Construction ActivitiesHazards and Control

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Construction Activities

Learning outcomes:

1. Identify the main hazards of construction and demolition work and outline the general principles to control them;

2. Identify the hazards of work above ground level and outline the general requirements necessary to control them;

3. Describe the safe working practices for common forms of access equipment;

4. Identify the hazards of excavations and outline the general requirements necessary to control them; and

5. Identify the hazards to health commonly encountered in small construction activities and explain how risks might be reduced

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Construction Activities

General

1. Scope

2. Stacking and storage – Stacked goods– Storage - general– Storage of flammable and combustibles

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(Stacked goods)

Kept as small as is practical, adequate space, and should be vertical.

Kept away from walls and off the floor by using pallets.

Should not block light, obstruct fire detection and control equipment or block drains.

Separate stack for different types of containers.

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(Storage – general)

Should not be used for other work activities. Adequate space for movement (access and egress). Kept clean and tidy. Mixed storage : materials should be separated for easy location and

access. Incompatible materials should not be stored

together.

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(Storage – general)

Warning signs for any special danger or any special precautions measure.

Adequate fire protection. Should not permit public access.

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(Storage of flammable and combustibles)

“Require special storage arrangements”

Additional requirements: Should not be stored with other materials,

separate stores for liquids, solids and gases, oxygen cylinder stored separately away.

External open-air store (fenced)– 3 meters from other buildings or activity.

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(Storage of flammable and combustibles)

Internal stores – of fire resistant material with good level of ventilation.

At least 2 exit for fire escape and shut / locked when not in use.

Marked with hazards and precautions information. Fire risk activities should not be carried out close to

storage area unless with suitable PPE.

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(Storage of flammable and combustibles)

Electrical equipment in store must not be a potential source of ignition.

Fire fighting equipment and system must be in good condition.

Inspected regularly, planned maintenance, and good housekeeping.

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Construction Activities Risk factors and risk activities

Main hazards and controls

1. Machinery and vehicles

2. Site security

3. Electricity

4. Slips, trips and falls

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1. Machinery and vehicles

Machinery hazard: Contact with moving parts, dust, noise, vibration.

Control: Warning signs, guards, segregate areas,PPE. Vehicle hazard: toppling over, collision with pedestrian,

other vehicle, structures-collapse. Control: Keep people and vehicle separate (sites & building

entrance) Traffic routes Visibility Stationery vehicle safety procedure.

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2. Site security

Site Hazards: Public access, vandals, thieves, children. Control: Entrances locked. Fencing – 2 meters high. Other protection measures: Not leaving ladders lying around. Disabling equipment. Covering excavations. Securely locking tools and hazardous substances at

night. Provide security staff, cctv, lighting and alarm.14

3. Electricity

Electrical Hazards: trailing cables, live wires exposed, unsafe equipment, overhead power lines, buried cables.

Control: Identify buried cable position. Provide guards Segregate areas Equipment properly maintained Incorporate circuit breaker on equipment Use low voltage circuit Substitution other form of power (eg: compressed air)

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4. Slips, trips and falls(working at height and excavation)

Hazards: Uneven & muddy floor, trailing wire, holes, falling items.

Control: Proper manual handling PPE

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Management Controls

Planning for Health and Safety Documentation Selection of Contractors Control of Contractors on Site

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Construction Activities

Working above ground level (Over 2 metres)

Basic Hazards:

1. Roof (fragile roof- use roof ladder/crawling boards)

2. Deterioration of Materials

3. Unprotected Edges

4. Unstable Access Equipment

5. Weather

6. Falling Materials 18

Construction Activities

Main precautions to prevent fall and falling

material:

1. Guard rails, fencing and toe boards

2. Working platforms

3. Ladder hoops

4. Fall arrest equipment

5. Protection against falling materials

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1. Guard rails, fencing and toe boards

Mid rail

missing

Toe boards

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2. Working platforms

Basic Requirements: Sufficiently wide. Capable of bearing loads. Supporting framework should be stable. Closely boarded to prevent gaps.

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3. Ladder hoops

Prevent falling from height but do not prevent sliding down the ladder.

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4. Fall arrest equipment

Boatswain’s Chair

- Light short term work

Safety Harness

-Use when approaching open edges

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Protection against falling materials

Not stacking materials near edges. Close boarding of working platforms. Using hoist to lift or lowering down materials.

or (protect people) Covered walkways. Sheeting across scaffold. Netting to catch falling material. Designated exclusion zone.

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Safe Working Practices for Access Equipment

Independent Tied Scaffolds Mobile Towers Mobile Elevating Work Platforms (MWEP) Ladders Cradles

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Independent Tied Scaffolds

Scaffolding basic components: Standards Ledgers Transoms Designed to carry its own mass, material load,

and workers load (use of base plates). Tied to a building for stability. Bracing is used to stiffen scaffold framework.

(eg: Façade bracing & Ledger bracing)26

Mobile Towers

Used for painting and simple maintenance job. With working platform and four wheels. Height limited to 12 metres. Safety points: Do not remain on top when being moved - easily

overturn. Unstable on rough grounds. Avoid obstacles. Lock wheels when not in use.

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Mobile Elevating Work Platforms (MEWP)

Precautions: Firm sound ground. Sufficient clearance. Barrier to avoid

collision. Edge protection for

work platform. Controls of arm inside

the cradle.

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Ladders

Grade 1 – light work Grade 2 – medium use Grade 3 – heavy duty work Metal ladders not be used near unprotected live

electrical circuits Must be set on solid flat base Angle 75 degree Top rest against solid support. Only one person climb the ladder at a time Nothing should be carried while climbing

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Inspection of Scaffolds

Inspect at regular intervals (once per week). Inspect when first erect. Things to check: Tying and bracing Edge protection Ground condition Access Loading

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Construction Activities

Excavations hazards

1. Falling in

2. Collapse

3. Buried services

4. Flooding

5. Hazardous substances

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Construction Activities

Excavation precautions/ controls1. Battering and shoring2. Barriers3. Access ladders 4. Crossing points (gangways)5. Lighting and warning signs (prevent people falling)6. PPE 7. Check for buried services 8. Proximity of vehicles (exclusion zone: barrier,warning

signs,lights)9. Inspections (daily)

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Construction Activities

Related health hazards1. Noise and vibration2. Dust3. Asbestos4. Cement5. Solvents6. Cleaners

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Construction Activities

Summary and revision

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Revision Question

1. What are the requirements for mixed store?

2. What are the requirements for the internal storage of flammable materials?

3. What are the safe method of working on fragile roof?

4. What are the main hazards of using ladders?

5. What measures should be taken to prevent materials from falling from a height?35

Revision Question

6. In respect of scaffolding: What is the difference between standards,

ledgers and transoms? What is the difference between tying and

bracing?7. State the safety precautions which need to

be taken when mobile elevating work platforms are in use.

8. What is the angle at which ladders should be positioned?

9. When should scaffolding be inspected?36

Revision Question

10. Identify the main hazards associated with excavation work.

11. What is battering?

12. What are the key elements of shoring?

13. Identify the requirements for crossing points.

14. How can the hazards of buried services be avoided?

15. When must excavations be inspected?37