Scaffold Construction

7/29/2019 Scaffold Construction

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By: Georgia Tech Occupational

Safety and Health Program

Scaffolding: Your Key to

Stability


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29 CFR 1926 Subpart L

1926.450 Scope and Application

1926.451 General Requirements

1926.452 Additional Requirements

1926.453 Aerial Lifts

1926.454 Training RequirementsAppendices A thru E


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Most Frequently Cited Hazards

Scaffolds above 10 ft.-Fall Protection

Scaffold Access

Scaffold Working Levels-Decked

Aerial Lift-Harness/Lanyard

Training in use of scaffolds


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National Statistics

A significant percentage

of personnel in

construction (65) work

from scaffolds routinely

There are approximately

50 fatalities related to

scaffolds each year.

There are approximately

4500 employee injuries

each year as a result of

using scaffolds.

For the period 1980-1985

falls from scaffolds

accounted for 17% of the

fatalities for falls fromelevations.


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Georgia Statistics

The total number of fall related fatalities in

2000 was 25.

The number of fatalities involving scaffolds

were 6.

Falls from scaffolds represented twenty five

percent of the total fatalities in the state


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Hazards

Injured workers revealed that 72% of the

accidents were caused by:

Platform failure

Support failure

Slipping

Being struck by an object


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Requirements for Competent

Person A competent person is a person on the

project who has knowledge to identify and

the authority to correct site hazardsOSHA 10 or 30 hour training card could

support the fact you had training and areknowledgeable

The 10 or 30 hour OSHA training card alonedoes not necessarily mean you are a competent

person


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Requirements for Competent

Person Scaffolds have to be inspected daily by a

competent person

Scaffolds must be erected, moved,

dismantled or altered under the supervision

of a competent person

Work by qualified workers selected by thecompetent person


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Capacity 29 CFR 1926.451(a)

Each scaffold and scaffold component must

be capable of supporting four times the

intended weight.

Direct connections to the roof and

counterweights of suspended scaffolds must

resist four times the tipping moment or 1.5times tipping moment imposed by scaffold

operating at stall load


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Capacity 29 CFR 1926.451(a)

Suspension ropes including hardware must

support six times the maximum intended

load

The stall load of any scaffold hoist shall not

exceed three times its rated load.

Scaffolds must be designed by a qualifiedperson and loaded accordingly.


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Platform Construction 29 CFR

1926.451(b) All working levels of scaffolds are required

to be fully decked.

No gaps greater than one inch allowed

Each scaffold platform shall be at least 18

inches wide.

Ladder jack, roof bracket and pump jack can be12 inches wide.


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Platform Construction 29 CFR

1926.451(b) The front edge shall not be more than 14

inches from face (if in excess rails

required).

The end of each platform will extend over

the center line by six inches (unless

hooked).


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Platform Construction

Requirement for overhang based on length:

10 ft or less platformnot to exceed 12 inches

More than 10 ft not toexceed 18 inches

For extended

platforms overlap oversupports by 12 inches(unless secured)

Wood platforms shall

not be covered with

opaque finishes. Components

(different) shall not be

mixed unless they fit

(integrity maintained).


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Supported Scaffolds, 29 CFR

1926.451(c) Scaffolds with a width to height of more

than 4:1 need to be restrained

Guys, ties, and braces installed in

accordance to manufacturer

Ties, guys, wires must be used for eccentric

load


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Supported Scaffolds, 29 CFR

1926.451(c) Supported poles, legs, and posts need to

bear on base plates and mudsills or other

firm foundation. Footing must be rigid and sound.

No unstable objects for supports or

platform. Legs, posts, frames must be plumb andbraced to prevent swaying.


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Scaffold Access, 29 CFR

1926.451(e) When scaffold

platforms are 2 feetabove or below a pointof access ladders, stairtowers or personnelhoist must be used.

Cross braces can not be

climbed. Ladders set up so not

to tip scaffold.

Stairway type ladders

can be used in

1926.451(e)(3) Railing has to be

provided

Ramps 1926.451(e)(5)

Rails over 6 feet

No slope greater than

20 degrees


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Scaffold Access

Integral prefabricated

scaffold access

frames: Designed and

constructed as ladder

rungs

Rung length of 8inches

Uniform space

Direct Access shall only

be used when scaffold is

not more than 14

horizontal and 24 verticalaway.

Safe means of access shall

be provided during

erecting or dismantling asdetermined by competent

person.


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Scaffold Use 1926.451(f)

Scaffolds shall not beexcessively loaded

Inspection by competent

person before each shift Damaged scaffold

immediately repaired orreplaced.

Maintain adequatedistance from power lines(3 ft for less than 300 Vand 10 ft for greater than300)

Must not work on

slippery platforms,

debris or during highwinds.

Standing on objects to

increase height

prohibited.

Ladder may be used

on wide area scaffold.


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Scaffold Use

Scaffolds must be inspected before use each

shift by competent person.

All damaged components must be repairedor replaced immediately.


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Fall Protection, 29 CFR

1926.451(g) Required on all

scaffolds greater than10 feet.

Boatswains chair,floatscaffold or similarrequire fall arrest.

Suspension scaffoldrequires rails and fallarrest system(independent life line).

Rail system design:

Top rail installed between

38 and 45 inches

mid rail between top andworking surface

Finished components

must with stand:

A force 200 pounds for toprail

150 pounds for mid rail


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Fall Protection

Guardrails must be free ofsharp edges.

Ends of rails must be

constructed so it doesoverhang the terminal

posts

Steel or plastic bands arenot acceptable as railing

Cross brace may be usedas a mid rail if it meets theheight requirement (cross

between 20-30 inches)

Falling objectrequirements are:

Employees on scaffold(in

addition to hard hats) mustbe protected by toe boards,debris nets or canopy

Area below must beprotected by barricades,canopies, toe boards on

scaffolds over 10 feet

Toe boards- withstand 50pounds of force and be 3.5inches wide.


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Additional Scaffolds-

Supported, 29 CFR 1926.452 Tube and coupler:

The existing platform

shall not be moveduntil bearers are set

X bracing installation

Couplers have to made

of structural steel Scaffolding over 125

ft. have to be designed

by registered engineer

Fabricated Frame:

The existing platform

shall remain until theframes are set/braced

Frames and panels

shall be braced (joined

with stack pin

Scaffolding over 125

ft. have to be designed

by registered engineer


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Additional Scaffold-Supported

Horse scaffolds:

Limited to two tiers (10 ft.)

Horses arranged directly

over each other

Legs nailed down and tiers

braced

Crawling boards:

Extend from peak to eavesand secured to roof by ridge

hooks or equivalent

Pump jack scaffolds:

Bracket must have twopositive grips

Poles secured at the top andbottom

Work bench is not aplatform

Continuous length polesjoined at seam parallel to

bracket

Mending plates must beinstalled at 2X4 splices forstrength


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Additional Scaffolds-Supported

Ladder jack scaffolds:

Not to exceed 20 feet

Ladder meet requirement of

part X

No bridging of platform

Ladders must be provided

with device to prevent

slipping

Constructed to bear on side

rails and rungs or rungs (if

rungs at length of 10

inches)

Window jack scaffold:

Attached to window

opening and not used to

place planks betweenscaffolds

Step, trestle, and ladder

scaffolds:

Platform not placed higher

than second highest rung

and ladder secured

Ladders designed to part X


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Additional Requirements-

Suspended Swing Stages:

Platform limited to 36

Platform must be securely

fastened to hangars

Platforms shall be of the

ladder, plank, or beam type

Two point scaffolds shall

not be bridged together

unless bridged and hoist isappropriately sized

Multi level scaffolds:

Equipped with

independent support

lines (equal to number

of suspension points)

and not attached to the

same point as

suspension ropes

Supports for platform

attached to stirrup only


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Additional Requirements-

Mobile Requirements for mobile

scaffolds:

Adequately plumbed,

braced, level and squared

Must have means to lock

wheels/casters

Force to move scaffold no

higher than 5 feet above

support surface

Power system must be

designed for scaffold

Stabilized to prevent tip

Platform must not extendbase support without

outriggers Caster stems-pinned

Riding not allowed unless:

surface floor level and freeof debris and 2:1 BXH ratio

Outriggers on both sides

No one allowed onextended platform


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Additional Requirement-Stilts

Only to be used on large area scaffold

Surfaces must be flat and free of pits

No obstructions

Stilts have to be maintained

Guardrails must be raised by an amount

equal to stilts


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Requirements for Aerial Lifts

29 CFR 1926.453 Meet the design criteria of

ANSI

Aerial ladders must be

secured in lower travelingposition by a lockingdevice before it is moved.

Ext./Art. Platforms:

Boom must be adequatelystowed before move

Insulated portion must notbe altered

A body belt or harness and

lanyard must be used

Employees must stand on

floor of basket Never exceed load capacity

Lift truck shall not be

moved with men in basket

unless adequately designed

(upper controls-personnelcarriers)

Brakes set for outrigger use

(wheels chock)


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Aerial Lifts

Extensible and articulating platforms:

Lift controls must be tested each day

Authorized employees only

No belting off to adjacent structure

All pneumatic and hydraulic components

comply with ANSI A92.2-1969 and noncritical parts must have burst factor 2:1.


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Training-General

29 CFR 1926.454 Employees must receive training from

qualified person that includes:

Nature of electrical, fall, and falling itemsUse of scaffold/handling

Maximum intended load and load carryingcapabilities of scaffold

Methods for dealing with electrical hazardsand fall protection system

Requirements of sub L


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Training-Setup or Dismantling

Employees must be trained in:

Nature of scaffold hazards

Procedures for setup, dismantling or movingthe system

Design criteria, maximum intended load

carrying capacities and use of scaffoldRequirements of subpart L


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Training-Need for Retraining

When the employer has reason to believe an

employee lacks the skill or understanding needed

for safe work involving scaffolds, retraining shallbe performed until proficiency is regained.

Retraining is required:

When additional or new hazards exist.

Changes in the type of scaffold and fall protection exist. Where there are inadequacies in an employees work.


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Resources

www.osha.gov

29 CFR 1926.451

NAHB-OSHA Job Site Safety Handbook

Construction Industry Digest

Scaffolding Industry Association

www.scaffold.org

American National Standards Institute A92 (SIA): Scaffolds and other elevating devices

Documents

Scaffold Construction