Scaffolds in Construction.ppt

8/14/2019 Scaffolds in Construction.ppt

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Scaffolds in Construction


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0507

Session ObjectivesYou will be able to:

Understand the nature of scaffold hazards

Identify major types of scaffolds and theiruse

Erect, move, operate, inspect, and maintaina scaffold

Implement safe work practices, use fallprotection, and protect yourself from fallingobjects


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Scaffolding Accidents 9% of construction-

related fatalities

There are almost10,000 scaffold-relatedinjuries each year

Loose plank a commoncause of accidents

A third of scaffolds lackguardrails

About of workers arenot properly trained


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Common Hazards of

Scaffold Work Electrical contact with

scaffolds

Slips, trips, and falls

Falling objects (toolsand equipment)

Weather-relatedhazards such as rain,

ice, and snow


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Common Types of

Scaffolds Most Common

Welded Frame

Mobile (Rolling) Two Point Suspension (Swing Stage)

Less Common

Boatswains chairs and floats

Tube and Coupler

Interior Hung (Needle Beam)

Ladder Staging


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Welded Frame and Other

Supported Scaffolds Secure to the building to prevent movement

Each tier must be placed with stacking pins

or couplings Legs on bases must be placed on firm

foundation

Each scaffold tier must be cross-braced

Full guardrails at the 10-foot level


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Welded Frame and Other

Supported Scaffolds (cont.) Footings must support

loaded scaffold

Scaffold uprights mustbe plumb and bracedto prevent swaying

Install guys, ties, andbraces to prevent

tipping Supported scaffolds

with a height-to-basewidth ratio greater than4:1 must be tied to the

structure


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Mobile (Rolling) Scaffold Height must not exceed four times the

minimum base dimension

Must be fully planked, platform secured

Never ride on a mobile scaffold unlessspecific conditions exist

Lock in place when in use


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Mobile (Rolling) Scaffold(cont.)

The casters must be able to withstand four timesthe load of the scaffold, with positive lockingdevices

Each tier must be fully braced

The platform must have full guardrails if it is 10 feetabove the ground

Power systems used to move scaffolds must be

designed for that purpose Platforms must not extend beyond base supports

Scaffolds must be leveled using screw jacks orequivalent


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Two-Point Suspension

Scaffold Inspect before installation and during use

Roof irons or hooks must be securely

installed and anchored Suspension ropes must be able to handle

six times the rated load

The platform must not be more than 36

wide.


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Suspension Scaffolds in

General Support device must rest on surface that

can support four times scaffold load

Inboard ends of outrigger beams must bebolted to structure or supported bycounterweights

Tieback strength must be equal to

suspension rope strength The platform must be secured to prevent

swaying


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Suspension Scaffolds In

General (cont.) Each rope must support six times max load

Wire ropes must be inspected prior to

each work shift for: Kinks, bends, or other physical damage

Broken wires in the strands

Abrasion, corrosion, heat damage

Repaired wire rope cannot be used

Suspension scaffolds must have emergencyor automatic braking devices


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Types of ScaffoldsAny

Questions?Any questions about the types of scaffolds

used at our construction sites?


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Scaffold Capacity Each scaffold and component must be

designed by a qualified person

It must support its own weight plus at leastfour times its maximum intended load

It must be constructed and loaded accordingto the design criteria


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Access to Platforms Use a ladder or steps

for platforms more than2 feet above or below

point of access Climbing cross braces

is not a form of access

Use proper access

Hook-on ladders Stairways and

stair towers

Inclined ramps and

walkways


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Platform Construction Working platforms

must be fully planked

Most platforms must be

at least 18 wide

Must be within 14from face of work

Must extend at least 6

over support Cantilevered platform

ends must besupported or guarded


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Long PlatformsAbutted platform ends must rest on

separate supports

Common supports may be used forplatforms specifically designed for such use

Planks must be over supports andoverlapped at least 12 or secured

At corners, the overlapped plank that is notat a right angle must be laid under the plankthat is at a right angle to the support


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Platform Components Wood platforms must not be painted

Components from one manufacturer must

not be used with those of another system Components must not be modified

Components of dissimilar metalsmust not be used together


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Guardrail Systems Must be installed along open sides and

ends of platforms

Must be in place before scaffold is releasedfor use

Top height of guardrails must be between38 inches and 45(42 standard)

Top rails must be capable of withstanding200 pounds of force


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Guardrail Systems (cont.) Midrails must be installed between top rail

and platform

Screens, mesh, or solid panels may be used Midrail systems must withstand 150 pounds

Cross braces may be used provided they donot exceed a 19-inch opening

Guardrails may not present a puncture orlaceration hazard


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Protection from Falling

Objects Wear hard hats

Use toeboards

Use screens or panelswhen items arestacked

Canopies, debris nets,or catch platforms may

be used Barricade areas below

to protect fromoverhead hazards


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Scaffold Safe Practices Scaffolds must be erected, dismantled, and

altered under supervision of a competentperson

Inspect scaffolds before each work shift

Replace damaged or weakened scaffoldcomponents

Keep scaffolds away from energizedpower lines


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Scaffold Safe Practices (cont.) Do not load scaffolds beyond their rated

capacity

Do not move scaffolds horizontally while youare on them

Do not work on scaffolds that are coveredwith snow or ice

Do not work on scaffolds during stormsor high winds

Debris should not be allowed to accumulateon platforms


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Ladders on Scaffolds Ladders are prohibited except on large

area scaffolds

Ladders must be secured against sidewaysmovement

Platforms must be secured to the scaffold

Ladder legs must be prevented from

slipping off platform You are not permitted to stand on boxes or

other items


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Fall Protection Required when

working 10 feet abovea lower level

Use approved personalfall arrest system

Use guardrail system

Suspension scaffolds

require both


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Personal Fall Arrest

System Vertical lifelines must be fixed to anchor

independent of scaffold

Vertical lifeline must not be anchored to thesame point as suspension ropes

Horizontal lifelines must be secured to twoor more points of scaffold

Suspension scaffolds must be equippedwith additional support lines

Anchorage must support 5,000 lb


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Any Questions?Any questions about the safety

specifications of scaffolds?

Any questions about safe work practiceswhile working on a scaffold?


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Key Points to Remember Inspect the scaffold before each work shift

Properly secure platforms

Do not overload scaffolds

Wear personal fall arrest system

Understand scaffold hazards and followaccident prevention measures

Scaffolds in Construction.ppt

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