OSHA-Scaffolding Desig

7/29/2019 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.


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


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.


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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23-19

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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23-20

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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23-21

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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23-22

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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23-23

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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23-24

Figure 23.11 Commercially manufactured aluminum plank


termcommerciallymanufactuered.

Section 337 Needle-beam scaffolds

Figure23.12showsatypicalneedlebeamscaffold,highlightingseveralofthedesign

detailsthatmakethescaffoldsafeforuse.

Figure 23.12 Needle beam scaffold and design details


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23-25

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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23-26

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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23-27

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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23-28

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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23-29

AsshowninFigure23.20,stopboltsmustbeinstalledattheouterendsofthrustouts

topreventshacklesfromslippingoffthethrustouts.

Figure 23.20 Stop bolts at end of thrustout



Section 342 Swingstage scaffolds

Figure23.21 showsaswingstagescaffold inuse. Ifaswingstagescaffoldhasbeen

designed by a professional engineer rather than manufactured commercially,

operatingprocedurescertifiedbyaprofessionalengineermustbedeveloped.




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23-30

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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23-31

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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23-32

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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23-33

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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23-34

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


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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23-36

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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23-37

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:




(d)specialwarnings,cautions,orrestrictionsnecessaryforsafeoperation,including


(e) theoperatinginstructionsandanoticeindicatingtheneedtoreadtheoperating

manualbeforeuse.


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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23-39

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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23-40

Figure 23.28 Examples of manual elevating platforms

The Standarddoesnot require the platform tobemarked as complyingwith the

Standard.However,apermanentplatemustbelocatedontheplatformthatlists:




(d)themaximumhorizontalreach;

(e) specialwarnings,cautions,orrestrictionsnecessaryforsafeoperation,including


(f) theoperatinginstructionsandanoticeindicatingtheneedtoreadtheoperating

manualbeforeuse.


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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23-41

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


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.



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

Documents

OSHA-Scaffolding Desig