Dempolition notes Part 3.pdf

Carry Out General Demolition of Minor Building Structures
© Australian National Training Authority 50
Carrying Out General
Demolition of Minor
Building Structures
CPCCCA3001
Course Notes

Dust
Demolition work can produce large amounts of dust,
some of which may be harmful to your health and
safety. Some dusts may be toxic, others may present
an explosive hazard, and some can be both toxic and
explosive.
The following methods may be used to suppress or
stop dust being generated, the method that you
choose will depend on the nature of the dust and the
type of hazard that it presents.
The method(s) that you choose to use should be
included in your work plan.
Match the description to the picture.
(i) water spray to wet the dust
(ii) hose down work area
(iii) vacuum
(iv) removal of waste and debris
before dust can accumulate
(v) dust collectors - extraction units
(vi) restricted or limited use of power tools

Noise
Noise is unwanted “sound”. Demolition sites can become very noisy due to the type of
work being undertaken, and the tools, equipment and machinery being used.
Noise can cause hearing loss by destroying the tiny hair cells (cilia) in your inner ear.
These hair cells may be destroyed depending on how loud the noise is, what frequency
(pitch) it is and how long you are exposed to it without protection.
Hearing loss is generally painless and occurs slowly over time, although instant hearing
loss can occur when exposed to very loud impact noise like that of a shotgun blast.
Noise can also cause a “ringing” sensation in the ears. Consider this to be a warning.
Noise levels are to be kept below a certain level, this is referred to as the “action level”,
above this level “action” is required to reduce the amount of noise being generated.
You need to be aware of what the law specifies the action level to be, in many states
it is 90dB (A), and 140dB (lin) is the peak level for impact noise.
Your work plan should specify how noise will be controlled and may include:
< Buy/hire quiet equipment/machinery.
< Isolate areas to prevent noise spreading.
< Safe work practices to reduce noise levels.
< Personal hearing protectors.
< Alter work hours.
< Redesign, equipment/machinery or job.
< Monitor the work area for noise levels.
< Train workers in hearing conservation.
< Carry out hearing (audiometric) tests.

Manual Handling
When undertaking manual demolition, that is when using hand held tools (eg. pick, sledge
hammer, jackhammer, etc), you are at risk of injuring yourself if you are not familiar with
safe manual handling techniques.
The term manual handling refers to each time you undertake an activity that requires you
to use force to lift, lower push, pull, carry or otherwise move, hold or restrain a person,
animal or thing.
Muscular sprains and strains are common injuries that can occur when people undertake
manual handling incorrectly. The back is the area of the body most commonly affected
(approximately 1 in 5 manual handling injuries result in back problems).
The following are some safe tips for correct manual handling:
< Think and plan what you are about to do and where you may need to go.
< Size up the load.
< Determine the best technique to use.
< Position your feet.
< Take a secure grip on the object being handled.
< Maintain a firm base of support.
< When lifting and carrying, pull the load in close to the body.
< Avoid twisting and lifting
< Avoid jerking or sudden movements.

< Use the correct muscles in your body for the job (don‟t make your back do all
the work, use your buttocks and leg muscles where possible).
Warm your muscles up before expecting them to work.
Try to keep your back in a balanced and stable
state (“S” Configuration).
< Vary heavy work with light work.
< Try to avoid repetitive movements.
< Allow certain muscles time to recover.
Use Teamwork
< Consider physical capabilities.
Your work plan should identify those jobs that require demolition to be done manually.
Where it is possible to avoid manual handling do so. Prevent the risk of injury by
redesigning the job or where possible by using mechanical assistance, eg. make use of
trolleys, cranes and forklifts.

Vibration
A common injury caused by continued exposure of the hands to high frequencies of
vibration from tools such as pneumatic hammers, concrete breakers, drills and chipping
hammers is referred to as “vibration white finger”.
Symptoms include the following.
Tingling and numbness in the fingers,
even after the machinery has been
switched off.
One fingertip temporarily turns white
and may start to ache.
The finger turns white with increasing
frequency.
Other fingers (though not usually the
thumb) begin turning white. After several
fingers turn white, the disease is
probably irreversible.
Increasingly frequent, painful attacks
occur at any time.
In extreme cases, the person may eventually lose their fingers. To avoid this injury:
use vibration insulators on tools and equipment
take regular breaks from using this type of equipment eg alternate with other kinds
of work
wear special gloves designed to insulate the hands from vibrations.
Personal Protective Equipment (PPE)
Depending on the nature of the hazard, personal protective equipment may be required
depending on the type of work being carried out, the nature of the hazard and the risk or
likelihood of being injured.
You should follow these four (4) general rules:
Rule 1: Select the correct equipment to protect against the hazard
This means that you need to be familiar with the hazards present prior to
carrying out demolition work and the capabilities of the personal protective
equipment that you select.

Rule 2: Fit the equipment correctly
We all come in different shapes and sizes, so too does personal protective
equipment.
It is referred to as “personal” protective equipment and
so it is important that your equipment fits you.
Rule 3: Maintain and service the equipment as required
The law actually requires some equipment be serviced on a regular basis and
within a specific period of time.
You don‟t want your equipment/machinery to let you down so you should be
familiar with what the law requires and how to keep your PPE in the best
condition.
WARNING
Remember: Once personal protective equipment
has been selected and correctly fitted
and you go to the trouble of looking
after it, where appropriate YOU MUST
USE IT!
Rule 4: Use personal protective equipment where it is required
You will be provided with the appropriate training to
ensure that you are competent to use the equipment.
Negative Fit Test Positive Fit Test
Place palms over cartridge
openings and inhale for 10
seconds. You should feel the
mask pull in toward your face
With palms over exhalation
valve opening exhale gently
into the mask. You should feel
pressure in the face piece.

Plant
Plant now includes the terms Tools and Equipment. Plant required for the demolition
process will vary depending on the task at hand. In general, a set of basic construction
hand tools can be used for small jobs like removing and salvaging windows. For large
jobs specialised plant is needed.
When undertaking demolition work it is important that you select and use the correct tools,
equipment and machinery designed for the job at hand.
Your work plan should specify the number and types of major items proposed to be used
to carry out the demolition work in accordance with the methods specified.
Some particular items of equipment or machinery may require persons to have a certificate
of competency (qualification/licence) before using/operating.
The tools, equipment and machinery required for the demolition may differ from job to job,
but will usually include some or all of the following:
(a) Basic Equipment and Tools
Wrecking or Nail Bar:
Used to lever materials apart and pull nails. It is available in a
range of sizes, with 600mm long being the norm. See Figure 1. It
is either made from hardened flat steel or forged hardened steel.
Another name for this tool is pinch bar.
Crow or spud bar
These are long straight steel bars used as a lever to lift/move
construction materials such as concrete paths, fence posts and heavy timber pieces. It is
also used to break up hard earth.
Sledge and lump hammers
Sledge hammers are heavy hammers used to break up masonry work. Common hammer
weights range from 2 kg to 12 kg. See Figure 2.
Figure 3: Sledge Hammer
A smaller version is called a lump (or club) hammer. It is used for light jobs and in
conjunction with another tool, such as a plugging chisel to remove the mortar around a
brick.
Rotary demolition hammers
These are used for breaking up masonry work,
small concrete paths and removing tiles. It
has interchangeable bits for different
applications. See Figure 3.
Figure 2: Wrecking Bar
Figure 4: Rotary Demolition
Hammer

Other hand plant
Other demolition hand plant include picks, shovels, wheelbarrows, brooms, water hoses
and spray attachments, pneumatic and electric tools, power leads, saw stools and planks,
ladders, power saws, hand saws, angle grinders, chisels, spanners, pliers, pincers and
hack saws.
For more information relating to the care and maintenance of these hand tools refer to
„Basic Building and Construction Skill’ 3rd
edition 2004, Chapter 8
(a) Machinery
< Lifting systems - hoists, cranes.
< Elevated work platforms.
< Concrete breaker.
< Earth moving equipment - bulldozer, front end loader, bobcat, excavator, trucks,
skid steer loader, traxacator loader.
WARNING All earth moving equipment should have a protective
cab to guard the operator against falling debris
during demolition.

The following rules apply to demolition tools, equipment and machinery:
Rule 1: Select the correct equipment for the job.
Rule 2: Understand how to use or operate the tools, equipment or machinery and
be aware of the requirements for certificates of competency.
Rule 3: Maintain and service tools, equipment and machinery as required.
These should be inspected for faults prior to use and immediately serviced or
repaired as appropriate.
If we all follow these rules we will reduce the risk of injury to:
< the public;
< site personnel;
< property; and
< the environment,
whilst enabling the demolition work to be done as efficiently as possible.

3. DEMOLITION OF A BUILDING/STRUCTURE
Your work plan must specify what methods of demolition are proposed to be used and
the proposed sequence to be followed when carrying out the work.
Sequence of Demolition
Generally, the sequence of demolition is usually the reverse order to which the
building/structure was constructed.
The following is the basic sequence of events that takes place once the site and structure
are investigated , the site is secured, services disconnected or bypassed and the work
plan developed and approved by the relevant authorities.
Please note, the sequence and methods used may differ from job to job depending on
each sites individual requirements.
Supervision by qualified personnel must be provided at each stage.
(a) Control Identified Hazards
Remove or otherwise control hazardous materials prior to stripping or demolition.
Protect openings in existing floors or walls and anywhere else where the risk of falling
exists.
(b) Stripping
Remove internal fittings, fixtures, services and anything
that is not load-bearing or will not affect the strength
or stability of the building. Some materials for salvage
and recycling may also be removed at this stage.

Plumbing fittings
A licensed plumber must isolate the plumbing
connections before demolition begins.
Undo fittings using plumbers' wrenches.
Undo mounting and securing brackets using
wrenches, screwdrivers and spanners.
Protect, label and store fittings for reuse.
Electrical fittings
A licensed electrician must isolate the electrical
connections before demolition begins.
Undo fittings using screwdrivers. Mounting
brackets aren't normally reused.
Protect, label and store fittings for reuse.
Benchtop cabinets
Look carefully to see how the item has been
installed and understand how the different parts
are joined together.
Remove any plumbing fittings.
Remove all doors, drawers, hinges.
Undo any internal screws or bolts that hold the
item together.
Remove any panels that come away.
Undo mounting or fixing brackets.
With most items, this should get you down to the
frame. Don't break up nailed or glued frames
unless absolutely necessary.
More time is spent cleaning up and repairing unnecessary damage.
You are better off being methodical and unscrewing cabinetry from
walls.
Figure 16: Kitchen cupboard
fixing points

Wall and floor tiles
Put down dust blankets so tiles falling from walls
fall on the blankets.
Chip tiles off using a bolster. Catch wall tiles as
they fall and stack them, or put them in a
wheelbarrow for disposal.
Clean up as you go with a dustpan or vacuum
cleaner.
Plasterboard
Remove all fittings (see above).
Put down dust blankets so pieces of plasterboard
falling from walls fall on the blankets.
Remove plasterboard with a crowbar or claw
hammer, with as little force and breakage as
possible.
Clean up as you go with a dustpan or vacuum
cleaner.

Remove windows and doors Remove any windows and doors from
the frame. It is quite possible that these can be recycled.
Windows set in brickwork
Tape the window glass with crosses, so that if it breaks it
stays together.
Make sure that anything supported by the brickwork or
timber frame (like roof beams) is supported some other way
before demolition begins. For example:
o remove three or four bricks above the window, to
make equally spaced holes in a line, just above the
window opening
o put strong timber beams about 2 m long through the
holes
o support the timbers at both ends with adjustable
props, screwed up so that the timber beams take all
the load of whatever is above the window.
Remove small amounts of brickwork around the window
frame using a bolster and hammer. Work from the inside if
possible, so rubble falls outside.
Carefully remove the window, trying not to break the glass.
Use a crowbar to pull apart nailed timber.
Be careful with nails sticking out. If timber is to be reused or
stored, remove all nails.
Roof coverings
Make sure scaffolding is in place around the edge of the roof
or a fall protection system in place..
Lash a ladder in place to the roof.
Set up a chute or similar enclosure to take the tiles to
ground level without dropping them.
Pass removed sheets to other workers to prevent the sheets from falling. After
all the roof sheets are removed the battens and fascia can be removed.
Always check that the area below is clear before lowering material to the
ground.
General roof safety information
There are many more recommended work practices that should be adopted for
the safety of all roof workers. To find out about these you should contact the
local WorkCover or Work Safe office and ask for a Code Of Practice relating
to safe work on roofs and demolition. Alternatively, visit a website and down
load a copy.
ACT - http://www.workcover.act.gov.au/
Remove rafters
Now work from the inside of the structure. Do not work from ladders leaning
against side walls. Set up a platform using trestles and two planks. Pry the
rafters loose from the top plates. Flatten or remove protruding nails to prevent

injury.
Timber frames (eg to remove an internal wall)
Support the top of the frame (and any load on top of it, like
roof beams) with adjustable props before starting to
demolish the frames.
Remove the noggings from the frame, then the uprights.
Replace the timber support cross beams with single
adjustable props at every load bearing point.

Demolition of walls
Whether you are taking out a complete building, removing an internal wall, or making a hole in a wall for a
new door or window, you will need to consider if the wall is load bearing or non load bearing.
During the planning process these points should have been established. All external walls are load bearing
and depending on the roof structure and structural design some internal walls may be load bearing as well.
You will need to inspect the roof space and determine the roof structure and direction of ceiling joists or
roof truss placement. If it is a truss-roof construction the internal walls should not be load bearing.
If the roof is pitched construction you will need to note the walls that support the ceiling joists as these are
load bearing walls. Walls that support any roof member are load bearing. Before a load-bearing wall is
demolished or altered, to make way for an opening, then the roof structure will need temporary support.
Adjustable metal props are used to provide this support. See Figure 10.
Propping
Check that the condition and serviceability of the props before use.
Check the Safe Working Load (SWL) of the props for the intended load.
Do not exceed the manufacturer's SWL.
Props need to be placed so they provide structural support. This is
achieved by placing props so that roof loads are transferred onto piers.
Where this cannot be achieved a sole plate that spans across floor
joists is required to distribute the load. See Figure 11. Never place
sole plates parallel to floor joists as the prop load will punch through the
timber floor. It may be useful to use some form of protective packing
between the timbers and finished floors and ceiling to reduce
unnecessary damage. A strip of carpet is useful. See Figure 12.
Make sure you leave enough space between the props and the wall so
you can adjust the props. Keep props vertical and fastened to the
timber supports to prevent accidental dislodgment. To maintain
stability, place diagonal bracing between the props.
Figure 10:
Adjustable steel
prop
Figure 11: Located
prop
Figure 12: Propping a
ceiling

Timber framed walls
To make an opening in a load bearing timber framed wall you need to determine the size of the lintel or
head required to support the opening. You will need to consult AS 1684 –1999 – Residential timber-framed
construction Parts 2/3, for details and tables for recommended sizes or consult an architect or engineer.
Before demolishing, make sure that the roof has been sufficiently propped. Check the position of any
services that may be in the cavity. This can be done from adjoining rooms, from under the floor and
from the roof space. Calculate the size for new opening. Remove the plasterboard from floor to
ceiling and well past the side of the opening. Often it is better to replace the plasterboard to the whole
wall. Use a utility knife and straight edge to score the plasterboard so you don’t destroy the surface of
the remaining plasterboard
when you remove the unwanted section. Use a hand saw to cut the outline of the opening taking care not
to cut through electrical wires or plumbing. Never use a power saw as you will cause a lot of damage very
quickly. If you hit electrical wires you will be electrocuted. If you hit a water pipe you will have water
spurting into the room and causing damage. If you hit a metal brace you will damage the saw blade.
Figure 13: Cutting out timber components
Make 450 angled cuts across noggins and studs to aid removal. See Figure 13. Remove any noggings,
studs and plates that are not needed and de-nail the frame members. Set out the new studs, noggings,
jack studs and lintels as you would for a normal frame.

Masonry walls
A falling brick can cause death or serious injury. When
putting in an opening into an existing brick wall the bricks
immediately above the opening can fall. See Figure 14.
If the opening is less than 900mm, and the brickwork is solid,
then the opening should be self supporting. If the
brick bonds are poor then the brick work will collapse in a
triangular pattern as shown in Figure 14. If this happens
insert the lintel or arch bar and re- bricking the area
above the opening head.
If the brick opening is greater than 900mm a needle will
be required to support the brickwork above the opening.
See Figure 15. When the opening is greater than
1800mm, two needles are needed.
Bricks can be removed using a lump or club hammer, and plugging chisel. If the mortar is crumbly, a
hacksaw blade or old saw blade may be adequate.
Rem
embe
r if
you
are
maki
ng an
openi
ng for
a
door
or
windo
w in
an
exter
nal
wall in full masonry or brick veneer construction allow for insertion of flashings to frames and masonry.
Allow for the insertion of lintels. Openings larger than 1200mm wide will require an angled lintel.
Brick walls should be demolished course by course. The work should be done from safe working platforms
like a scaffold or elevating work platform and NOT from a ladder. Do not stand on top of a wall being
demolished. Isolate the area where debris will fall. Use barricades and signs to keep people away from
the area. Brace adjoining walls if by removing one wall the remaining walls become unstable.
Figure 15: needle(s) through brick construction
Figure 14: Brickwork
opening

Concrete floors
Remove all floor coverings.
Cut an outline of the area to be broken up with a diamond-tipped electric saw.
Break out the concrete to be removed with a pneumatic chisel.
Remove all rubble as you go.
(e) Remove demolished materials
The demolished materials should be removed progressively from the site and should
not be allowed to accumulate to the extent that it presents a hazard to the site
personnel or the public.
Materials should not be thrown down, but enclosed chutes or similar should be used
where possible.
You should always take care to avoid leaving parts of the building in a dangerous
state when operations cease for the day, no material should be left unsupported or
hanging dangerously.
Clean up and waste disposal should be done throughout the
demolition process. Pick up any rubbish, like paper, timber offcuts,
old nails or used packing tape. Put in the waste bin.
For general house renovation projects sizes from 2m3 to 6m3 are common.
See Figure 8. For large projects bin sizes up to 22m3 are available. When
the site size or access restricts the size of bin you can use, smaller bins can
be removed and replaced on a regular basis. Some bins have drop down
sides or gates to allow wheel barrow access.
After each stage of the demolition process, put away tools that are
not being used. Tools are expensive and usually made to last. They
shouldn't be left lying around. Pick up all the tools and clean them if
necessary. Put any tools (like spanners) away in their holders. Store
tools in a clean, dry place.

Methods of Demolition
Demolition work is difficult and skilled. It requires knowledge of the methods and materials
of construction of the structure being demolished.
Demolition proceeds at a rapid pace and workers must constantly appraise the strength,
stability and weak points of partly demolished structures.
When selecting a method of demolition, they must consider:
< how and in which direction things will fall; and
< whether the collapse of one wall or arch will cause adjacent walls to collapse.
Methods and techniques used for demolition will vary from job to job.
The following are three (3) methods commonly used:
(i) Manual demolition
This utilises techniques that involve the use of hand held tools.
You are permitted to work only from a safe and serviceable working platform.
You are not to work from the top of a wall or partition being demolished or an open edge
unless attached to an approved fall arrest system. See personal protective equipment.

(ii) Mechanical demolition
Utilises techniques that require the direct use of mechanical plant, such as:
< Demolition by crane (demolition ball)
Legal requirements specify that the crane shall be of an approved type and can only
operate within a specialised area under certain conditions.
The crane operator must possess the appropriate crane operator‟s licence or
“Certificate of Competency”.
< Demolition by tractor mounted equipment
Tractor mounted equipment should only be operated from firm, level ground to
minimise the risk of tilting.

(c) Earth moving equipment
Earth moving equipment may be used on ground level and only above ground level if it
can be shown that the floor is capable of sustaining the load of the equipment plus the
demolished materials.
(d) Collapse Induced by Explosives
This method utilises explosives to collapse a building or structure, special conditions apply.
The Regulatory Authority must approve the use of explosives prior to the work being
carried out.
Watch Canberra Hospital Video

4. TECHNIQUES
Manual and mechanical methods of demolition may utilise the following techniques:
< Felling by pulling with ropes or chains
< Felling by direct pushing or pulling.
The following list includes buildings and structures that may require special techniques to
be used and should not be demolished without consultation and direction from a suitably
qualified or competent person(s) familiar with the type of building or structure to be
demolished.
< Multi-storey buildings

< Industrial processing plants - tanks for flammable and combustible liquids.
< Specialised roofs and flooring systems
pitched roofs
domed, vaulted, or arched roofs
flat roofs (generally demolished as for floors)
steel framed floor systems
composite steel-and-concrete floors

< Concrete-framed floor systems
slabs supported only by beams or walls;
slab panels supported by beams and columns;
slabs without beams supported by columns (flat slabs); and
ribbed slabs.
Figure 5 CONCRETE - FRAMED FLOOR SYSTEMS
beams in beam-and-slab construction;
pre-stressed slabs and beams;
columns and walls;
 Masonry walls; and
 Concrete walls.
Basement and other below-ground structures;
Independent towers, masts and chimneys; and
Damaged buildings or ruins.

WARNING
Remember: Unless otherwise permitted by the
Regulatory Authority, demolished
materials are not allowed to fall freely
outside the structure unless confined
within a chute or similar enclosure, and
shall not be allowed to fall freely within a
structure unless confined within a shaft,
or similar enclosure.
WARNING
Remember: In multi-storey buildings where materials
are allowed to fall freely through internal
floor openings, there are special
conditions that apply, these involve the
use of guarding, barriers, enclosures and
restricted access.
5. CLEAN UP AND WASTE DISPOSAL
It is very important that good housekeeping, clean-up and waste disposal procedures are
carried out on an ongoing basis on a demolition site in order to look after everyone‟s health
and safety whilst at work.
The following tips may help you to maintain a safe work environment:
a) Waste, rubble and debris should be removed as it is created.
b) Recyclable materials should be stored separately from waste
materials.
c) Safe work practices should be used when handling hazardous
materials. These should be disposed of at an approved hazardous
waste site. Personal protective equipment that is contaminated by
hazardous materials should be disposed of in the same way.

Dispose of Hazardous Waste Properly
(d) Any personal protective equipment contaminated with hazardous materials must be
disposed of as hazardous waste.
(e) Storage areas should be accessible at all times and kept neat and tidy.
(f) If materials are stock piled on site, keep neat and tidy and avoid dust generation
using dust suppression techniques.
(g) Keep all points of entry (access ways) and exits clear at all times. This also applies
to: passageways, aisles, doorways, roadways, and any areas where people or
machinery may need to be present.
(h) Materials/debris and rubble that may collect around the equipment and machinery
should be cleared away regularly, particularly if the materials are hazardous.
(i) Don‟t leave unwanted tools or equipment lying about, put them away in their rightful
place.
(j) Tools, equipment and machinery should be kept clean and in a workable condition.

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