerscan leanandrest,and forsomeworkers it reduces theiranxietyor
senseofexposurebyenclosingthem.Shouldaworkerinaladdercagelosehisor
her footingandhandgrip, theworkerwillmost likelyplummet to thebaseof the
ladder unless their body becomes entangled in a ladder hoop. A properly
functioningfallprotectionsystemwillcatchtheworkerinmidairwithintheladder
cage,preventing themfromfallingtothebaseofthe ladder.The laddercagemust
beginwithin 2.4metresofthegroundorworkinglevelfromwhichtheunbroken
lengthofladderbegins.
Subsection 327(4)
This subsection recognizes two ladder cage shapes and places limits on their
dimensions.Circular laddercagesmusthavean insidediameter thatmeasuresno
more than760millimetres.Square ladder cagesmusthave insidedimensions that
measure nomore than 760millimetresby 760millimetres. These dimensions are
largeenoughtoallowworkerstoeasilymoveupanddownwithinthecage.Yetthe
dimensionsaresmallenoughtoensurethatworkerscancomfortablyleanbackinto
thecagewiththeirfeetpositionedontherungsandrestwithoutlosingtheirbalance.
Section 327(5)
Asdescribed in subsection327(3), themaximumunbroken lengthof the ladder is
restrictedto9.1metresunlessafallprotectionsystemcomplyingwithPart9isused.
The 9.1 metres distance was chosen to make this maximum unbroken length
consistentwiththemaximumunbrokenlengthforfixedladdersdescribedinsection
130.The9.1metredistanceismeasuredfromthegroundorbetweenworkinglevels.
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Ifa fallprotection systemcomplyingwithPart9 isused, themaximumunbroken
length of the ladder can exceed 9.1 metres and the ladder cage required by
subsection327(3)(f)isunnecessary.
Section 328 Working from a ladder
These requirementsapply to the frameofascaffold that isdesigned to look likea
ladder and is used as a ladderbyworkers. Such access ladders are intended for
workerstomoveupanddownthescaffold.Workersmustnotperformworkfrom
suchaladder.
Section 329 Scaffold planks
Subsection 329(1)
Manufacturedscaffoldplanksareoftenmadeofwoodlaminatesorcombinationsof
woodandmetal.Becausetheplanksmayhaveproperties thatdifferfrom thoseof
conventional solid sawn lumber, manufactured planks must be used, stored,
inspectedandmaintainedaccordingtothemanufacturersspecifications.
Readersarereferredtosection349ofthisExplanationGuideforadiscussionofthe
termcommerciallymanufactured.
Subsections 329(2) and 329(3)
Solid sawn lumber scaffold planks must be graded as scaffold grade or better.
Scaffoldgradeplanksareassessed againstnumerous criteria that includedensity,
knots,splits,warps,twists,decayanddimensions.Theseplanksarealsosubjectedto
deflectiontestsandarecapableofsupportingloadsexpectedduringscaffoldwork.
Planksthatmeetthe inspectioncriteriaarestampedasscaffoldgradeandbeara
gradestamp.
Subsection 329(4)(a)
Beforeinstallingascaffoldplankonascaffold,theplankmustbevisuallyinspected
toensureitissafeforuse.Normalwearandtearandstoragecandamageaplankto
the point that it is unsafe for continued use.Reasons for removing a plank from
service includedecay, conditions that reduce the thicknessorwidthof theplank,
damagedweldsinthecaseofmetalplanks,andcracksinmetalorcompositeplanks.
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Subsection 329(4)(b)
Ifvisual inspection revealsdamage thatcouldaffect the strengthof theplank, the
acceptabilityoftheplankforcontinuedusemustbeconfirmedbyloadtestingorthe
plankmustberemoved fromservice.Using thedeflectiontestproceduresand test
criteriaof
ANSI
Standard
A10.8
1988,
Construction
and
Demolition
Operations
ScaffoldingSafetyRequirements,thedeflectionofascaffoldplankunderitsdesign
loadmustnotexceedthespanlengthdividedby60.
Totestaplank,theplankisplacedonstablesupportssetattheplanksintendeduse
span.Theplank is thenweightedwith the intended loadat thecenterof thespan
andtheplanksdeflectionmeasured.
Ifaplank is intended to supportoneworkerovera2.4metre (8 feet) span,a113
kilogram (250pound) loadmustbeplacedat theplankscentreand the resulting
plankdeflection
measured.
The
deflection
must
not
exceed
1/60th
of
2.4
metres
a
distanceof40millimetres (1.6 inches). If theplank is to support twoworkers, the
ANSIStandardrecommendsplacingtwo113kilograms(250pounds)weightsonthe
plank,one460millimetres(18inches)totherightofcentreandone460millimetres
(18 inches) to the left of centre. If the plank is to support three workers, ANSI
recommendsplacingthree113kilograms(250pounds)weightsontheplank,oneat
the centre, one 460 millimetres (18 inches) to the left of centre and one 460
millimetres(18inches)totherightofcentre.
Subsection 329(4)(c)
Theminimum 150millimetre (6 inch) distance reduces the likelihood of a plank
slipping off its supporting ledger. Limiting the distance that a plank can extend
beyond its supporting ledger to 300 millimetres (12 inches) discouragesworkers
fromusing the extended area aspart of theirworkingplatform.This reduces the
chanceofaworkercausingtheplanktoflipupandoutofposition.
Subsection 329(4)(d)
Planksmaybe secured inmany differentways. Somewooden planks use cleats,
some steel or aluminum planks use hooks or recesses into which ledgers are
positioned.The
securement
method
must
prevent
movement
of
the
plank
in
any
directionthatmaycreateadangertoaworker.
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Subsection 329(4)(5)
Scaffoldplanksareoverlappedwhenscaffoldshavemultiplebaysandacontinuous
workplatformisrequired.Theoverlapinsuchcasesmustbeatleast300millimetres
(12inches)andoccuronlyoversupportsasshowninFigure23.6
Figure 23.6 Plank overlap
Section 330 Scaffold platform
Ascaffold
platform
is
araised,
typically
flat,
horizontal
floor
or
surface
that
supports
workers,materialandequipment.This sectionestablishes theminimumwidth for
theplatformofmost scaffoldsat500millimetres inorder toprovide an adequate
working space. Exceptions include ladderjacks, pumpjacks and similar systems
wherethewidthoftheplatformcanbenolessthan300millimetres.
This section also requires that therebe no space greater than 250millimetres in
widthbetweenanypartoftheplatformandastructureadjacenttotheplatform.This
istypicallythewallofabuildingorsimilarstructureandthisspaceisneededforthe
passage ofmaterials or equipment from one level to another.The 250millimetre
distance
is
measured
at
the
point
of
widest
separation.
Scaffold platforms should, ideally, be level in order to provide safe footing for
workers.Where, for the purposes of accomplishing thework, there is a need to
elevate one end of the platform, the surface of the platform must be such that
workersdonotsliporslide.
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Scaffolds areused for awide range ofpurposes and are often assembled around
pipesorcolumnsorotherstructures,resultinginanobstructionthatworkersmust
workaround.Insuchcases,theplatformmustbeconstructedtopreventthecreation
ofopeningsintoorthroughwhichaworkermightsteporfallthrough.
Section 331 Metal scaffolding
The requirements that apply to scaffold planks may not always apply to metal
scaffolding.Suchscaffoldingmustthereforebeerected,used,inspected,maintained
anddismantledaccordingtothemanufacturersspecifications.
Section 332 Bracket scaffolds
Bracketscaffoldshavetheirbracketshungoffofsupportingstructuressuchasthe
topofastructuresuchasavesselwall thescaffoldsupportsdonot reston the
ground.Planking then spans thebracketsanda safeworkingplatform is created.
The scaffold must meet the requirements of this section. Figure 23.7 shows an
exampleofatypicalbracketscaffold.
Figure 23.7 Typical bracket scaffold
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Section 333 Double-pole scaffolds
This type of scaffold is supported from the base by a double row of uprights,
independent
of
support
from
the
walls
and
constructed
of
uprights,
ledgers,
horizontal platform bearers and diagonal bracing. Figure 23.8 shows a typical
doublepolescaffold.Readersshouldcompare thisdesignofscaffold to thesingle
polescaffoldshownintheFigure23.15.
Figure 23.8 Typical double-pole scaffold
Section 334 Free-standing or rolling scaffolds
Subsection 334(1)
Figure 23.9 shows a typicalmanually propelled rolling scaffold. To optimize the
stabilityofthescaffold,itsmaximumheightisbasedonaheighttobasedimension
ratio of 3:1. The height of the scaffold is limited to three times the smallestbase
dimension. Properly installed outriggers permit the height of the scaffold to be
increasedbyincreasingthesmallestbasedimension.
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Figure 23.9 Typical manually propelled rolling scaffold
In some cases, rolling scaffolds are installed on a vehicle.When this is the case,
componentpartsofthescaffoldmayloosenovertimeduetovibration.Asaresult,
the scaffold shouldbe checked regularly tomake sure that all parts are securely
fastened together and the scaffold is securely attached to the vehicle. When
outriggers are used on such vehiclemounted scaffolds, the outriggers must be
securelyattachedtotheframeofthevehicle.
Topreventthescaffoldfromrollingwhileworkersworkfromthescaffold, locking
wheelsmustbelockedandnonlockingwheelsmustbeblocked.
Subsection 334(2)
Thissubsectionpermitsaworkertoremainonarollingscaffoldwhenitisinmotion
butattachesconditionstotheheightofthescaffoldandthesurfacesoverwhichthe
scaffold travels.Alevel surface isconsideredlevel if itvariesnomore than3
degreesfromhorizontal.Hazardsthatmaycauseascaffoldtotipincludepits,holes,
depressionsorobstructions.
Subsection 334(3)
Thissubsectionmakestheworkerresponsibleforlockingorblockingthewheelsofa
rollingscaffoldunderspecifiedconditions.
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Section 335 Half-horse scaffolds
Ahalfhorseorleantoscaffoldisasupportedscaffoldthatiskeptuprightbytilting
it
toward
and
resting
it
against
a
building
or
structure.
Lumber
sizes
for
half
horse
scaffoldsarespecifiedinTables5and6ofSchedule7oftheOHSCode.
Section 336 Ladderjack scaffolds
Figure 23.10 shows a typical ladderjack scaffold.The ladderjack scaffoldbrackets
mustbesupportedbythesiderailsoftheladdertowhichtheyareattachedorhave
at least90millimetres (3 inches)ofwidth restingon the ladder rung.Doing so
ensuresthattheweightofthescaffoldissafelytransferredontotheladders.
Figure 23.10 Typical ladderjack scaffold. Since the working platform is more than 3 metresabove the ground the workers are using personal fall arrest systems
Figure 23.11 shows a commerciallymanufactured aluminumplank that couldbe
usedonaladderjackscaffold.
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Figure 23.11 Commercially manufactured aluminum plank
Readersarereferredtosection349ofthisExplanationGuideforadiscussionofthe
termcommerciallymanufactuered.
Section 337 Needle-beam scaffolds
Figure23.12showsatypicalneedlebeamscaffold,highlightingseveralofthedesign
detailsthatmakethescaffoldsafeforuse.
Figure 23.12 Needle beam scaffold and design details
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Section 338 Outrigger scaffolds
Figure23.13 showsa typicaloutrigger scaffold.Anoutrigger scaffold isa scaffold
that
consists
of
a
platform
resting
on
outrigger
beams
or
thrustouts.
The
beams
projectbeyond the wall or face of thebuilding or structure, with inboard ends
securedinsidethebuildingorstructure.
Figure 23.13 Typical outrigger scaffold
Section 339 Roofing brackets
Figure23.14showsexamplesoftypicalroofingbrackets.
Figure 23.14 Examples of typical roofing brackets
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Section 340 Single-pole scaffolds
This section only applies towooden singlepole scaffolds (see Figure 23.15). This
type
of
scaffold
has
platforms
resting
on
putlogs
or
cross
beams,
the
outside
ends
of
which are supportedon ledgers secured to a single row ofposts oruprights, the
innerendsofwhicharesupportedonorinawall.Readersshouldcomparethisto
thedoublepolescaffoldshowninFigure23.8.
Figure 23.15 Example of a typical wooden single-pole scaffold intended for light duty service
Section 341 Suspended scaffolds
A suspended scaffold is a scaffold supported from abovebywires or ropes.This
type of scaffold is used for work on, or providing access to, vertical sides of
structuresonatemporarybasis.Figure23.16showsanexampleofaninteriorhung
suspendedscaffold.
Figure 23.16 Example of an interior hung suspended scaffold
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Theupperendofthesuspendedscaffoldssuspensionropemustbeterminatedina
splicedloopasshowninFigure23.17(a).Theclampedwireropearrangementshown
inFigure23.17(b)isunacceptablebecausetheconnectionmayloosenandslipifnot
properlymaintained.
Figure 23.17 Suspension rope terminations
Suspension ropesmustbeprevented from separating from the shackles towhich
theyareattached.AsecuringnutmustbeusedasshowninFigure23.18.
Figure 23.18 Suspension rope securement to thrustout shackle
Becausethesafetyandstabilityoftheworkingplatformreliesonthethrustoutsfrom
which it issuspended, thethrustoutsmustbesecurelyanchored tothebuildingor
structurefromwhichtheplatformissuspended.Counterweightscannotbeusedas
themethodofanchoringorstabilizingathrustout.Figure23.19showstwotypesof
properlysecuredthrustouts.
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Figure 23.19(a) Examples of thrustout correctly tied back to wall
Figure 23.19(b) Example of thrustout on rotating centre
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AsshowninFigure23.20,stopboltsmustbeinstalledattheouterendsofthrustouts
topreventshacklesfromslippingoffthethrustouts.
Figure 23.20 Stop bolts at end of thrustout
Readersarereferredtosection349ofthisExplanationGuideforadiscussionofthe
termcommerciallymanufactured.
Section 342 Swingstage scaffolds
Figure23.21 showsaswingstagescaffold inuse. Ifaswingstagescaffoldhasbeen
designed by a professional engineer rather than manufactured commercially,
operatingprocedurescertifiedbyaprofessionalengineermustbedeveloped.
Readersarereferredtosection349ofthisExplanationGuideforadiscussionofthe
termcommerciallymanufactured.
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Figure 23.21 Example of a swingstage scaffold
Section 343 Requirements for swingstage scaffold
Alightdutyscaffoldisintendedforworkersonly.Materialsotherthantoolsshould
notbe
stored
on
this
type
of
scaffold.
Such
ascaffold
is
designed
to
support
the
equivalentofanevenlydistributedloadofnomorethan122kilograms/squaremetre
(25pounds/squarefoot).
Figure 23.21 shows the proper parallel positioning of suspension ropes. This
positioning eliminates the creationof lateral forceson those structures supporting
theropes.Lateralforcescouldcausethrustoutsandthrustoutblockingtosuddenly
shift,damageparapets,andcausetheswingstagetobecomeunstable.Figure23.22
showssuspensionropesthathavebeenpositionedimproperly.
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Figure 23.22 Improper suspension rope positioning
A parapet or cornice hook is a device that functions as a portable or temporary
anchorforasuspensionline.Aparapetclampfunctionsasaportableortemporary
anchorforasuspensionline,lifelineortiebackline(Figure23.23showsbothdevices
inuse).Assuch,eachhookorclampshouldbedesignedwithaminimumbreaking
strength of 22.2 kilonewtons (5000 poundsforce). If a parapet clamp is used to
anchor a lifeline i.e. life safety rope (vertical lifeline), it must have a minimum
breakingstrengthof16kilonewtons(3600poundsforce)ortwotimesthemaximum
arrestingforce
per
worker
attached
as
required
by
subsection
152.1(2).
The tiebackofa thrustout,parapethookorparapetclampcanonly functionasan
effective anchor if it is positioned on a part of thebuilding or structure that is
structurallysoundandable tosupport the loads that the tiebackwillapply.These
tiebacksshould,asmuchaspossible,beriggedatrightangles to thebuilding face
fromwhichthescaffoldissuspended.Selectionofpropertiebackpointsisextremely
important.
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Figure 23.23 Parapet clamp and parapet or cornice hook
Aconstantpressurecontrolisonethatrequiresadeliberate,sustainedapplication
of forceby ahumanbodypart for themachine tooperate.Removal of this force
immediatelystops themachine fromoperating.Acontrolequippedwitha locking
mechanism
that
keeps
the
control
active
without
contact
by
a
human
body
part
is
unacceptable.
Positive drive, in relation to a swingstage scaffold power unit,means that the
powerunitactivelydrives the stage inboth theupanddowndirections.Anon
positiveorfreewheelingpowerunitdrivesthestageupbutpermitsittodescend
freely.
Section 344 Safety on swingstage scaffolds
Failureofthehoistingmechanismofamanuallyoperatedswingstagescaffoldcould
cause the scaffold to drop uncontrollably. To prevent this, allmanually operated
swingstage scaffolds must be equipped with a secondary antifall device that
connects the scaffold to the suspension rope at a point above the hoisting
mechanism.
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In case of amechanical or power failure,workersmustbe able to safely leave a
powered swingstage scaffold. In the caseofabuildingwithwindowsdesigned to
open,oronbuildingsunderconstructionwithaccess tocompleted floors,workers
may be able to safely leave the stage without the need for any additional or
specializedequipment.
However, where workers cannot safely leave the stage as described above, the
scaffold must be equipped with a manually operated secondary mechanism
perhapsthepowerunitsarecapableofbeingconvertedtomanualoperationoran
escapedevice.Thepurposeofthesecondarymechanismistopermitthestagetobe
positionedsothatworkerscansafelyleaveit.Thepurposeoftheescapedeviceisto
permitworkerstoreachapointofsafeexit.Theescapedevicecannotbeavertical
lifelineusedbyaworkerforfallprotection.
Section 345 Workers on swingstage scaffolds
Subsections 345(1) to 345(3)
Ropesi.e.lifesafetyropes(verticallifelines)thatextendtothegroundoralanding
mustbesecuredtopreventthemfromgettingentangledinequipmentorvehicular
andpedestriantraffic.Figure23.24showsexamplesofhowthismightbedone.
Figure 23.24 Examples of how to secure ropes
Maintaining the stage levelwithin the specified 10percent limit helps toprevent
workersfromfalling,materialsfromupsetting,andriggingfrombeingsubjectedto
excessivewear.
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Workersmust remainbetween the swingstages stirrups for their personal safety
andtopreventthepossibilityofthestagebecomingunstable.Stirrupsarethemain
supportbracketslocatedateachendofthestageandontowhichthehoistingdevices
arenormallyattached.Theyarealsocommonlyknownassuspensionbrackets.
Workersmustnotbridgethedistancebetweentwoormorescaffoldswithplanksor
similar connectingmaterials.Thisprohibition is consistentwith subsection 344(7).
Figure23.25showswhatbridgingscaffoldsmeans.
Figure 23.25 Bridging between two or more scaffolds is not permitted
Subsections 345(4) and 345(5)
Workersworking froma suspended scaffoldmustbeprotected from falling.Two
cables suspend most swingstage scaffolds, one at either end of the scaffold.
However,other
swingstage
scaffolds
are
available
with
two
suspension
cables
at
eachend,aprimaryandasecondarysuspensioncable.
TheCanadianStandardsAssociation(CSA),inclause5.3.4ofCSAstandardZ9102,
HealthandSafetyCodeforSuspendedEquipmentOperationsandclause7.2.3.2ofCSA
standardZ27198,SafetyCodeforSuspendedElevatingPlatforms,recognizestheuseof
swingstagesinwhichthefailureofonesuspensionropewillnotsubstantiallyalter
thepositionofthesuspendedswingstage.Thistypeofswingstagehasprimaryand
secondarysuspensionlinesateachendoftheswingstage.
Withthis
type
of
swingstage,
CSA
states
that
aworkers
personal
fall
arrest
system
canbeattachedtoahorizontallifelineoranchorageontheswingstageitself,rather
thanthetraditionalapproachinwhichworkersareattachedtoaverticallifelinei.e.
life safety rope, secured to an anchorage integral to the structure fromwhich the
swingstageissuspended.
Subsection345(5)nowrecognizesthissituation.
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Section 346 Worker safety
Thissectionprohibitsaworkerfromremaininginoronamovingbasket,bucketor
other
elevating
platform
in
situations
where
doing
so
creates
a
danger
to
the
worker.
Examplesofsuchsituationsincluderoadtrafficconditionsinwhichthereisreduced
or restrictedvisibility, or road surfaces are too slippery for safe travel.Overhead
wiresandcablesmaybeanelectricalcontacthazardiftheyareenergized,orpresent
anentanglementhazard.
Wheretheworkerisnotinanydanger,theworkermayremaininoronamoving
basket,bucketorotherelevatingplatform.Thisofteninvolvesmovingashortdistance,
asmightoccurbetweenstreetlampsduringbulbreplacementorlampcleaning.In
spiteofthissubsection,theemployermustcomplywiththemanufacturers
specificationsformovementwithaworkeronboard.
Section 347 Standards
Subsection 347(1)
CSA Standard
CSA Standard B354.402 applies to all integral frame,boomsupported elevating
work platforms used to position personnel, alongwith their tools and necessary
materials,atoverheadworklocations.Theboommaytelescope,articulate,orrotate,
andextend
the
platform
beyond
the
base
dimensions.
The
platform
is
power
operatedwithprimaryfunctionscontrolledfromtheplatform.Theequipmentmay
bemanually or selfpropelled. Figure 23.26 shows examples of typicalboomtype
elevatingworkplatforms.
Figure 23.26 Articulated boom and aerial device
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Anarticulatedboom isaboommadeof twoormorehingedsections thatsupport
theworkplatform.Atelescopingboomisoneinwhichmotioncreatedbetweentwo
ormoreboomsections is ina longitudinaldirection that lengthensorshortens the
boom.
Clause 8.1 of the CSA Standard requires the platform to be equipped with a
guardrailorotherequivalentstructure.Chain,oritsequivalent,maybesubstituted
asthetoprailormidrailacrossanaccessopening.Clause8.3oftheStandardrequires
fallprotectionanchoragepoint(s)tobeinstalledontheworkplatform.
The Standarddoes not require theplatform tobemarked as complyingwith the
Standard.However,apermanentplatemustbelocatedontheplatformthatlists:
(a) themake,model,serialnumberandthemanufacturersnameandaddress;
(b) theratedworkingload;
(c) themaximumplatformheight;
(d)themaximum
horizontal
reach;
(e) specialwarnings,cautions,orrestrictionsnecessaryforsafeoperation,including
theuseofoutridersorstabilizers;and
(f) theoperatinginstructionsandanoticeindicatingtheneedtoreadtheoperating
manualbeforeuse.
The product manufacturer can provide confirmation of compliance with the
Standard.
ANSI Standard
ANSIStandardA92.52006,BoomSupportedElevatingWorkPlatforms,appliestoself
propelledintegralchassisaerialplatformshavingaplatformthatcanbepositioned
completelybeyondthebaseandusedtopositionworkers,alongwiththeirnecessary
toolsandmaterials,atworklocations.Aerialplatformsarepoweroperatedwith
primaryfunctions,includingdrive,controlledfromtheplatform.Suchaerialplatforms
areintendedtobeoccupiedwhendriven.Figure23.26showsexamplesoftypical
boomsupportedelevatingworkplatforms.
The Standard sets criteria for the design, manufacture, performance, inspection,
training,maintenance, testingandoperationof theplatforms.Clause 4.12.5of the
Standard requiresboomsupported elevatingworkplatforms tobe equippedwithanchorage(s) for personal fall protection for fall protection devices for workers
occupying theplatform.Clause4.12.2 requires suchplatforms tohave aguardrail
system. Flexible materials such as cables, chains or ropes cannotbe used in the
guardrailsystem.
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AboomsupportedelevatingworkplatformcomplyingwiththeANSIStandardwill
have a manufacturerinstalled nameplate indicating that the equipment complies
withtheStandard.
Subsection 347(3)
CSA Standard
CSAStandardCAN/CSAB354.2.01,SelfPropelledElevatingWorkPlatforms, applies
toselfpropelled integralchassiselevatedworkplatformsthathaveaplatformthat
cannotbe positioned completelybeyond thebase and that are used to position
personnel, alongwith theirnecessary tools andmaterials, atwork locations. Self
propelled elevating work platforms (aerial platforms) are power operated with
primary functions, including drive, controlled from the platform. The Standard
appliestoaerialplatformsdesignedforuseinbothonslabandoffslabapplications.
Anonslab surfacemeansanyasphalt,concrete,orequivalent surface.Anoffslab
surfaceisanunevensurfacemadeofmaterialsotherthanasphalt,concrete,ortheir
equivalent.Compacted soil is an example of an offslab surface.Work platforms
intendedforoffslabworkaremorestablethanthoseintendedforuseonpaved/slab
surfaces.
TheStandardspecifies theminimumrequirements for theestablishmentofcriteria
for the design, manufacture, remanufacture, rebuild/recondition, testing,
performance,inspection,training,maintenance,andsafeoperationofselfpropelled
elevating
work
platforms.
Selfpropelled elevatingwork platforms are generally intended for use over level
surfaces.Normallytheyarenotinsulatedforusenearelectricallyenergizedcircuits
nor are they intended tobe used in hazardous locations.The term selfpropelled
meansthatthemachinecanbepowerdrivenusingaprimarysetofoperatorcontrols
locatedontheelevatedworkplatform.Figure23.27showsexamplesoftypicalself
propelledelevatingworkplatforms.
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Figure 23.27 Examples of powered (self-propelled) elevating platforms
Clause4.13.2oftheStandardrequirestheplatformtobeequippedwithaguardrail.
Clause4.13.5requiresfallprotectionanchoragepoint(s)tobeinstalledonthework
platform. The platform must be equipped with one anchorage point for each
occupant.
The Standarddoesnot require the platform tobemarked as complyingwith the
Standard.However, theplatformmustbedurablymarkedwithvariouswarnings
andinstructions.Thefollowingisapartiallistofwhatisrequiredbyclause4.19.1of
theStandard:
(a) themake,model,serialnumberandthemanufacturersnameandaddress;
(b) theratedworkingload;
(c) themaximumplatformheight;
(d)specialwarnings,cautions,orrestrictionsnecessaryforsafeoperation,including
theuseofoutridersorstabilizers;and
(e) theoperatinginstructionsandanoticeindicatingtheneedtoreadtheoperating
manualbeforeuse.
The product manufacturer can provide confirmation of compliance with the
Standard.
ANSI Standard
ANSIStandardANSI/SIAA92.62006,SelfPropelledElevatingWorkPlatforms,applies
toselfpropelled integralchassisaerialplatformshavingaplatform thatcannotbe
positioned completelybeyond thebase and that are used to position personnel,
alongwith their toolsandmaterials,atwork locations.Aerialplatformsarepower
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operated with primary functions, including drive, controlled from the platform.
Figure23.27showsexamplesoftheequipmentcoveredbytheStandard.
The Standard sets criteria for the design, manufacture, remanufacture,
rebuild/recondition, testing, performance, inspection, training, maintenance and
operationoftheplatforms.
The ANSI Standard allows manufacturers to voluntarily include fall protection
anchorages on their equipment. When provided, Clause 4.13.5 of the Standard
requirestheanchorage(s)forpersonalfallprotectiontobecapableofwithstandinga
loadof16kilonewtons(3,600poundsforce).Specialrequirementsapplyifmorethan
oneworkerusesasingleanchorageatonetime.
Clause4.13.2 requiresallworkplatforms tobeequippedwithaguardrail system.
Flexiblematerialssuchascables,chainsandropescannotbeused in theguardrail
systemexcept
as
amidrail
at
access
openings
760
millimetres
(30
inches)
wide,
or
less.
A selfpropelled elevatingworkplatform complyingwith theANSIStandardwill
have amanufacturedinstalled nameplate indicating that the equipment complies
withtheStandard.
Subsection 347(4)
CSA Standard
CSA Standard CAN3B354.12004, Elevating Rolling Work Platforms, applies to
elevating rollingworkplatformsusedona level surfaceand thatare incapableof
being selfpropelled from an operating station on the work platform. The work
platforms are used to position workers, along with their tools and necessary
materials, at overhead work locations. The Standard describes requirements and
recommended practices for product design and manufacture, lists performance
criteria,andsetsstandardsfortestingandinspection.Figure23.28showsthetypeof
equipmenttowhichthisStandardapplies.
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Figure 23.28 Examples of manual elevating platforms
The Standarddoesnot require the platform tobemarked as complyingwith the
Standard.However,apermanentplatemustbelocatedontheplatformthatlists:
(a) themake,model,serialnumberandthemanufacturersnameandaddress;
(b) theratedworkingload;
(c) themaximumplatformheight;
(d)themaximumhorizontalreach;
(e) specialwarnings,cautions,orrestrictionsnecessaryforsafeoperation,including
theuseofoutridersorstabilizers;and
(f) theoperatinginstructionsandanoticeindicatingtheneedtoreadtheoperating
manualbeforeuse.
The product manufacturer can provide confirmation of compliance with the
Standard.
ANSI Standard
ANSIStandardANSI/SIAA92.32006,ManuallyPropelledElevatingAerialPlatforms,
applies tomanuallypropelled, integral chassis aerialplatformshaving aplatform
thatcannot
be
positioned
completely
beyond
the
base
and
that
are
used
to
position
workers, togetherwith their tools andmaterials, atwork locations. Platforms are
adjusted by manual or powered means and cannot be occupied when moved
horizontally. This Standard sets criteria for the design, manufacture, testing,
performance, inspection, training, maintenance and operation of the platforms.
Figure 23.28 shows typical examples of the equipment to which the Standard
applies.
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Clause4.12.5oftheStandardrequirestheaerialplatformtobeequippedwithafall
protection anchor point(s) if the platforms guardrail system, or parts of the
guardrail system, canbe removed.Clause4.12.2 requiresallworkplatforms tobe
equipped with a guardrail system. Flexible materials such as cables, chains and
ropescannotbeusedintheguardrailsystem.
AmanuallypropelledelevatingaerialplatformcomplyingwiththeANSIStandard
will have a manufacturerinstalled nameplate indicating that the equipment
complieswiththeStandard.
Subsection 347(5)
CSA Standard CAN/CSAC22500 (R2005), VehicleMounted Aerial Devices, sets
criteria for the design,manufacture, testing, inspection, installation,maintenance,
useand
operation
of
vehicle
mounted
aerial
devices.
These
devices
are
installed
on
a
chassis,areprimarilyusedtopositionworkersforworkpurposes,andareusedfor
operator training. The vehicle may be a truck, trailer or allterrain vehicle. The
design and manufacturing requirements of the Standard apply to those devices
manufactured after thedate of publication of the Standard. Figure 23.29 shows a
typicalaerialdevice.
Figure 23.29 Example of a typical aerial device
TheStandardrecognizesboth insulatedandnoninsulatedaerialdevices.Insulated
aerialdevices are classified into three categoriesbased on thedegree of electrical
protectiontheyprovideandthetypeofworkbeingperformed.
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Clause4.9.4of theStandardrequires theworkplatform tobeequippedwitha fall
arrestanchor(s)capableofwithstandinga loadof22.2kilonewtons (5000pounds
force).Clause4.5.4oftheprevious1988editionoftheStandardrequiredanchorsto
haveastrengthof18kilonewtons(4000poundsforce).Specialrequirementsapplyif
more thanoneworkerusesa singleanchoratone time.Clause8of theStandard,
Responsibilities ofOwners, describeswhat is required of equipment owners in
termsofequipmentinspectionsandtests.
Althoughanattachednameplatemayshowcomplianceinformation,anaerialdevice
isnot requiredby theStandard tobearamarking indicating compliancewith the
requirementsoftheStandard.Wherecomplianceisinquestion,themanufacturers
specificationsshouldbeconsulted.
Subsection 347(6)
ANSI
ANSIStandardANS/SIAA92.91993,MastClimbingWorkPlatforms,appliestomast
climbing platforms primarily used to positionworkers, including their tools and
materials,so thatworkcanbeperformed.Platformscanbeadjustedbymanualor
powered means. The Standard sets criteria for the design, manufacture,
performance,inspection,training,maintenance,testingandoperationofthesework
platforms. Figure 23.30 shows examples of typical platforms covered by the
Standard.
A mastclimbing work platform complying with this Standard will have a
manufacturerinstallednameplate indicating that theequipmentcomplieswith the
Standard.
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Figure 23.30 Examples of typical mast-climbing work platforms
Subsection 347(7)
ANSIStandardANSI/SIAA92.81993 (R1998),VehicleMountedBridge Inspectionand
MaintenanceDevices,appliestomobileunitsgenerallydesignedtobesupportedon
bridge surfaces of varying degrees of grade and superelevation and have the
capability ofprovidingpersonnel quick and easy access to theunderside of such
structures.TheStandarddescribesrequirementsforthedesign,manufacture,testing,
inspection,installation,
maintenance,
use,
training
and
operation
of
such
devices.
Figure 23.31 shows typical examples of vehiclemounted bridge inspection and
maintenance devices. The device manufacturer can provide confirmation of
compliancewiththeStandard.
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Figure 23.31 Typical examples of vehicle-mounted bridge inspection and maintenance devices
Subsection 347(8)
ASMEStandardB56.12000,SafetyStandardforLowLiftandHighLiftTrucks,defines
safetyrequirementsrelatingtotheelementsofdesign,operationandmaintenanceof
low
lift
and
high
lift
powered
industrial
trucks
controlled
by
a
riding
or
walking
operator,andintendedforuseoncompacted,improvedsurfaces.
AnorderpickerlifttruckcomplyingwiththeStandardwillhaveamanufacturer
installednameplateindicatingthatthelifttruckcomplieswiththosemandatory
requirementsoftheStandardapplicabletothemanufacturer.Thelifttruckmayalso
bearothermarkings,authorizedbyanappropriatenationallyrecognizedtesting
laboratory,indicatingcompliancewiththeStandard.
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Thissubsectionappliestobothhighliftandlowliftorderpickers.TheASMEStandard
definesthisequipmentasfollows:
highliftorderpickertruckmeansahighlifttruckcontrollablebytheoperator
stationedonaplatformmovablewiththeloadengagingmeansandintended
for(manual)stockselection.Thetruckmaybecapableofselfloadingand/or
tiering.Figure23.32showsanexampleofsuchatruck.
Figure 23.32 High lift order picker rider truck
lowliftorderpickertruckmeansalowlifttruckcontrollablebyanoperator
whenstationed
on,
or
walking
adjacent
to,
the
truck,
and
intended
for
(manual) stock selection. The truckmaybe capable of selfloading. Figure
23.33showsanexampleofsuchatruck.
Figure 23.33 Low lift order picker truck
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Section 348 Permanent suspension powered work platforms
Thissectionapplies toequipment that ispermanently installedona structureand
includesasuspendedworkingplatform,aroofcar,orothersuspensionmeans,track
orguidance
systems,
and
the
required
operating
and
control
devices.
This
is
in
contrast to portable powered platforms such as swingstages which are removed
from their points of suspension after each use and are normally handled on the
ground.
CSA Standard CAN/CSAZ27198 (R2004), Safety Code for Suspended Elevating
Platforms,appliestothedesign,construction,installation,operation,inspection,test,
maintenance, alteration, and repair of suspended elevating platforms designed to
carrypersonnel for thepurposeofgainingaccess toexteriorand interiorbuilding
surfaces and other structures. The Standard also applies to manually operated
platformsand
boatswains
chairs.
Section 349 Fork-mounted work platforms
Subsection 349(1)
This sectionapplies toacageorworkplatformmountedon the forksofpowered
mobileequipmentandintendedtoonlysupportmaterial.Thecageorworkplatform
mustbe
securely
attached
to
the
lifting
carriage
or
forks
of
the
powered
mobile
equipment. Doing so prevents the cage or platform from accidentally moving
laterallyorverticallyandpreventsthepoweredmobileequipmentfromtipping.
Subsection 349(2)
Because theworkplatform is intended tosupportaworker, itmustmeetahigher
standard of design and construction than is requiredby subsection 349(1) for a
platformintendedtoonlysupportmaterial.Thismeansthattheworkplatformmust
becommerciallymanufacturedordesignedandcertifiedbyaprofessionalengineer
ifnotcommerciallymanufactured.Thisisthesamestandardofsafetythatappliesto
suspended man baskets (see subsection 350(1)), a type of work platform thatsimilarlysupportsworkersataheightabovegroundlevel.
Theworkplatformmustbeequippedwithguardrailsandtoeboards.Guardrailsact
asatypeoffallprotectionandthetoeboardspreventsmallobjectsfromfallingoff
theplatform.
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The platformmustbe equippedwith a screen or similarbarrier that guards any
drivemechanismaccessibletoaworkerwhileontheworkplatform.Thisscreenor
barrier is intended toprotectaworkeron theplatform fromcontactwithmoving
partsassociatedwiththeliftingorloweringmechanism.
For more information
ASME Standard B56.12000, Safety Standardfor Low Lift and High Lift Trucks.Clause7.36presentsdesignspecificationsforelevatingworkplatforms
Thefallprotectionapproachtobefollowedwhenusingaforkmountedwork
platformdependsonthetypeofforkliftbeingused.Thetwosituationsnormally
encounteredaresummarizedasfollows
Forklift truck with vertical mast
Whenaworkplatformisattachedtoaforklifttruckhavingaverticalmastandthe
platformonlymovesupanddown, then theplatformsguardrailsystemprovides
worker protection against falls.However, if a portion of the guardrail system is
absentorhas toberemovedwhile inanelevatedpositionand itsabsenceexposes
the worker to an edge fromwhich the worker could fall, then additional safety
measuresmustbetaken.Specifically,theworkermustuseeitheratravelrestraintor
personalfallarrestsystem.Becauseofthe(usually)limitedclearancedistancebelow
theworkplatform,a travel restraint system consistingof a self retracting lanyard
andfullbodyharnessispreferred.
Forklift truck with telescopic mast
Inastudyofdeaths involvingaerialworkplatformsused in theU.S.construction
industry between 1992 and 1999, it was determined that boomsupported work
platformsaccountedforalmost70percentofdeathsinvolvingaerialworkplatforms.
Thestudyreportedthat
(a) half of all falls fromboomsupported work platforms involvedbeing ejected
fromthebucketorplatformafterbeingstruckbyvehicles,cranes,orcraneloads,
orbyfallingobjects,orwhentheworkplatformsuddenlyjerked,and
(b) twothirds
of
the
deaths
from
collapses/tipovers
of
boom
supported
work
platformsoccurredwhenthebucketcableorboombrokeorthebucketfell.
Almostonethirdofthedeathswereduetotipovers.
Experience in Alberta about ejections has resulted in subsection 141(1) explicitly
requiring that workers use a personal fall arrest system when working from a
telescopicforklift truckworkplatform.Theworkers lanyardmustbeconnected to
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anengineeredanchorpoint.Theworkerslanyardmust,ifreasonablypracticable,be
shortenoughtopreventtheworkerfrombeingejectedfromtheworkplatformyet
belongenoughtoallowtheworkertoperformhisorherwork.Readersarereferred
totheexplanationtosection141oftheOHSCodeforadditionalinformation.
Subsection 349(3)
A worker working from an elevated forkmounted work platform relies on the
equipment operator toposition theworker up anddown.The operatormustnot
leavethecontrolswhileaworkerisontheelevatedworkplatform.
Subsection 349(4)
Nooneispermittedtoremainonaforkmountedworkplatformwhilethepowered
mobile equipment to which it is attached is being driven. The platform is not
designedto
protect
aworker
from
injury
if
the
powered
mobile
equipment
stops
or
startssuddenly,orintheeventofacollisionorupset.
Commentary about commercially manufactured
Ingeneral,acommerciallymanufacturedproducthasthefollowingqualities
(a) itisdesignedandbuilttosomestandardorgenerallyacceptedengineering
principlesthatmakeitsafeforuse;
(b) itisdesignedandbuiltbyperson(s)withtheskillorcompetencetobeabletomake
theproductsafe;
(c) itisproducedwiththeintentionofbeinggenerallyavailabletoanyonewhowants
tobuy
it
normally
there
is
an
exchange
of
money;
(d)itisnormallysupportedbythemanufacturerwithawarranty,guarantee,and
productsupport;and
(e) liabilityandsafetyissuesrelatedtoitsusehavebeenaddressedbythe
manufacturer.
ItisimpliedbytheOHSCode,thataproductthatiscommerciallymanufacturedis
safebecauseithasbeenproducedbyamanufacturerthathastheskillsand
competenciestodoso.
Criterion(a)
refers
to
the
product
being
designed
and
built
to
some
generally
accepted
engineeringprinciples.Itisexpectedthatamanufacturerisabletoprovide
drawingsorsketchesoftheproductthatincludeanassessmentoftheproducts
strength,loadbearingcapacity,etc.Further,criterion(d)mentionsproductsupport.
Thismayinclude,amongotherelements,theavailabilityofwrittenmanufacturer
specifications.
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Section 350 Suspended man baskets
Movedtosection75.1
Section 351 Boatswains chairs
Subsections 351(1) and 351(2)
Aboatswainschairraisedand loweredbymanuallypoweredhoistingequipment,
orusedwithadescentonlyriggingarrangement,shouldbedesignedtosupporta
minimum load of 113.7 kilograms (250 pounds).Generally, the chairwill have a
minimum 19millimetre(3/4 inch)thickplywoodseat,attachedatfourcornersby
minimum 13 millimetre (1/2 inch) diameter nylon rope to a master link, or be
constructedto
provide
aequivalent
strength,
and
have
alap
belt
to
secure
the
chair
totheworker. VariousdesignsofboatswainschairsareshowninFigure23.34.
Readersarereferredtosection349ofthisExplanationGuideforadiscussionofthe
termcommerciallymanufactured.
Figure 23.34 Various designs of boatswains chairs
Apowered(motorized)boatswainschairisapoweredplatformandmustmeetthe
requirementsofCSAStandardCAN3Z271M98 (R2004),SafetyCodeforSuspended
PoweredPlatforms(seesection348).
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Subsection 351(3)
While the anchor to which the rope is attached must have a strength of 22
kilonewtons (5000poundsforce), the ropemusthaveastrengthof27kilonewtons
(6000 poundsforce). The breaking strength of rope means the manufacturers
specifiedminimum
(or
nominal)
strength
of
new
rope
under
astraight
pull
test
condition.The5kilonewtondifferencebetweenropestrengthandanchorstrengthis
toallowforlossesinropestrengthduetofactorssuchastheropetermination(such
asknotsor splices), the rope runningoverpulleysorother small radius surfaces,
wearwithingenerallyacceptedlimits,anddeteriorationintheropefromregularuse
uptothetimewhenrejectioncriteriarequiretheropetoberemovedfromservice.
Subsection 351(4)
Noexplanationrequired.
Section 352 Temporary supporting structures
CSAStandardS269.11975(R2003),FalseworkforConstructionPurposes,providesrules
and requirements for the design, fabrication, erection, inspection, testing,
maintenanceanduseoffalseworkmaterialsandcomponentswheretheyareerected
toprovidetemporaryverticalsupportforbuildingsandotherstructuresduringtheir
construction,alterationorrepair.
Falseworkisthetermusedtodescribestructuralsupportsandthebracingrequired
to support temporary loads during construction. A fly form deck panel is a
complete,unitized falsework structure intended tobemovedasaunit.A formor
formworkisthemouldintowhichconcreteisplaced.
Ifanyof theconditions listed insubsection (3)arepresent,ormaybepresent, the
employer must have the resulting temporary supporting structure certifiedby a
professional engineer. The engineers certified specifications must contain the
informationlistedinsubsection(4).
Section 353 Fly form deck panels
Nooneis allowedtobeonaflyformdeckpanelwhileitisbeingflown.Inadditionto