C3001 / UNIT 4 / 1
: To understand demolition works in a safe and
Specific Objectives :
At the end of this unit you should be able to:
understand demolition processes.
explain demolition methods.
describe safety precautions taken in demolition of building.
recognize machineries used in demolition.
C3001 / UNIT 4 / 2
DO YOU KNOW?
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 Authorized Persons,
Registered Structural Engineers and Contractors, regarding the safety measures for
demolition works for the protection of the Public, the Building Department has recently
prepared a draft of the Code of Practice for Demolition of Building.
C3001 / UNIT 4 / 3
It is intended to be followed by specialist demolition contractors for the
demolition of various building works in Malaysia, aiming at minimizing the risks of
injury to persons and damage to properties, the risks of endangering the health and safety
of site personnel and damage to the environment in the vicinity.
The Code sets out the guidelines for demolition of the buildings from roof level to
ground level and the demolition of basement, underground tanks, as well ascertain
common civil engineering structures, but not major civil engineering works such as
underpinning, excavation, highway bridges, dams and nuclear reactors.
General guidelines are also given for the design of temporary works and checking of
temporary structures. The code covers common methods typically used in the demolition
of buildings in Malaysia, but exhaustive guidelines for all methods are not given. The
code does not intend to discourage any other demolition methods, which may be used
subject to approval. The content of the unit includes the following topics:
Machinery used in demolition
Based on the Oxford Fajar dictionary demolition
means to “ pull to or knock down a building ”,
and another meaning for demolition is a “ highly
skilled and dangerous activity in terms of
damage to life and property”.
Rina , what is the meaning
of “Demolition” ?
Demolition Tariffs And Reasons For Demolition
C3001 / UNIT 4 / 4
C3001 / UNIT 4 / 5
Does anybody know the causes of
Causes Of Demolition
It’s ok, let me tell you about the causes
of demolition, the example are:
Building new buildings
Environment ( near slopes )
C3001 / UNIT 4 / 6
Let us list together the
1. Before demolition
a. identify site locations, special site restrictions and impact of special
b. identify buildings/structures to be demolished
c. verify dimensions of site and building
d. identify hoardings requirements
e. verify building construction, types of materials
f. verify existing fixtures
g. verify the building use
h. verify utilities location
i. prepare demolition schedule
j. test and remove hazardous materials
C3001 / UNIT 4 / 7
k. identify the safety measures for protection of the public
l. arrange for debris handling
m. prepare demolition plan
n. prepare stability report with calculations
o. apply consent (also submit supervision plan, names and details of
Technically Competent Persons.
2. During demolition
a. install site precautionary measures
b. remove hazardous materials
c. inform site personnel the specifics and precautionary measures
d. establish emergency access
e. establish line of communication to supervisor
f. progress work in accordance with method statements approved.
g. remove debris to avoid accumulation
h. control dust emission
i. adequate supervision
j. protect party walls
k. ensure workers follow safety procedures
l. ensure machines and equipment are well maintained.
m. provide security
n. schedule regular inspection and maintenance of scaffolding.
C3001 / UNIT 4 / 8
3. After demolition
a. clear debris and level site
b. secure boundaries
c. protect all excavations
d. for sloping site and/or site with retaining wall
i. seal ground surface
ii. provide surface drainage
iii. provide demolition plan to the foundation contractor for
maintaining the supports.
Let’s answer the questions
in the next activity to test
C3001 / UNIT 4 / 9
State whether the following questions are True
Commercials, aesthetic, human
health, human safety, build new
building are the example of the causes
Demolition processes have 3
situations; it is before, during and
Demolition means to “ pull to or
knock down a building ”, and another
meaning for demolition is a “ highly
skilled and dangerous activity in terms
of damage to life and property”.
C3001 / UNIT 4 / 11
Types And Ways Of Demolition
In many circumstances, buildings and structures should be demolished in the
reverse order to their erection; although where partial demolition is involved a more
careful evaluation of the nature of the effects of the demolition is necessary.
Normally, the demolition contractor is able to adopt a method of work which:-
C3001 / UNIT 4 / 12
gradually reduces the height of the building; or arranges the deliberate controlled
collapse of the building or structure so that work can be completed at ground
The choice of demolition technique will depend on the nature of the building or
structure and its environment. Risks to the public, operatives involved in the demolition
process and adjacent structures and buildings should be considered.
Demolition techniques may be categorized as:•
Piecemeal demolition, using hand-held tools or machines, to reduce the height of
the building or structure gradually;
Deliberate controlled collapse, demolition to be completed at ground level.
Demolition of buildings or structure by hand-held tools such as electric or
pneumatic breakers, sometimes as a preliminary to using other methods, should be
carried out, where practicable, in the reverse order to the original construction sequence.
Lifting appliances may be necessary to hold larger structural members during cutting and
for lowering severed structural members and other debris. Chutes may be used to
C3001 / UNIT 4 / 13
discharge debris into a vehicle or hopper. Foundations would normally be grubbed up by
Figure 4.1 demolition by hand
4.2.2 Machinery’s Components
Simple roof structures supported on wall plates should normally be demolished to
the level of wall plates by hand, but if this may involve unsafe working, then demolition
totally by machine may be appropriate.
C3001 / UNIT 4 / 14
Where a building that is to be demolished by machine is attached to another
structure, the two properties should be separated by the use of hand methods before the
main demolition process begins.
When any part of a building is being demolished by a balling machine, pusher
arm or similar equipment, only the machine operator and banks man should be allowed
close to the working area. The cabs of all machines should be strong enough to protect
the operator against the fall of debris. In particular, the windscreen and roof light should
be of shatterproof material and guarded by a grille of steel bars or a substantial mesh.
Demolition by machinery’s components
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.
C3001 / UNIT 4 / 15
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.
The manufacturer should be consulted before a machine is used for balling to
establish any restrictions on the type or length of jib or the weight of the ball.
Balling operations subject cranes to dynamic stresses and wear, and the ball
chosen should have the minimum weight necessary for effective use. In many cases,
demolition balls of quite light weight will be adequate.
Floors should be demolished by dropping the ball on the highest remaining floor
and allowing the debris to fall inside the building. The debris should be removed
regularly to prevent excessive weight accumulating on the lower floors.
Walls or columns can be demolished either by swinging the ball in line with the
stationary jib, using the drag rope, or by slewing the jib. The ball should not swing by
derricking the jib.
C3001 / UNIT 4 / 16
C3001 / UNIT 4 / 18
Hydraulic pusher arm
Articulated, hydraulically-powered pusher-arm machines are normally mounted
on a tracked or wheeled chassis, and have a toothed plate or hook for applying for
applying a horizontal force to a wall. The machine should stand on a firm level base and
apply force by a controlled movement of the pusher arm.
Mini Hydraulic Breaker
Hydraulic Mobile crane
( 20 T - 200 T )
C3001 / UNIT 4 / 19
Long arm excavator
Long Arm Excavator
Long Arm Excavator
C3001 / UNIT 4 / 20
If explosives are to be used for demolition, the planning and execution, include
pre-weakening, 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.
When the use of explosives is contemplated, it is usual to employ a technique that
will ensure the total demolition of the whole building by staging a controlled collapse.
The explosive charges are set and fired in a sequence that will weaken the structure in
such a way that the building collapses in upon itself.
Although we tend to think of explosives as devices producing spectacular bomblike explosions, the use of non-explosive "explosives" is now at an advanced stage. These
non-explosive techniques are essentially expanding charges that achieve the same results
as explosives but without the noise and initial devastating blast.
“Did you understand all the information in this
unit? If you have difficulties go through the notes
again. Now let us answer the question in the next
C3001 / UNIT 4 / 21
Complete the sentences below by providing the
Demolition techniques may be categorized
Manual and Machinery components are
List the machinery’s components. Write
your answers in the space below.
Who should be allowed close to the
C3001 / UNIT 4 / 22
Based on the Oxford Fajar dictionary Demolition means
to “pull or knock down a building”, and another meaning
for demolition is a “highly skilled and dangerous activity
in terms of damage to life and property”.
Demolition techniques may be categorized as:Piecemeal demolition, using hand-held tools or machines,
to reduce the height of the building or structure gradually;
Deliberate controlled collapse,
completed at ground level.
3. Manual and machinery components are ways of
4. a) balling machine
b) hydraulic pusher arm
long arm excavator
The machine operator and banks man should be
allowed closed to the working area
C3001 / UNIT 4 / 23
C3001 / UNIT 4 / 24
Answer the following questions:
Give FIVE of the most important safety precautions which must be
taken into account before starting a demolition project to prevent your
actions from undermining the structural integrity of the building?
Give THREE proper attire and tools needed to ensure a safe
environment in a demolition project?
Give FIVE steps that need to be taken to ensure the homeowner’s
Explain how to schedule the best time to start a demolition project.
List three examples of Machinery’s Components.
C3001 / UNIT 4 / 25
ANSWER NO. 1
Always know exactly what it is you're about to remove. Before you move or
remove anything, always check to see what's behind it, below it and what it might
Never assume that a structural member you're about to remove doesn't support
When removing framing that is near electrical wiring, shut off the electricity, even
if you're not removing the wiring. Do the same for any plumbing or gas lines. A
single nick with a saw blade or a drill can cause disastrous results.
When removing electrical wiring, turn off the circuit breaker or remove the fuse
controlling the circuit you're working on, and then post a note on the electrical
panel warning others not to turn it back on.
Never attempt to work on a gas or water line without first making certain it has
been shut off. Also, do not assume that a shutoff valve works - after closing the
valve, test the line to be absolutely sure it's off.
C3001 / UNIT 4 / 26
ANSWER NO. 2
Use only the proper tool that is designed for a particular task - don't improvise. If
you are prying up a board, use a heavy pry, not a big screwdriver. On the other
hand, use a screwdriver to remove a screw; don't yank it out with a pry bar.
If you don't have the proper tool for the job, don't proceed until you are able to
buy or rent one. If you need a jack to lift a heavy beam, get one - don't try to rig
up a couple of 2 X 4 as a lever. If scaffolding is required to work safely at a given
height, get some and take the time to set it up correctly - balancing a 2 X 12 on a
couple of ladders is an invitation for disaster.
Wear the appropriate clothings. Demolition work requires long pants, a heavy
shirt, and solid shoes - allowing your crew to work in shorts and tennis hoes can
net you a serious fine. Wear gloves, and always wear eye protection. If anyone is
working above you, or if there is any potential for falling objects, make hard hats
C3001 / UNIT 4 / 27
ANSWER NO. 3
Secure all tools at lunchtime, at the end of the day, and during absence from the
job site, cords need to be unplugged and sharp tools placed in a safe and secure
enclosure. Remember that children are fascinated with construction sites, and this
curiosity can lead to serious injuries.
Motorized equipment needs to be securely locked and the keys placed in a safe
Take down ladders at the end of the day. This includes covering holes in the floor
and placing temporary barricades over window and door openings.
If you cannot cover or otherwise close off an area - such as an open trench that is
still in use - ring the area with caution tape and place lighted barricades at regular
intervals as a warning.
Cover holes and other danger spots.
C3001 / UNIT 4 / 28
ANSWER NO. 4
In most cases, demolition work is best left until the last possible moment in order
to help avoid weather and security problems. The addition should be completely
framed, roofed, and enclosed with siding, and exterior windows and doors should
be installed, before the walls connecting the addition with the existing house
should be removed.
Try to work in stages as much as possible, again doing only as much
demolition work as necessary for a particular phase of the construction. You may,
for example, need to remove a small section of siding at the base of the wall in
order to align the new foundation with the old one, or perhaps take down some
drywall to line up the new ceiling joints.
Even if it's all coming down eventually, it's best to remove only what you
need to accomplish the task you are working on at the moment.
ANSWER NO. 5
Long arm excavator
Hydraulic pusher arm