1
TOPICS COVERED
- INTRODUCTION TO SCAFFOLDING
- TYPES OF SCAFFOLDS
- MATERIAL FAMILIRISATION
- TOOLS REQUIRED
- SAFETY WHILE WORKING
- TERMINOLOGIES
- LIGHT DUTY ACCESS TOWERS
- PRACTICALS
WHAT IS SCAFFOLD?
Scaffold is a temporary structure that
provides access, or from which
persons work, or that is used to
support materials, plant or
equipment.
Relevant Standard: BS 5973-1993
BS EN 12811-1(Temporary Work Equipment. Part 1
Scaffolds – Performance Requirements and General Design)
2
Where work cannot be safely done from
the ground or from part of a building or
other permanent structure there shall be
provided either scaffolding or where
appropriate ladders or other means of
support, all of which shall be sufficient
and suitable for the purpose. And where
reasonably practicable, be suitable and
sufficient to provide safe access to and
egress from every working place.
Scaffold shall be erected by trained
scaffolders or other competent
persons possessing adequate
experience of such work.
All material for any scaffold shall be inspected
before use , by a competent person. Materials used
shall be of suitable quality and good condition, and
they shall be free from patent defect likely affect
their strength materially. Items not meeting the
standard to be discarded.
3
SCAFFOLDING
COMPONENTS
SCAFFOLD TUBES
Tubes should be manufactured and tested in
accordance with BS 1139 Part 1
‘Specification for tubes for use in
scaffolding’
Three main types of tube are in common use
through the scaffold construction:
Black steel tubes
Galvanized steel tubes
Aluminum alloy tubes
4
Scaffold tubes cont.
Both black steel and galvanized steel
tubes possess the same properties,
except galvanized tubes are more
resistant to corrosion. These common
properties are:
• Outside diameter 48.3 mm
• Nominal wall thickness 4.0 mm
• Weight, approx 4.5 kg/m
TUBES
ACCORDING
TO BS 1139-1
GALVANISED
DIA – 48.3 mm
WALL – 4.0 mm
LENGTH – 6.3 m
WT – 4.5 kg/m
5
Tubes cont. Aluminum tube
Aluminum tube has the same diameter as steel,
but is slightly thicker and much lighter. It is
more flexible than steel and not as strong.
• Outside diameter 48.3 mm
• Nominal wall thickness 4.47 mm
• Weight 1.67 kg/m
Aluminum tube is tempered using heat during
manufacture. Any further heat applied to the
tube may weaken it.
Repair of Tubes
Corroded tubes should be cleaned with a
wire brush and the extent of damage
assessed by a competent and experienced
examiner. Bent steel tubes may be
straightened using a rolling machine, but
bent aluminum tube should be thrown
out. Repairing scaffold tubes is a skilled
job and must only be undertaken by
specialists.
6
Tubes cont. Inspection
The ability of a scaffold to carry it’s load is
largely dependent on the strength and
condition of the of the tubes used in
construction. Consequently, tubes must be
checked to ensure they are:
Straight
Free from cracks, splits, bad dents and
excessive corrosion
Cut square and clean each end
TUBES Storage
Scaffold tubes are generally supplied in
lengths of 6.3 m. Shorter tubes are
available from stock; for example,
transoms of 1.5 m and 1.8 m length.
Whenever possible tubes should be sorted
according to length and stored in racks with
Their ends flush. This make it easier to
identify and select tubes of the required
length.
7
TUBES
DAMAGES THAT CAN HAPPEN
TO TUBE DUE TO MISUSE
BOARDS
WHITE WOOD
ACCORDING TO
BS 2482
WIDTH – 225 mm
THICK – 38 mm
LENGTH – 3.9 m
8
BOARDS
MAXIMUM BOARD LENGTH – 3.9 m
SHORTER BOARDS ARE ALSO
AVAILABLE.
BOARDS CAN BE CUT USING A
HAND SAWACCORDING TO
SPECIFIC SITE REQUIREMENTS
BOARDS
OTHER BOARDS AVIALBLE
50 mm THICK x 225 mm WIDE
63 mm THICK x 225 mm WIDE
25 mm THICK x 150 mm WIDE FOR
TOE BOARDS
9
BOARDS
DAMAGES THAT CAN HAPPEN
TO BOARDS
BASE PLATE
BASE PLATE
STEEL
WIDTH – 150 mm
LENGTH – 150 mm
THICK – 4 mm
10
BASE PLATE
ALL VERTICAL
MEMBERS
SHOULD
HAVE A BASE
PLATE.
BASE PLATE
SPREADS
THE LOAD TO A
LARGER AREA
COUPLERS / FITTINGS
TO CONNECT / JOINT PIPES
TO FIX BOARDS
TO FIX LADDER
11
RIGHT ANGLE COUPLER
(DOUBLE COUPLER)
A COUPLER USED TO JOIN TUBES AT
RIGHT ANGLES TO EACH OTHER
BS 5973 (1993)
Ref BS 1139 Part 2
(1993)
Minimum SWL (SLIP
ALONG TUBE) – 6.3
kN (635 kg)
SWIVEL COUPLER
A COUPLER USED TO JOINING TUBES AT
VERYING ANGLES OTHER THAN RIGHT
ANGLE
SWL (SLIP ALONG TUBE) – 5.3 kN (535 kg)
12
GIRDER COUPLER
(BEAM CLAMP)
FOR CONNECTING SCAFFOLD TUBES TO
RSJs. UNITS MUST BE USED IN PAIRS.
LOADING REFER TO MANUFACTURER’S
RECOMMENDATIONS. NORMALLY USED FOR
SLUNG SCAFFOLDS.
PUTLOG COUPLER
(SINGLE COUPLER)
A coupler used for fixing a putlog or
transom to a ledger.
BS 5973 (1993)
Ref BS 1139 PART 2
(1991)
Minimum slip resistance 1.2 kN
SWL 0.53 kN
13
BOARD CLIPS
A clip for fixing toe board
to a scaffold tube
BOARD CLIPS
A clip for fixing a platform
board to a scaffold tube
14
SLEEVE COUPLER
An external coupler
used to join tubes in
length.
Standards not in the same
level.
Ledgers not in the same bay.
Minimum(Tensional)
(Class A) SWL 1.5 kN
(Class B) SWL 3.0 kN
JOINT PIN
An expanding fitting placed in
the bore of a tube to connect
one tube to another coaxially.
Has no slip resistance
15
LADDER CLAMP
Used to fix ladder to a pipe
LADDERS
Access to the scaffold
Commonly Aluminum
6.0 m and shorter
75 Degree, 4:1 ratio
1 m above platform
Adequately supported
16
GIN WHEEL
Used for raising and lowering components
and materials to a scaffold structure.
SWL stamped on the frame.
18 mm dia. rope to used
CASTOR WHEEL
Used for making mobile scaffolds
Should be erected on hard level ground
only, Ex: concrete ground.
SWL identified on frame of wheel
17
DIFFERENT TYPES
OF SCAFFOLDS
18
Freestanding scaffold
Free standing structures which are
self-supporting and do not depend
totally on other structures for their
rigidity or stability. Three classes of
these structures are generally
recognized:
Free standing scaffold cont.
1. Light Duty Access Towers
Stationary and mobile for use inside buildings
(Imposed load not greater than 1.5 kN/m2)
2. Light Duty Access Towers
Stationary and mobile for in the open
(Imposed load not greater than 1.5 kN/m2)
3. Heavy Duty Towers
These are always built to design details.
19
TOWERS
FREE STANDING TOWERS
Ground should be level and suitable to erect
the scaffold.
Maximum bay length – 2.7 m
Min. Width – 1.2 m
STABILITY
Max height (outside) (inside)
Mobile – 3xW 3.5 x W
Stationary – 3.5 x W 4xW
20
FREE STANDING TOWERS
Bracing – On all sides on all lifts.
Plan brace on every alternate lift
starting at base lift
FREE STANDING TOWERS
Always try to lower or hoist
materials in side the tower to avoid
any overturning of the structure
21
FREE STANDING TOWERS
Access – by ladder on
small side in side tower
Should extend 1.0 m
above platform
Adequately tied
Mobile Towers Only.
Joints in standards should only be made
with sleeve or parallel couplers.
Wheels or castors not less than 125 mm
in diameter and fitted with brakes
which cannot be released accidentally,
should be locked into the base of the
standards. The safe working load
should be marked on the castor wheel.
22
Independent Tied
Scaffolds
A scaffold, which has two lines of
standards one line supporting the
outside of deck and one the inside.
INDEPENDENT TIED
23
Putlog Scaffold
A scaffold which has one line of
standards to support the outside
edge of the deck and utilizes the
wall being built or the; building to
support the inside edges
PUTLOG SCAFFOLD
24
Slung scaffold
A scaffold hanging on tubes,
ropes or chains from a structure
overhead. It is not capable of
being moved or lowered
HANGING (SLUNG)
25
BIRD CAGE
CANTILEVER
26
TOOLS
Box Spanner
Normal size – 21 mm
Spirit Level
With magnetic base
Hammer
Tape measure
SAFETY
27
SAFETY GEAR
Full Body Safety
Harness with
double lanyard
A tool pouch is
recommended to
avoid any dropped
objects
SAFETY GEAR
All other PPE is required as well
Overalls
Helmets
Safety Glass
Safety Shoes
Gloves
Any other site specific if required
28
SAFETY AT WORK
Use full body safety harness with double
lanyard properly. Anchor in a suitable
place above shoulder level as far as
possible.
Most of the accidents happen while
moving from one place to other. Never
remove both lanyards from the anchoring
point simultaneously.
SAFETY AT WORK
Never through couplers, fittings &
materials. Always lift or lower using
suitable material bag, rope and gin wheel if
required.
Secure all tools to avoid any dropped
objects
29
SAFETY AT WORK
Use minimum three boards for temporary
platforms with correct spacing of transoms.
Temporary boards should be secured
properly.
Use the aid of near by structure or other
person to stand up long tubes and ladders.
SAFETY AT WORK
Install scafftag with “Do Not Use Scaffold”
during erection, modification and dismantling
to warn others
Inform scaffold inspector to
carry out inspection after erection
is complete.
30
SAFETY AT WORK
Proper manual handling techniques should
be used to avoid any back injuries
WRONG CORRECT
TERMINOLOGY
31
SOLE BOARD
To spread the load
Commonly two up rights on one board
Minimum 610 mm if single up right
STANDARD
Vertical up right tube
members.
Takes all the load
Should have base plate
Should be level
32
LEDGER
Horizontal tubes running parallel to
the wall
TRANSOM
A tube spanning across ledgers to
form the support for boards or units
forming the working platform or to
connect the outer standards to the
inner standards.
33
TRANSOMS
Holds both rows of standards
Supports scaffold boards (1.5 m / 1.2 m)
Overhang from end transom – 2” to 6”
BRACE
A tube placed diagonally
with respect to the
vertical or horizontal
members of a scaffold
and fixed to them to
afford stability
34
FACADE BRACE
A tube fixed to the face of the scaffold
to avoid swaying. Also called sway brace
PLAN BRACE
A brace in a horizontal plane, normally
on tower scaffolds on corner to corner
standards
35
LIFT
The assembly of ledgers and transoms
forming each horizontal level of a
scaffold.
LIFT HEIGHT
The vertical distance between two lifts
measured center to center. 2.0 m
KICKER LIFT
FOOT TIE
Lift erected near to the ground.
Approx 150 mm from ground
36
BASE LIFT
First Lift from the
Ground
Max. 2.7 m, other
consecutive lifts
Max. 2.0 m
BAY
The space between the central lines of
two adjacent standards along the face of
a scaffold.
37
BAY LENGTH
The distance between the
centers of two adjacent
standards, measured
horizontally.
SCAFFOLD WIDTH
Distance between standards measured at
shortest point. (Board width)
Tied Scaffold
600 mm or 3 boards
Free standing scaffolds
1200 mm or 5 boards
38
HEIGHT
The height measured from the
foundation to the top assembly of
ledgers and transoms.
50 m un-sheeted & tied
25 m sheeted & tied
LENGTH
The length of a scaffold
between extreme
standards, sometime
designated by the
number of bays.
39
GUARD RAIL
A member incorporated in a structure to
prevent the fall of a person from a
platform or access way
470 mm max
1150 mm
150 mm
END GUARDRAIL
A guardrail placed across the end of a
scaffold or used to isolate an un
boarded part
40
TOE BOARD
An up stand at the edge of a platform
intended to prevent materials or
operatives feet from slipping off the
platform.
Min. 150 mm
Normally 225 mm
BRICK GUARD
A metal or other fender filling the
gap between the guardrail and toe
board and sometimes incorporating
one or both of these
components
41
WORKING PLATFORM
The deck from which work is being
carried out. Should be close boarded
TOWER SCAFFOLDS
LIGHT DUTY
ACCESS
(1.5 kN/m2)
42
FREE STANDING
TOWERS
MOBILE STATIONARY
TOWERS ERECTION SEQUENCE
43
TOWERS ERECTION SEQUENCE
TOWERS ERECTION SEQUENCE
44
TOWERS ERECTION SEQUENCE
TIES
When towers exceeds the height to least
base dimension, it should be tied or
anchored at least 6.0 m or less
A tie is the components attached to an
anchorage or the building or framed
around a part of it or wedged or screwed
into it with a tie tube. Used to secure the
scaffold to the structure
45
TYPES OF TIES - THROUGH
TYPES OF TIES - BOX
46
TYPES OF TIES - BOX
TYPES OF TIES - LIP
47
TYPES OF TIES – SCREW/
ANCHOR
SCAFFOLD TUBE
IN SIDE
STEEL WIRE
ROPE TIED IN
EYE
TYPES OF TIES – REVEAL
NO MORE THAN 50 % OF TIES (NOT RECOMMENDED)
48
RAKER
END OF CLASS
ROOM SESSION
NOW PRACTICALS
49