CONSTRUCTION SAFETY PART IIAVINASH KUMAR GUPTA

EE (TRANING)CCW

SCAFFOLDING• Temporary structures to support platforms as a

workplace/storage of materials.• prevent fall of workers and materials.• Properly constructed of sound material of

adequate strength to support weight and stress.• Securely anchored and stable• Erected ,altered or dismantled by competent

persons• Inspected at least once a week , written report of

inspection to be kept.

Independent tied scaffolds

An independent tied scaffold which does not rely on the building for itsstrength. It has inner and outer rows of uprights or standards

Independent tied scaffolds• It must be tied to the building but does not rely

on its strength.• Consists of uprights/standards, ledgers( parallel to

building),and transoms(90degree to building face)• Uprights be placed on firm and level ground, base

plates should rest on timber sole boards. Never use bricks, broken paving stones.

• Uprights to be equidistant, ledgers to be fixed inside ,joints in ledgers to be staggered. transoms on top of ledgers

continued

• For 38 mm boards ,transoms to be so spaced that no scaffold board overlaps more than 150mm or less than 50 mm.

• Ledgers and transoms should not project beyond the outline of scaffold to cause danger to pedestrian or passing vehicles.

• Bracing is essential to stiffen the scaffold.• Removing of bracing only within one lift if

required for passage of workers.

TIES

• Scaffold is to be tied to building to prevent movement /collapse.

• Area of scaffold should not be more than 32 sqm per tie.

Working platforms and gangways

• Each board should have three support to prevent bending or sagging.

• Where the ends of board meet, transoms must be doubled, no board overhangs four times its thickness.

• Width of platform ,i. 60 cm for footingsii. 80 cm for stacking of materials iii.110cm for supporting a trestle platform

Guard rails and toe boards

Working platform showing guard-rail and toe board with wire meshfilling between them and the closely boarded platform

Continued

• Where fall is more than 2m provide guard rails and toe boards

• Guard rails 90cm to 115cm , toe board 15 cm• Prevents falling accidents

Single pole/putlog scaffold

A single pole or putlog scaffold, with a single outer row of uprights orstandards and which is partly supported by the building

• For small jobs, platform resting on horizontal putlogs fixed at 90 degree to wall.

• Flattened inner of putlog rests on the wall/holes in the wall. Scaffold can not stand without support of structure.

• Mostly in use for brickwork.• Base plate of upright rests on timber sole board. Sole board to

support at least 2 uprights.• Uprights not more than 2 m apart, and 1.3 m from wall to support

5 board platform.• distance between ledgers not more than 2 m. Distance between

putlogs not to exceed 1.5m• Tying to building and bracing to full height is required.• Prevent children from climbing a scaffold after close of the working

day.

Protection From falling Materials

Protection of scaffold from fallingmaterials – scaffold fan and debrisnetting

continued

• Provide sheeting, boarding,netting, fans or brick guards to prevent materials falling from the scaffold into street or public place

DEBBIGUARD

Brickguard

• Mobile tower scaffold-wheels should belocked when in use; ladder access shouldbe inside the tower

Mobile TOWER

Tower Scaffoldo Consists of a platform resting on horizontal ledges connected

to four uprightso Devised for painters.o Accident happen when tower topples over.• Ratio of the height of the tower to the width of the base in

excessive.• Top of working platform is overloaded.• Ladder is placed on top of platform.• Mobile tower is moved with persons/ materials on top of

platform.• Tower is not tied to building.• Access to the platform is via outside of the tower.

Tower Scaffoldo Height – ratio of Ht : base, (indoor) 4:1≯

(outdoor) 3:1≯Static free Standing Height 12m≯

Mobile free standing 9.6≯Tied to building 12.0m≯

o Structure –• Vertical, single platform, firm & level base (base plates)• Corner standards 1.2m.≮• Caster wheels die 125mm.≮• Wheels with locks & breaks.• Breaks applied when stationery.

Tower Scaffoldo Platform – • Cover on the opening with a latch.• Handhold on cover.• Guard rails & toe boards.• Ladder inside.

o Movement – Never move when persons or materials on platform.

TRESTLE SCAFFOLD

A trestle scaffold suitable only for light work such as cleaning or painting

Trestle Scaffold• Light work of short duration

• Working platform 430mm inside.≮• 1/3 of height of trestles should be above

platform.

• When working platform > 2m, provide guardrail & toe board.

• Adequate bracing.

• Board 38mm, distance 1.35≯• Board 5mm distance 2.45m≯

SUSPENSION SCAFFOLD

Suspended scaffold

Suspension Scaffold- Tall buildings- Suspended platforms (hinged/ independent)- Cradles- Suspended form building/ structure by means of

outriggers, tracks and parapet hooks.

Accidents- Difficulties in getting in/ out- In sufficient counter weight/ secured.- Failure of ropes.- Poor maintenance.

UNSAFE Cradles

Safe cradles