1. Samuel Nii Tettey (Ergonomist)
DEMOLITION
Samuel Nii Tettey
(Ergonomist)

2. MODULE OBJECTIVES Identify hazards of demolition
Outline control measures for demolition
Importance purpose and scope of pre-demolition survey

3. DEFINITION
Demolition – the deliberate destruction, pulling down, dismantling or taking apart of a structure (being it a building, quay, wharf, steel structure, etc.)

4. DEMOLITION METHODS
Piecemeal Demolition
Deliberate Control Collapse

5. PEACEMEAL DEMOLITION
Hand-held tools or machines are used for the demolition exercise

6. Techniques available for Piecemeal Demolition
Tools involve include: -
Pneumatic hammer
Hydraulic or electric hammer
Tooth grapple
Ball and chain
Non-explosive blasting
Hydraulic bursters
Thermic lance
Flame jet piercing
Water jet

7. TOOLS
Hydraulic/electric hammer
Pneumatic hammer
Tooth Grapple

8. TOOLS
Ball and Chain
Tool grapple

9. DELIBERATE CONTROL COLLAPSE
Use of explosives or structure pre-weakening
Followed by remote mechanical demolition or wire-pulling

10. APPROPRIATE METHOD SELECTION
The correct method to use is determined by pre-demolition survey
Apart from the two methods earlier mentioned, the following methods can also be considered
Pre-Weakening
Progressive Demolition
Overturning by Wire Rope Pulling

11. DEMOLITION HAZARDS Premature collapse Falls and falling objects
Plant, vehicles and equipment Overturning
Manual Handling
Dust and fumes
Noise and vibration
Service lines
Hazardous Substances
Dilapidated structures

12. PREMATURE COLLAPSE Main cause of demolition accidents
Due to lack of planning in the demolition exercise

13. FALLS AND FALLING OBJECTS
Due to poor access and egress
Unstable traffic routes
Unsafe structure
Work at heights

14. PLANT, VEHICLES AND EQUIPMENT
Poor, unstable and uneven ground
Poor control of vehicle movements
Use of unstable plant or vehicles
Unauthorised use of vehicles and plant by untrained operators
Proximity of road
Vehicles left in inappropriate places

15. MANUAL HANDLING High risk for MSDs due to poor MH and poor postures
Control
Mechanisation
Lifting and handling aids – trolleys, forklifts, wheelbarrow, etc.
Correct choice of equipment
Lighter loads
Avoidance of repetitive handling and awkward movements

16. DUSTS AND FUMES Dusts generated during demolition
Vehicle movements may also stir up dusts
Dusts may be irritant, toxic, corrosive
Dust contain silica compounds and asbestos
Fumes generated by heating and melting metals during welding

17. OTHER HAZRDS
Noise and vibration – hazard to workers and nuisance to communities
Service lines – to be identified to avoid fires, explosions, electrocutions
Hazardous substances - Chemicals, including lead based paints, PCBs, flammable materials, biological contaminants
Dilapidated structures - Empty and unused buildings falling into disrepair and holds, voids and services are not easily identified

18. DEMOLITION HAZARD CONTROL MEASURES
Avoidance of Premature Collapse
Consider structural stability
Provide temporary structural supports – shoring, propping, etc., scaffolding, acro-props, buttresses
Regular inspection of all fixings during the work

19. FAÇADE RETENTION SYSTEMS
Installed as demolition progresses
Structural Engineering advice sought on suitable design
Fixing method should not pose a hazard
Consider façade movements
Make regular checks on all fixings
Ensure demolition does not damage façade
Cut away built-in elements in a manner that does not weaken support
Support systems should not be damaged by removal of components

20. FALLS AND FALLING OF MATERIALS
Prevention of Persons from falling
Determine exclusion zones
Maintain safe place of work and safe access and egress
Scaffolds, stairs and catwalks should be maintained in safe condition
Use of independent work platforms or fall arrest at open edges

21. FALLS Prevention of falling objects on workers
Scaffolds should be sheeted with debris netting or reinforced plastic sheeting
Temporary structures e.g. tunnels, protective gantries, fans and crash decks
Maximum Load bearing of structures should also be of consideration

22. FURTHER CONTROLS Fire exit routes not obstructed at all times
Boarding up of windows
Use of appropriate PPE
Manual handling training and avoidance of excessive load
Restriction of access beneath demolition work at all times
Use of safe systems of work if building is occupied

23. DUST AND FUMES Dust and fumes Risk assessment for hazardous substances
Good housekeeping
Damping down
Designated vehicles route to and from site
Well maintained vehicle

24. DUST Contd. Suppress dust by use of water sprays
Use of air movers or LEV
Cover lorries and skips and apply speed restriction
Use of PPE
Lead/asbestos protection where necessary