safety in formwork

7/30/2019 Safety in Formwork

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Safety

inFormwork

by : Hemant Kadu


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Fall of Object

Electrocution

Transport vehicle

MiscellaneousHigh Incidences of Accidents

while working at Height

08%

11%

16%08%

Fall of Person

57 %


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Falls in Construction

Falls are the leading cause of deaths in the constructionindustry.

Most fatalities occur when employees fall from open-sided floors and through floor openings.

Falls from as little as 4 to 6 feet can cause serious lost-time accidents and sometimes death.

Unguarded open-sided floors, periphery and platforms 6feet or more in height led to many accidents.


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Scaffolding

A temporary structure that supports oneor more platforms;

Support workmen, plant and materials

during:

Construction

Maintenance

Repairs &

Demolition


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Scaffold Safety

Pole/ Post/Standard

Runner/Ledger

Cross BracingSole Plate

Base Plate

Bearer

Longitudinal Bracing


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Independent Scaffold

Pole/Post/Standard

Bearer

Cross Bracing

Runner / Ledger

Sole Plate

Base Plate


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3 basic types:

Supported scaffolds:

Platforms supported by rigid, load

bearing members, such as Standards,

legs, frames, & outriggers etc.,

Suspended scaffolds: Platforms

suspended by ropes or other non-

rigid, overhead support

Aerial Lifts -- such as Boom trucks

Types of Scaffold


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Scaffold Specification(OSHA)

Light DutyMedium

Duty

Heavy

Duty

Uniformly Distributed Load

25 psf

122kg/m2

50 psf

244kg/m2

75 psf

366kg/m2

Transverse distance between Posts1.8m 1.8m 1.8m

Longitudinal Distance between Posts3.m 2.4m 1.98m

Vertical distance between Runners

(Ledgers) 1.8m 1.8m 1.8m


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Cross or Transverse Bracing

Cross bracing shall beinstalled across the widthof the scaffold at everythird set of Poles and

every forth Runnervertically.

Such bracing shall extenddiagonally from the innerand outer runners upwardto the next outer andinner Runners

Pole/Post/StandardBearer

CrossBracing

Runner/Ledger

Sole Plate

Base plate


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Longitudinal Bracing

Longitudinal diagonal bracing on theinner and outer rows of poles shall be

installed at approximately a 450 angle

from near the base of the first outer post

upward to the extreme top of the

scaffold. Where the longitudinal length of

the scaffold permits such bracing shall

be duplicated beginning at every Fifth

Post.

In a similar manner longitudinaldiagonal bracing shall also be installed

from the last post extending back and

upward toward first post.

Pole/PoStandarBearer

CrossBracing

Runner/Ledger

Sole Pla

Base plate


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Tying to Structure(OSHA)

The entire scaffold shall be tied securely against the building at

intervals not exceed 30 feet horizontally and 26 feet vertically.

Tied Post

Tied Post


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Plan Bracing

In places, where tying to structure is not possible Plan Bracing can be providedas shown

(IS 3696 (Part 1) 1987)


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Tying to Structure

Tie through Opening Scaffold fixed to Form ties


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Cross or Transverse Bracing

Tie around a Column


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Tubular Frame Scaffold

(OSHA)

Designed to support 4 times the maximum ratedload.

Braced by cross bracing or diagonal braces or both.

Set on adjustable bases or plain bases. If load bearing capacity of soil less base to be set on

sole plate.

Each such joint to have a coupler two stacking pins

Secured to the structure at Intervals not to exceed9m (30 feet) horizontally and 8m (26 feet) vertically.

Scaffolds above 38m (125 feet) height shall bedesigned by a Professional Engineer


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Mobile Scaffold


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Mobile Scaffold

When free-standing height not exceed four timesthe minimum base dimension.

To support four times the maximum intendedload.

All wheels shall be provided with a positivelocking device

To be braced by cross bracing or diagonalbraces or both

Platforms shall be tightly decked secured againstdisplacement.

Platforms shall be provided with guard rail


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Mobile Scaffold

The force to move the scaffold to be applied asclose to the base as practicable

To be moved only on level floors free fromobstructions and openings.

The wheels to be provided with rubber or similarresilient tires

Workmen not to be allowed to ride on mobilescaffold.

All materials to be removed before mobile scaffoldis moved.

Wheels to be locked while scaffold in use.


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L&T System Scaffolding


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Erection Sequence

After compacting & leveling

the ground, mark the longer

& shorter span dimension of

2.250 m & 1.525 m using

measuring tape.

Place the foot plate atmarked position


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Erection Sequence

Assemble the tower spindle with foot

plate using spring locked pin

Place the tower spindle with foot

plate using spring locked pin at all the

four legs of tower


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Erection Sequence

Erect the basic frame

1.80 Erect the basic frame 1.80

at other end


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Erection sequence

Place the bracing H-225

between the Basic frame

Place the Diagonal bracing

D-18.225 at the samedirection


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Erection Sequence

Place the horizontalbracing H-225 between

the basic frame at upper

level

Follow the SameSequence of Placing of

the Bracings at other end


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Erection Sequence

Place the plan bracing

D-12.225 to check the

diagonal of tower at top

level

Check the level of Towerusing water level


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Erection Sequence

Align the tower using line

thread

Place 3 nos of Scaffoldboard top of tower


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Erection Sequence

Tie the safety belt at top

of the basic frame

Insert the HD coupler

top of the basic frame

using spring locked pin


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Erection Sequence

Insert the HD coupler top of thebasic frame using spring locked

pin all the four legs

Erect the second unit of basicframe 1.20


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Erection Sequence

Erect the basic frame 1.20 atother end and insert the

spring locked pin at 4 legs

Place the diagonal bracing

D-12.225 and Horizontalbracing H-225 between the

basic frame 1.20


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Erection Sequence

Repeat the said

procedures.


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View of the tower after

Erection


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Foundation Formwork

Care to be taken while

lowering the components into

the excavated pit

Formwork components to be

stacked at a Safe distance to

prevent falling of the

components and sand slideinto the excavated pit


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Wall / Column formwork

Good Rigging Practices to befollowed while lifting the formwork

assembly

Strength and Location of lifting

hooks on the formwork to be

checked

Panels to be pre-checked for

defects or damages before lifting

No loose materials to be kept on the

formwork panels or platforms whilelifting the panel


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Flex System

All the main props to be fitted

with Tripod

All the intermediate props to

be fitted with supporting head In ground level work, proper

earth compaction and

necessary bearing below the

prop shall be given


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Heavy Duty Tower

Every 6m interval (vertically)

bracing to be fixed with

permanent structure or from

one tower to the other.

Ground level earth to be

compacted well for better

loading


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Stair Tower

Ground level earth to be

compacted well

Every 6m interval (vertically)

bracing to be fixed withpermanent structure

Coir rope / binding wire not to be

used in place of M10 bolt

Bracings & lock pins not to beomitted under any circumstance


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Access Scaffold

Ground level earth to becompacted.

The system to be braced atevery 6m-height level with thepermanent structure.

Old / damaged components notto be used.

Coir rope / binding wire not to beused in place of Platform hanger

Bracings not to be omitted under

any circumstance.


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Lift Shaft Formwork

Proper Slinging and Rigging Practices to be

followed while lifting the formwork assembly

Strength and Location of lifting hooks on the

formwork to be checked

No loose materials to be kept on the formwork

panels or platforms.

Panels to be pre-checked for defects/damages

before lifting

Adequate space (gap) to be ensured before lifting

the inner panel platform


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Slipform

Provision for Earthing andRCCBs of 30mA sensitivityfor electric power supply

Lightning arrester

Aviation Light

Communicationarrangement

Safety aspects in Hoistand Winch

Bracing of access tower atevery 6m height

Handrail and toe board inthe platform

Safety nets to trap thefalling materials

Adequate illumination

Fire Extinguishers

Workmen entry register


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Collect & stack required components &

tools nearby work place

Stacking of Materials


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Hazards / Risks

Failure to secure the scaffold to thebuilding;

Inadequate bracing; Failure to brace it adequately;

Inadequately supported scaffold board;

Erected on uneven ground;

Use of unsuitable or faulty materials; Absence of suitable number of couplers;

Inadequate access or unsecured ladder;

Scaffolding


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Inadequate or irregular platform width;

Overloading of platform and scaffold;

Use of makeshift materials;

Gang ways obstructed.

Absence of toe boards and guard rails wherenecessary;

Absence of good drainage system near the standardsto prevent erosion.

Hazards / Risks


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Precautions to Be Taken

Surface - firm, level and compacted;

Sole plates below the base plates;

Sole plate shall rest on at least two vertical pipesand should extend 600 mm beyond the vertical

pipes; Staging braced at every height of 6 m;

Sufficient diagonal bracing.


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Scaffolding

Erection


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Scaffolding

Erection

By skilled workmen with the supervision of a

competent Supervisor.

Cordoning the area. Lifting of frame and other parts by the use of

Derrick & Pulley arrangement

Ladder shall be used for climbing up and down.

Red Tag shall be provided to caution that thescaffold is under erection


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Scaffolding

Erection

At the end of the day, if a scaffold is going to be left

half-erected, it is essential to lower all the loose

scaffold materials down and ensure that the scaffoldis braced adequately to the building/structure.

Double Lanyard Safety Harness shall be used by all

workmen engaged in scaffold erection works.


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Dismantling of Scaffolding

Dismantling only by Skilled Workmen

Cordoning of the area

Red Tag to be displayed

Lowering of the materials by the use of Derrick and

Pulley arrangement

Each tier shall be completely dismantled and the

material lowered to the ground before beginning to

dismantle the next tier

Materials not to be dropped


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Dismantling of Scaffolding

Double lanyard safety harness to be anchored to astrong structure or lifeline before attempting toloosen stuck or jammed parts

At the end of the day, if a scaffold is going to be lefthalf-dismantled, it is essential to lower all the loosescaffold materials down and ensure that thescaffold is braced adequately to thebuilding/structure

All the dismantled materials shall be stacked in theappropriate manner at the designated place

COMMON FAULTS IN


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COMMON FAULTS IN

SCAFFOLDING

Supporting of boards inadequate and therefore

liable to tilt.

Erected on uneven ground.

Couplermissed.

Absence of ties where necessary.

Inadequate access.

Not wide enough - minimum two plank. Gang ways obstructed.

Absence of guard rails where necessary.

S ff ld T S


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Scaffold Tag System

Date of Inspection:

Signature of Competent Person

Date of Inspection :

Signature of Competent Person


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Scaffold Tag SystemRed Tag

This tag indicates that the scaffold is undererection or dismantling or has not been

inspected or is not safe for use (by anyone

other than scaffold gang).

Green Scaffold Tag

This tag indicates that the scaffold is

complete & it has been inspected by

competent person and is safe for use.GREEN scaffold tag is valid for one week

from the date of last inspection.


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WORKING PLATFORM


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Work-Platform


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Working Platform

Designed to support the weight of the personnel andequipment to be used.

Fully decked with scaffold boards.

Scaffold boards to be secured against displacement.

Erected on stable scaffold.

Provided with a ladder or any other safe means ofaccess.

Provided with guardrail:

Height of the top rail between 900 mm to 1200 mm.

Toe guard to be of minimum 100mm height.


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Working Platform

Midrail to be provided halfway between theplatform and the top rail

Toe guard shall be of minimum 100mm height

Posts and rails shall be capable of withstanding aforce of at least 900N applied at any point, or

withstanding any load likely to be applied Barriers to be provided on open edges, holes and

openings in the platform.

The minimum width of Working Platform shall be

as follows, Only Workmen: 600 mm Men, tools & materials: 900 mm

Men, tools, material & wheel barrows: 1200 mm

S ff ld B d


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Scaffold Board

F D t


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Few Donts

Unguarded Edge


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Unprotected sides and edges must have guardrails orequivalent

Unguarded Edge

Sid & Ed I t ti


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Sides & Edges - Improper protection

This 1/4" nylon rope alone is not a proper wayto guard this open floor

Fl O i


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This opening could be made safe by using aguardrail, or strong cover

Floor Openings


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Cover completely and securely

If no cover, can guard with a guardrail

Improperly covered Floor Openings

Few Donts


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Few Don ts


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Few Donts


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Few Donts


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Few Dos


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Few Dos


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Fall Protection

S f t B lt


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Safety Belt

Lanyard Anchorage

Point

Max Free

Fall Allowed

1.8 m

2 m or

more

Ground Level or Level

of adjacent surface

Full Body harness /

Waist Safety Belt

For more than 2.0 m height

Lanyard to be anchored to a fixedpoint

Free-fall not to exceed 1.20 m

Lanyard not more than 2 m.

Full Body Safety Harness


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Full Body Safety Harness(IS 3521 :1999)


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Working near floor Edge & Opening

Rope Grab Fall Arrester


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Full Body

Harness

Class -L

Ladder

Rope

Grab Fall

Arrestor

Vertical

Life Line

Rope grab fall arrestors used during vertical

movement such as ascending ordescending Scaffold towers, vertical ladders

etc.



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Rope grab fall arrestors used to protect fallof workers during vertical movement such

as ascending or descending Scaffold

towers, vertical ladders etc.


Lif Li


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Life Line

AnchoragePoint

Usage of lifeline

SupportLanyard

Full Body harness /

Waist Safety Belt

Life Line

20mm diameter polypropylene rope or 8 mm wire

rope Anchorage capable of supporting at least 2264 kgf

Anchored to strong points

The sag of the life line shall not be more than 15degree

R t t bl T F ll A t


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Retractable Type Fall Arrester

Retractable Fall Arrester


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Retractable Fall Arrester

Retractable fall arrestors shall be

used in places where high risk of fall

of workmen persists.

This fall arrestor can be directly

anchored to the anchorage or can be

used in conjunction with a lifeline

Safety Net


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Safety NetSafety net protects

Person from falling

Protect person working below

Safety net distance should not exceed 7.5 m

Net shall extend

up to 1.5 m 2.40 m 1.5 to 3.0 m 3.00 m

> 3.0 m 4.00 m

Person from falling

Tie cord at every 1 m

Border rope to withstand 5000 lbs (2268kg)

Drop test - 180 kg from 1 m above the workingarea


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Does & Donts

About

H.D. & L.D. TOWER


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