DEMOLITION WORK

DCC 6242
BASIC BUILDING SERVICES

CHAPTER 6 : DEMOLITION WORKS

NAME : NUR EZZAH BINTI MOHD SIDIK
REG.NO : 04DKA18F2007

LECTURER : PUAN ROSNIZA BT AHMAD
CLASS : DKA5B

WHAT IS DEMOLITION WORKS ?

Demolition is the tearing-down of buildings and other N
structures. Demolition contrasts with deconstruction, which E
involves taking a building apart while carefully preserving T
valuable elements for re-use. UOLCECORPKROW
For small buildings, such as houses, that are only two or DS
three stories high, demolition is a rather simple process. The S
building is pulled down either manually or mechanically CO
using large hydraulic equipment. OR
SM
Demolition work involves many of the hazards EP
associated with construction. UR
However, demolition involves additional hazards VT
due to unknown factors which makes demolition IE
work particularly dangerous



THE OBJECTIVES DEMOLITION WORKS

 With the increased number of fatal accidents caused by demolition of high rise

buildings, safety in demolition works becomes a great concern to both the
government and the public. The reasons leading to such horrible accidents are
many, of which the lack of planning and supervision are the major ones.

Following the issuance of various practice notes to:
i. Authorized persons.
ii. Registered structural engineers.
iii. Registered contractors.
iv. Regarding the safety measures for demolition works for the protection of the public.
v. The building department has recently prepared a draft of the Code of Practice for
Demolition of Building

THE REASONS OF DEMOLITION WORKS

i. Commercials - to increase value of building when build new building.
ii. Aesthetic - renovate or build a new building to provide a more aesthetic

and ergonomic.

iii. Human health - to ensure the health and safety of building users.

iv. Human safety - not safe for building use.

v. Build new buildings.
vi. Renovation.
vii. Structure problems.
viii.Environment (near slopes) – the problem effect to the building and not

safe to using again.

ix. Population density - that area construction/building is not enough to

locate human density

x. Adjacent buildings – same like renovation and extension.

xi. Traffic - to solve the problem of traffic congestion



• Manual demolition includes any technique where hand tools such as

jackhammers, sledgehammers and picks are used

• Manual demolition has many of the hazards that are present in other major

demolition activities including unexpected collapse, falls, falling objects,
manual handling and exposure to noise, dust and hazardous chemicals.

• To manage the risk of unplanned collapses, the condition of roofs, walls and

floors of the building should be assessed by a competent person before
commencing demolition work.

• Where concrete members are being demolished manually, the reinforcement

shall not be cut while breaking of the concrete is in progress.

• Where pre and post-tension demolition work is undertaken competent person

advice should be sought as to demolition sequence. More information on the
demolition of pre and post- tensioned concrete.

• Areas where debris will fall should be barricaded off and signs erected to

prevent persons from entering before demolition starts.





• Mechanical demolition involves the use of powered mobile plant, such as
excavators, cranes, loaders and bulldozers. There may be a mix of hand and
mechanical demolition methods applied.

Crane and the Demolition Ball

Balling machines generally comprise a drag-line type crawler chassis
fitted with a lattice crane jib. The demolition ball, with a steel anti-spin
device, is suspended from the lifting rope and swung by the drag rope.
Balling should only be carried out by skilled operatives under the control
of experienced supervisors using well maintained machines adequate for
the proposed duty and standing on a firm, level base

Pneumatic Impact Tools

A pneumatic tool or air tool is a tool driven by a gas, usually compressed air supplied by a gas compressor. Pneumatic tools
can also be driven by compressed carbon dioxide (CO2) stored in small cylinders allowing for portability. Pneumatic tools
are commonly cheaper and safer to run and maintain than their electric power tool counterparts, as well as having a higher
power-to-weight ratio, allowing a smaller, lighter tool to accomplish the same task.

The example of pneumatic impact tools includes:

• Nail drivers.
• Demolition hammers.
• Chipping hammers.
• Riveting hammers.
• Air impact wrench.
• Jackhammer.
• Pneumatic angle grinder
• Pneumatic drill.

Pusher Mechanical arm

• The crusher attachment breaks the concrete and the reinforcement by the hydraulic thrust through the long boom

arm system. The hydraulic crusher can be operated from the ground outside the building. This method is also
suitable for dangerous buildings, silos and other industrial facilities.

• For environmental reason, it should be used wherever practicable because of its quietness

Explosive

• If explosives are to be used for demolition, the planning and execution, include preweakening, should be under

the control of a person competent in these techniques. For large demolition, the competent person is likely to be
an experienced explosive engineer; for smaller work, a shot-firer may be sufficient.

Safety Procedures and Best Practices of Demolition Works

• Top down methods are applicable for most sites, particularly for those situated in busy urban

areas. Other mechanical methods applied from the outside of the building may be suitable
for projects that have sufficient clear spaces.

LICENSE REQUIRED FOR ALL DEMOLITION WORKS

• A license is required to carry out certain types of demolition work. It is an offence to do any of the work

described as class 1, class 2 or class 3 demolition work unless licensed to do the work.

CLASS 1

 Work comprising the total demolition of a building or structure that is 10 metres or more in height when measured from the lowest ground level

of the building or structure to the highest part of the building or structure.

 Work comprising the partial demolition of a building or structure that is 10 metres or more in height when measured from the lowest ground

level of the building or structure to the highest part of the building or structure affecting the structural integrity of the building or structure.

 Work comprising the total or partial demolition of a building or structure; and involving the use of load shifting equipment on a suspended floor

CLASS 2
Work comprising the total or partial demolition of a building or structure that is less than 10 metres in height when measured
from the lowest ground level of the building or structure to the highest part of the building or structure but does not include :

 the total or partial demolition of a single storey dwelling
 Work of a kind referred to in paragraphs (c), (d), (e), (f), (g), or (h) of the definition of class 1.

CLASS 3

 Work comprising the removal of more than 200 m² of brittle or fragile roofing material from a building or structure



Conclusion

Demolition method applied in a structure depends upon various
factors such as site conditions, types of structure, age of building,
height of building and economy and most important its location with
presence of its surrounding with its structural stability. Controlled
demolition of building is necessary to ensure safety of both the
workers and the surroundings so as to cause least amount of injuries
and accidents.

Thank you !