Practical Scaffold Training Manual
Part 1: Basic Scaffolding
Common Scaffolding Definitions
Basic Scaffold Requirements
Working Platforms
Side Protection and Principal Guard Rail
Access Between Levels
Load Classes and Actions
Materials
Scaffold Foundations
Ties
Manual Lifting & Handling
Ropes, Knots & Hitches
Raising & Lowering Materials
Obstacles & Hazards
Protective Fans
Part 2: Basic Scaffold Structures
Independent Tied Scaffolds
Putlog Scaffolds
Birdcage Access Scaffolds
Tower Scaffolds
System Scaffolds
Part 3: Amendment of BS EN 12811 :2003
Part 1
Basic Scaffolding
',"•
, .
COMMON SCAFFOLDING DEFINITIONS
Over the years scaffolders in different regional areas of the British Isles have evolved their own
terminology, their own particular names for the various types of scaffold and scaffold fittings in
common use. This chapter explains in simple terms the common names of the basic components, where they are placed in the structure and the job they do. At the end of this book you
will find a full glossary of the terminology used in the industry.
Standards (also known as uprights) are the vertical tubes which carry the entire load to the
ground. Each standard should have a base plate which, by spreading the load, prevents the end
of the tube from sinking into the ground.
The Base Plate is made from steel and has a central shank to locate the tube. Sometimes the
base plate is nailed or pinned to a sole board to stop lateral movement, particularly if no foot tie
or kicker lift is employed.
The Sole Board or Sole Plate is necessary, particularly on soft ground, as a means of spreading the weight over a greater area.
Standard
Ledgers are the horizontal tubes which connect and support the standards and act as supports
for transoms. The vertical spaces between ledgers are governed by the use for which the scaffold is intended.
Main Transoms are placed horizontally at right-angles across the ledgers, adjacent to each pair
of standards; or connected directly to each pair of standards. They hold both rows of standards
in position, help make the scaffold more rigid and also act as scaffold board supports.
Intermediate Transoms are placed across the ledgers between the main transoms and act as
scaffold board supports, sometimes referred to as 'board bearers'.
1
Cross or Ledger Braces are essential to the rigidity of the structure and are placed diagonally
across the ledgers, adjacent to alternate pairs of standards. Cross braces are normally fitted
directly on to the standards. Ledger braces are fitted to ledgers.
Dog-leg or zig-zag
ledger bracing
Cross braces
fixed with swivel couplers
to standards
Alternative
method
Facade or Sway Brace is a tube fixed to the face of the scaffold to stop the scaffold swaying. It
should run from the base to the full height of the scaffold at an angle of between 350 and 550
and be fixed at the base and at every lift level either to the standards or the ends of the transoms. One
such brace must be fitted every 4 bays or less along this face of the scaffold.
Fixed at every lift height either to standards
or ends of transoms
Bottom of brace should be grounded
Plan Bracing
•
•
•
•
•
If plan bracing is required it should be installed
Every 8m
Not more than 12 bays apart
Erected between ties.
Installed using doubles or if not swivels.
2
Scaffold Couplers There is a wide variety of couplers available and their use and maintenance
depends upon the type of fitting and its application. All fittings should be lightly oiled and kept
free from rust. The description and use of these items is covered in the chapter headed 'Materials'. An example is shown below.
Swivel Coupler
Joint Pins (or Spigots) are used to connect tubes end-to-end. The joint pin (spigot) is inserted
into the ends of the tubes and the centre bolt tightened, causing the two parts of the spigot to
expand and grip the inside of the tubes.
The fitting should not be used in positions where it will be subject to bending or tension.
Joint Pin (or Spigot)
Sleeve Coupler
Sleeve Couplers, generally called sleeves, are also used to connect tubes end-to-end. This
fitting has a resistance to bending, at least equal to any tube. It has a safe working tension of
315 kg.
3
'
I
rd Spacing (or bay length) is the distance between standards, measured along the
the scaffold.
e or Kicker Lift These are the ledgers and transoms that are fixed near to the bottom of
ds, approximately 150mm from the ground.
wor
part
con
me
and
ght or Ledger Spacing is the distance between ledgers, measured up the face of the
I.
ift or First Lift is the first lift above ground level, other than the foot tie or kicker lift.
No
dis
ac
as f
ers.
who
liabl
d Width is the distance between standards measured at the shortest point, also known
)Oard width.
1al terminology will be introduced throughout the book and will be explained as neces-
Bay length
1---
Sea
rials
ing
plet
ens
(par
the
at a
1
'
'
In th
asp
ings,
Base lift or
first lift
MA
Foot Tie or
Kicker lift
Mat
rust;
fittin
Lift height or
Ledger spacing
Bracing has been omitted for clarity
Boar
warp
defe
4
i
_l_
BASIC SCAFFOLD REQUIREMENTS
The primary reason for erecting a scaffold is to support a working platform. Most construction
work involves working at heights which cannot easily or safely be reached from the ground or
part of the building. By law, an employer must provide a safe working platform and a safe and
convenient means of access. All scaffolds are subject to the Provision and use of Work Equipment Regulations 1993 and BS 5973, the Code of Practice for Access and Working Scaffolds
and Special Scaffold Structures in Steel.
No scaffold should be erected, altered or
dismantled except under the supervision of
a competent and experienced person, and
as far as possible by experienced scaffold~
ers. Scaffolds erected or altered by people
who have no knowledge or experience are
liable to be dangerous and unsafe.
Scaffolds must be rigid, built of sound materials on good foundations and be well
secured to the building or structure. In
public places, scaffolds must be well lit or
have warning lights fitted at the base. Warning notices should be displayed on incomplete scaffolds and precautions taken to
ensure that no unauthorised persons,
(particularly children and other members of
the public), can gain access to the scaffold
at any time.
In this introduction to scaffolding requirements reference will be made to the various critical
aspects of scaffolds. Each subject is dealt with in greater detail under separate chapter headings, but is summarised below.
MATERIALS
Materials used to build a scaffold must be in good condition. Steel items should be free from
rust; fittings should be well serviced and free from excessive oil or grease which may cause the
fitting to slip.
Boards should be clean and in good condition; the ends bound or nail-plated, and not split or
warped and twisted. Scaffold boards should not be painted or treated in any way to conceal
defects.
5
i
Other materials, ropes, gin wheels, ladders, etc. must all be in sound, serviceable condition.
scaffolding materials must be inspected by an experienced and competent person, before us
and unsound and unserviceable materials clearly marked and removed from the site.
FOUNDATIONS
Thi
Autc
Che
Crar
Elev
Every scaffold structure must be well founded. The foundation must be capable of carrying th
imposed load for the entire lift of the scaffold. On hard surfaces, such as steel or concrete,
standards may be placed directly on the surface. On other surfaces, base plates and sole
boards must be used to spread the load. The ground beneath the sole board must be level a
properly compacted. This table shows the minimum requirements for bases to suit a range of
ground conditions.
FOOi
AmL
Tra
Crar
Safe
Safe
Ad vi
Basi
Cor
Cer
ISO
ISO
OHS
OS£
ISO/
Trair
Type
of
Base plate
spiked on
Base
¢
base
Ground
conditions
c:>
jl"::L
plate
stared on
225 mm X38 mm
plate
I: I:~::;;;': 225 mm
61.0 .mm long
m1mmum
~mmx
m
'
Timber steepar
Flat concrete,
Level stone,
Asphait surlaces
Load~bearing
Grass,
Ground (earth and
made up).
Pavement lights.
Stated or tiled roofs
brickwork or
similar good
surface
....
~
Base plate
and path,
Soft and/or loose
made up around
wet sites,
All heavy loaded
scaffolds on
earth surfaces
board x 225 mm
Timber
..
'',/
Dustsheet pack
Marble,
Mosaic,
Polished wood,
Carpets,
Lino, etc.
•
aola
spiked
on
o~
,."
~~· .,:
Standard not·:··
,
concrete block
River work,
Submerged
bases on
engineers
advice
THE SCAFFOLD FRAME
The framework of a scaffold is built from metal tubes of varying lengths, joined together with a
variety of couplers or clips (commonly called fittings). The actual design and shape of the stru
lure will depend on the type and intended purpose of the scaffold and the load it might be
expected to bear. This chapter is concerned with only the features of the structural framework
common to most scaffolds.
Intermediate
He
Ab1
Bra
Dul
Doi,
Mu:
Jub
i/Ve
6
Standards
Standards are the vertical element of the scaffold framework and as such carry the weight of
the structure and its load. Standards must be vertical.
The spacing of standards is determined by the intended use of the scaffold, the distance
between standards being reduced as he expected load increases. Table 1 (page 12) abstracted
from BS 5973 gives details of the maximum bay length (standard spacing) for different types of
scaffold; the most common being 2.1 m for a general purpose scaffold. This is reduced to 2 m
for a heavy duty scaffold and to 1.8 m for a scaffold being used for carrying out masonry and
stonework.
The width of the working platform, and thus the distance between the front and back rows of
standards is also determined by the purpose for which the scaffold is intended with a minimum
permissible width of 600 mm. This is usually expressed in terms of 'the number of boards wide'
for example a four-board scaffold would usually require a width spacing of 870 mm from centre
to centre of each standard. This measurement would only vary to accommodate different types
of couplers.
Joints in standards should be staggered, that is, joints should not occur at the same level in
adjacent standards. Joints can be made with spigots, but can be strengthened with lapped
tubes, or sleeve couplers, depending on the load.
/
/
/
/
I
1/
/
/
/.
I
I
II
/
'
I
,_
"/
I
v
/
I
I
,,~
I
,
/
..
'
"
.-
.
-.
·-
•
.-
.-
All joints should be staggered and kept as close to the node point (the junction of standard and
ledger) as practicable.
7
Ledgers
Ledgers are the main horizontal tubes and provide lateral support to the structure. They must be
level, and fixed to the inside of standards with right-angle, load-bearing couplers. The vertical
distance (lift height, ledger to ledger) should be 2 m and the base lift never more than 2.7 m.
Ledgers should be joined with sleeve couplers but internal joint pins (spigots) may be used if the
joint is within 300 mm of a standard; and should be as close to the point at which the ledger is
fixed to the standard as possible. They should never be more than one third of the bay width
from a standard. All joints must be staggered.
The kicker lift or foot tie should be set approximately 150 mm above ground level, except where
this is impossible for reasons of access. The kicker lift or foot tie is normally used only on heavy
duty or long term scaffolds, or where there is a possibility that standards could be displaced
through impact at low level.
H
2nd
Lift
1st
Lift
Standards
Ledgers
Transoms
Putlogs and Transoms
Main transoms are fixed, either directly across to every pair of standards, using right angle
couplers, or laid across and fixed to ledgers with putlog couplers. In this case, transoms should
be fixed as close as possibly, but never more than 300 mm from each pair of standards. Main
transoms hold the two rows of standards in position, are an integral part of the structure and
must not be removed unless expert advice is sought.
A putlog is the name given to the horizontal tube used when there is only one row of standards.
One end of the putlog is fixed to the scaffold in the same way as a transom, while the other end
is supported directly by the structure against which the scaffold is being erected. This is generally brickwork.
8
Transoms or putlogs should never be laid more than 1.5 m apart when used as supports for 38
mm scaffold boards or 2.6 m for 50 mm boards. The length of the putlog or transoms will be
determined by the width of the proposed platform, which in turn will be decided by the use for
which it is intended with a minimum width of 600 mm.
Main Transoms
Intermediate Transoms
Intermediate Transoms
If the lift is to be boarded over as a working platform, intermediate transoms will be required to
support the boards. These are fixed across ledgers with putlog couplers, normally in the centre
of each bay, although additional intermediate transoms may be required to support short
boards. They may safely be removed and used elsewhere in the structure when the platform is
no longer required.
Ties
To ensure that the scaffold framework cannot move away from, or towards the structure, it must
be stabilized. This is normally achieved by securing the scaffold framework to the building with
positive two-way ties.
Ties must not be removed, except by an experienced and competent scaffolder, who must
ensure that the stability of the scaffold is not jeopardised. If removed for access or any other
purpose, alternative ties must first be fixed to maintain the stability of the scaffold.
Ties must be checked at regular intervals, and re-checked again before dismantling.
Braces
All scaffold structures must be braced in both directions. Facade (or sway braces) should be
fitted along the outer face of the scaffold, from the base to the full height of the structure. In the
case of large structures a brace must be fixed every 30 m or less along the face and can be
continuous or placed across each bay in a zigzag (dog-leg) fashion. Joints in facade braces
must be made with sleeve couplers. If joint pins (spigots) are used each joint must be strengthened with a lapped tube.
9
Braces must be connected at every lift to standards using swivel couplers, or to the ends of
transoms with right-angle couplers, in which case the transom itself must be fixed with right-angle couplers.
All braces form an integral part of the scaffold structure and must not be removed without advice
from a competent scaffolder.
Ledger Bracing
Continuous Facade or Sway Braces
Dog-leg Bracing
Working Platform
As previously indicated, the primary purpose of a scaffold is to provide support for a temporary
working platform. The law requires that as regards any place of work it must be safe for the user
and not expose anyone else to any risk to their safety or health (i.e other tradesmen and members of the public).
If the platform is 2 m or more above the ground, it must be close boarded and be fitted with
guard-rails and toe-boards (including stop ends). If materials are stacked on the platform above
the height of the toe-board, a suitable barrier (such as a brick guard) must be erected to prevent
the materials from falling off.
The width of the working platform, which must be a minimum of 600 mm, and the uses for which
they are designed are detailed in the tables which follow this chapter .
The width platform must be provided with a means of access that is safe and without risk. This
is usually a ladder. It must be properly secured and extend 1.0 m above the working platform
(this equates to 5 rungs) unless other adequate hand-holds are provided. Landing areas must
be fitted with guard-rails and toe-boards and should be kept clear. (See chapters on ladders and
working platforms).
10
Oversail
approx.
600mm
Puncheon as
a handhold
Guardrails
Close
boarded platform
Loads on Scaffolds
Care must be taken to see that any load does not exceed the permissible limits (see Table 1 for
details of distributed loads). Materials should be distributed as evenly as possibly with heavy
items, bricks, etc. stacked near to standards.
11
DUTY CLASSES ACCORDING TO BS 5973
Table 1. Access and working scaffolds of tube and couplers
Duty
Use of Plateform
Distribute
load on
platforms
KN/m2
Maximum
number of
platform
Commonly used widths
using 225 mboards
Max. bay
length m
lnspetion, painting
stone cleaning, light
cleaning, cleaning and
access
0.75
1 working
platform
3 boards
2.7
Light duty
Plastening, painting,
stone cleaning,glazing
and pointing
1.50
2working
platform
4 boards
2.4
General
purposes
General building work
including brickwork
window and mullion
fixin~, rimdering,
plas ernng
2.00
2 working
platforms +1 at
very light duty
5 boards or
4 boards +1 inside
2.1
Heavy duty
Bolckwor~ brickwork
heavy cal ding
2.50
2 working
platforms + 1 at
very light duty
+ 1 inside or 4 boards
+ 1 inside
5 boards or 5 boards
2.0
Masonry or
special duty
Masonry work, concrete
blockwork, and very
heavy cladding
3.00
1 working
platform + 1 at
very light duty
6 to 8 boards
1.8
Table 3. Maximum span of scaffold boards
Purpose
Minimum width (using
225 mm nominal
width board}
Nominal
thickness of
boards
For access, Inspection,
gangways and runs
600mm
Working platforms for men
without materials or only for
the passage of materials
For men and materials
provided 440 mm left clear
for passage of men or
640 mm if barrows are
used
For carrying restles or
other similar higher
platforms
For use in dressing or
roughly shaping stone
640mm
3 boards
mm
38
50
63
870mm
4 boards
1.07 m
5 boards
1.3 m
6 boards
1.5 m
7 boards
For use to support a higher
platform where supporting
scaffold is also used for
dressing and roughly
shaping stone
Maximum
span between
transoms
Minimum
overhang
Maximum
overhang
m
1.5
2.6
3.25
mm
50
50
50
mm
150
200
250
Reproduced from BS 5973: 1993
with approval of British Standerds Institution
These scaffolds should be specially designed
12
I
I
Inspection
and very light
duty
Table 2. Widths of access scaffold
platforms
I
I'
I
Width Classes
The width, w, is the full width of the working area including up to 30 mm of the toeboard, Seven
width classes are given in Table 1.
NOTE 1 In some countries minimum widths are laid down for various types of work activity.
The clear distance between standards, C, shall be at least 600 mm; the clear width of stairways
shall not be less than 500 mm.
Each working area, including the corners, shall have its specified width along its full length. This
requirement does not apply in the immediate vicinity of a pair of standards, where there shall be
a completely unimpeded area with a minimum width, band p in accordance with the dimensions
given in the next Figure.
NOTE 2 When equipment or materials are placed on the working area, consideration should be
given to maintaining space for work and access.
Table 1 - Width Classes for working Areas
w
Width Class
inm
W06
0.6,,; w > 0.9
W09
0.9,,; w > 1.2
W12
1.2,,; w > 1.5
W15
1.5,,; w > 1.8
W18
1.8,,; w > 2.1
W21
2.1,,; w > 2.4
W24
2.4,,; w
Headroom
The minimum clear headroom, h3 , between working areas shall be 1,90 m.
The headroom requirements for the height h 18 between working areas and transoms or for the
height h1b (see next figure) between working areas and tie members are given in Table 2.
Table 2 - Headroom Classes
Clear Headroom
Class
H1
Btween working areas Btween working areas
and transoms or tie
members
Minimum clear height at
shoulder level
hs
h1a• h1b
h2
h3>1,90m
1. 75 m ,,; h1 a < 1 ,90 m
h2 ;;:1.60m
1.75 m ,,; h1b < 1,90 m
H2
h2> 1,90 m
h1a ;;: 1,90 m
h1b;;: 1,90 m
13
h2 :2:1.75 m
Dimensions in millimetres
> 150
,,,
_,_ -:i:-~ p
'
I '"'ii"' I
"
_J
~
/'
~
L-
,.., i
I
~
I
0
0
"'Ill
~
.c•
.a·
.c
I
y
,,
D·~
N
.<::
I
"'
.<::
I
I
b
I
I
1,-L.r- .__....,,
-
w
r---
__J
b_
-
c
KEY
b =free walking space, which shall be at least th greater of 500 mm and (c-250 mm)
c = clear distance between standards
h1a h b =clear headroom between working areas and transoms or tie membes respectively
1
1
h2 = clear shoulder height
h3 = clear headheight between working areas
p =clear headheight width, which shall be at least the greater of 300 mm and (c-450 mm)
w = width of the working area .
Requirements for headroom and width of working areas
Working Areas
a)
It shall be possible to secure platform units against dangerous displacement e.g.
unintended dislodging or uplifiting by wind forces.
b)
Platform units should have a slip-resistant surface.
NOTE A timber surface normally meets the requirements for slip-resistance. The risk of tripping
from any method used to secure the platform unit or from overlapping should be minimised.
c)
The gaps between platform units shall be as small as possible but not exceeding 25 mm.
d)
Working areas shall be as level as practicable. If the slope exceeds 1 in 5, securely
attached full width footholds shall be provided. Except that, where necessary, there may be
gaps not exceeding a width of 100 mm in the centre of the footholds to facilitate the use of
wheebarrows.
Side Protection
General
Working and access areas shall be safeguarded by a side protection consisting of at least a
principal guardrail, intermediate side protection and a toeboard. The toeboard may be
dispensed with on stairways.
Side protection shall be secured against unintended removal.
NOTE 1 The side protection should not be provided by cladding on its own.
NOTE 2 For special cases e.g. use of working scaffolds in vertical formwork there may be a
need of inclined side protection, which is outside the field of application of this standard.
Dimensions in millimetres
<80
:;>80
~
0
....
""
/\I
E
-$0
....""
/\I
I
0
l{)
~
/\I
Dimensions for vertical side protection with one intermediate guardrail
15
pal Guardrail
rincipal guardrail shall be fixed so that its top surface is 1 m or more above the adjacent
>f the working area everywhere (absolute minimum height 950 mm).
nediate side protection
iediate side protection shall be fixed between the principal guardrail and the toeboard.
iediate side protection may consist of:
or more intermediate guardrails, or
1me, or
1me of which the princiapal guardrail forms the top edge, or
1cing structure
ings in the side protection shall be so dimensioned that a sphere with a diameter of 470
1ill not pass through them.
oard
board shall be fixed so that is at least 150 mm above the adjacent level of the working
Holes and slots in a toeboard shall, except for handling holes be no larger than 25 mm in
lirection.
:ing Structures
~rea of each hole or slot in fencing structures shall not exceed 100 cm . In addition, the
2
ontal dimension of each hole or horizontal slot shall not exceed 50 mm.
1tion of the components of the side protection
horizontal distance between the outer face of the toeboard and the inner face of the guard1nd all the components of the intermediate side protection shall not exceed 80 mm.
lding
:re cladding of the working scaffold is required, this standard assumes that the scaffold will
lad with either netting or sheeting.
e plates and base jacks
strength and rigidity of the base plates and base jacks shall be sufficient to ensure that it
transmit the maximum design load from the working scaffold to the foundations. The area of
end plate shall be a mimimum of 150 cm'. The minimum width shall be 120 mm.
I
- ·-•-.a.-- _... ... ..a,,. ..,.f L!-tal!llll ~h~ll ~nnfnrm tn EN 74.
j
Joints between standards with hollow sections
The overlap length in joints between standards shall be at least 150 mm. It may be reduced to a
minimum of 100 mm if a locking device is provided.
Access between levels
General
Safe and ergonomic means of access shall be provided.
The scaffold system shall include provision for access between the different levels. This shall be
by inclined ladders or stairs. It shall be within the platform, within a widening of the working
scaffold at one bay or in a tower immediately adjacent.
Ladders in accordance with EN 131-1 and EN 131-2 may be assumed to satisfy the requirements for access in this standard.
The stairways and ladders shall be secured against unintentional loosening and shall have a
slip resistant surface.
NOTE 1 When extensive work is carried out, stairways should be provided for access.
NOTE 2 For taller scaffolds consideration should be given to the use of a passenger hoist.
Stairways
To cater for different requirements for stairways this European Standard specifies two classes of
stairway dimensions. The dimensions of stair flights shall be in accordance with the following:
The combination of values for the rise, u, and the going, g, shall be in accordance with expression (1):
.',,
540 s 2u + g s 660 in mm
Dimensions in millimetres
2
L!)
gJ
Stairway dimensions
Dimension
VI
::J
Class
VI
A
B
mm
mm
s
125 s s s165
s ~165
g
~15,; g <175
g ~ 175
:e
~
Minimum clear width 500 mm
s
g
Stairway dimensions
17
-25 s as 55
Access Openings
The clear dimensions of an access opening in a platform shall be at least 0.45 m wide, measured across the width of the platform, and 0.60 m long. Should it not be possible to close the
opening by means of a permanently attached trapdoor, it shall be possible to install a protective
railing. The trapdoor shall be fastenable in the closed position.
Requirements for structural design
Basic requirements
General
Each working scaffold shall be designed, constructed and maintained to ensure that it does not
collapse or move unintentionally and so that it can be used safely. This applies at all stages,
including erection, modification and until fully dismantled.
The scaffold components shall be designed so they can be safely transported, erected, used,
maintained, dismantled and stored.
External Support
A working scaffold shall have a support or foundation capable of resisting the design loads and
limiting movement.
Lateral stability of the scaffold structure as a whole and locally shall be verified when subjected
to the different design forces, for example from the wind.
NOTE 1 Lateral stability can be provided by tie members to the adjacent building or structure.
Alternatively other methods, such as gy ropes, kentiedge or anchors may be used.
NOTE 2 It may be necessary to remove individual ties temporarily in order to carry out work on
the permanent structure. In such a case removal of the ties should be taken into consideration
in the design and a method statement prepared specifying the sequence for removal and
replacement of ties.
Load Classes
To cater for different working conditions, this European Standard specifies six load classes and
seven width classes of working ares. The service loads are set out in Table 3.
The load class for working areas shall correspond to the nature of work.
NOTE In exceptional cases, where it is impractical to adopt one of the load classes or the
activity is more onerous. Different parameters may be adopted and specified after analysis of
the use to which the working scaffold will be put. Consideration should be given to the actual
activities to be undertaken. Some examples of items to be considered are:
a) The weight of all equipment and materials stored on the working area.
b) Dynamic effects from material placed on the working area by powered plant and
c) Load from manually operated plant such as wheel barrows.
18
Table 3 - Service loads on working areas (see also 6.2.2)
Load
Class
Uniformly
dlstrubuted
load
Concentrated load
on area
500 mm x 500 mm
Concentrated load
on area
200 mm x 200 mm
q1
kN/m 2
F1
F2
kN
kN
0.752
1.50
2.00
3.00
4.50
6.00
1.50
1.50
1.50
3.00
3.00
3.00
1.00
1.00
1.00
1.00
1.00
1.00
1
2
3
4
5
6
Partial area load
q2
kN/m2
---5.00
7.50
10.00
Partial area
factor
ap1
---
-0.4
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Actions
General
There are three main types of loading which need to be considered:
a) Permanent loads; these shall include the self weight of the scaffold structure, including all
components, such as platforms, fences, fans and other protective structures and any ancillary
structures such as hoist towers.
b) Variable loads; these shall include service loads (loading on the working area, loads on the
side protection) and wind loads.
c) Accidental loads.
Loading on the working area
General
The service loads shall be as specified in Table 3. Each working area shall be capable of supporting the various loadings, q 1 , F1 and F2 , separately but not cumulatively. Only the uniformly
distributed load, q 1 , has to be carried down to the support of the scaffold structure, for birdcage
scaffolds the partial area loads also.
For the purposes of structural design, service loads on the working area shall be applied over
an area determined as follows:
- Where there are contiguous platforms along or across the working scaffold, the dividing edge
shall be taken as a centreline between the supporting standards.
- At any outer edge the dimension, w, shall be taken to the actual edge or, where there is a
toeboard.
For working scaffolds of load class 1, all platform units shall be capable of supporting class 2
service load, but this shall not apply to the scaffold structure in its entirety.
Uniformly distributed service load
Each working area shall be capable of supporting the uniformly distributed load, q 1 , specified in
Table 3.
19
Concentrated load
Each platform unit shall be capable of supporting the load, F1 , specified in Table 3, uniformly
distributed over an area of 500 mm x 500 mm and, but not simultaneously, the load, F , speci2
fied in Table 3, uniformly distributed over an area of 200 mm x 200 mm.
The load path shall be capable of transferring the forces caused by the loads to the standards.
The position of each load shall be chosen to give the most unfavourable effect.
When a platform unit is less than 500 mm wide, the load, F1, according to Table 3, may be
reduced for this unit in proportion to its width, except that in no case shall the loading be
reduced to less than 1.5 kN.
Partial area load
Each platform of load class 4, 5 and 6 shall be capable of supporting a uniformly distrubuted
partial area loading, q2 , which is a loading greater than the uniformly distributed service load.
The partial area is obtained by multiplying the area of the bay, A, by the partial area factor ap.
Vales of q2 and ap are given in Table 3. The area A is calculated from the length, I, and the
width W, of each platform, see next Figure.
The load path are more than two standards in both directions, as in a birdcage, the partial area
loads of four contiguous bays shall be considered for the verification of the respective supporting standard. The dimensions and position of the partial area shall be chosen to give the most
unfavourable effect. Some examples are shown in Figure 5.
M max; 0 : max
Vmax
lxa
lxa
-=··=··3.~
a=1
a=a P xw
b1
a) Platform *) or platform unit**): longitudinal span
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20
1
M max; o: max
Vmax
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b) Leder: Transverse span of the platform
M max; V max: 0 max:
I
c) Transom: Longitudinal span of the platform
N max:
d) Central standard of a birdcage scaffold
Key
system length
width of the platform
partial area factor, see Table 4
width of the platform unit
M max
Vmax
N max
()max
maximum bending moment
maximum shear force
maximum axial force
maximum deflection
Examples for the positioning of the partial area load for the calculation
of some structural components
\
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21
Materials
General
Materials shall fulfil the requirements given in European Standards, where design date are
provided.
Information for the most commonly used materials in given in BSEN 112811-2. Material used
shall be sufficiently robust and durable to withstand normal working conditions.
Materials shall be free from any impurities and defects, which may affect their satisfactory use.
Specific material requirements
Steel
General
Steels of deoxidation type FU (rimming steels) shall not be used.
Loose tubes
Loose tubes to which it is possible to attach couplers complying with BSEN 74-1 (i.e nominal
48.3 mm outside diameter) shall have a minimum nominal yield strength of 235 N/mm2 and a
minimum nominal wall thickness of 3,2 mm.
NOTE Loose tubes are usually found in tubes and couplers scaffolds but can also be used in
facade scaffold made of prefabricated components e.g. to tie a working scaffold to the facade.
Tubes for prefabricated components for scaffold systems
For tubes incorporated in prefabricated components for scaffold systems according to EN
12810-1 of nominal outside diameter of 48.3 mm the specifications of EN 12810-1 apply.
Tubes shall not be indented beyond the limits in BSEN 74-1 when couplers are attached.
Tubes of external nominal diameter different from the ragne of 48,3 mm, other than side protection, shall have the following nominal characteristics:
;::: 2.0 mm
- wallthickness
- yield stress, RaH ;::: 235 N/mm 2
;::: 17%
- elongation, A
i
Side protection
I
Items used exclusively for side protection, other than toe-boards, shall have a minimum nominal
wall thickness of 1,5. For toeboards the minimum nominal wall thickness shall be 1,0 mm. A
lesser thickness may be used if the serviceability and load bearing capacity is ensured for
instance by the use of stiffening sections, bracing or shaping of the cross section.
Platform units
Platform units and their immediate supports shall have a minimum nominal thickness of 2,0 mm.
A lesser thickness may be used if the serviceability and load bearing capacity is ensured for
instance by the use of stiffening sections, bracing or shaping of the cross section.
22
Protective coating for components
Components shall be protected as determined in BSEN 12811-2.
Aluminium alloys
Loose tubes
Loose tubes, to which it is possible to attach couplers complying with BSEN 74-1 (i.e 48,3 mm
nominal outside diameter), shall have a minimum nominal 0.2% proof stress of 195 N/mm2 and
a minimum nominal wall thickness of 4,0 mm.
Tubes for prefabricated components for scaffold systems
For tubes incorporated in prefabricated components in scaffold systems according to EN
12810-1 of nominal outside diameter of 48,3 mm the requirements of EN 12810-1 apply.
Side protection
Items used solely for side protection shall have a minimum nominal wall thickness of 2.0 mm. A
lesser thickness may be used if the serviceability and load bearing capacity is ensured for
instance by the use of stiffening sections, bracing or shaping of the cross section.
Platform units
Platform units and their immediate supports shall have a minimum nominal thickness of 2,5 mm.
A lesser thickness may be used if the serviceability and load bearing capacity is ensured for
instance by the use of stiffening sections, bracing or shaping of the cross section.
Timber and timber based materials
Timber shall be stress graded in accordance with EN, 338.
If a protective coating is used, it shall not prevent the discovery of defects in the material.
Plywood for platform units shall have at least five plies and a minimum thickness of 9 mm.
Plywood platform units assembled ready for use shall be capable of retaining a circular steel bar
of 25 mm diameter and 300 mm length falling endwise from a height of 1 m.
Plywood shall have a good durability with regard to climatic conditions.
23
['
'
Inspection
The ability of a scaffold to carry its load is largely dependent on the strength and condition of the
tubes used in its construction. Consequently, tubes must be checked to ensure that are:
*
*
*
Straight
Free from cracks, splits, bad dents and excessive corrosion
Cut square and clean at each end
Common Faults
Mushroom headed tube
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. Wherever possibly tubes should be sorted
according to length and stored in racks with their ends flusk. This makes it easier to identify and
select tubes of the length required.
Inspection and Maintenance
Care should be taken of boards in use. No overstressing should be allowed, e.g. that caused by
impact loading. Boards being used as ramps or as platforms over long spans should be supported regularly; they should not Supportbe placed where vehicular or other loads can be put
on them. Boards showing any evidence of damage from vehicles, e.g. tyre marks, should be
destroyed.
24
Scaffold boards should be cleaned and the hoop irons or nail plates secured or replaced if
necessary. Split boards may be cut down or repaired using nail plates depending on the degree
of damage. No cut outs, burns, oil stains or projecting nails should be present and boards found
having any of these should be discarded.
Boards should not be painted or treated in any way that may conceal defects, but can be
fireproofed using an approved material.
Common Faults
Storage
Scaffold boards should be stacked no more than 20 high with stacks separated by short timber
battens, and placed on level timbers, off the ground, for protection from surface water. Boards
should be protected from weather and have a free circulation of air
',
Roof shown cut away for clarity
25
'1
SCAFFOLD COUPLERS
Sometimes called scaffold 'fittings' these are designed and tested to British Standard specifications. Because of the diversity of design, many fittings achieve higher SWL (safe working loads)
than those laid down by the British Standard and it would be impossible and improper to quote
the different company fittings and values. All SWLs and values quoted in this manual are those
specified by the British Standard.
Right-angle Couplers, also called Doubles,
are always used to connect ledgers to standards. They are designed and tested to
achieve a right-angled connection with a
minimum safe working load of 635 kg.
Putlog Couplers, also called Clips and Singles, are used to connect transoms to ledgers; they
are only suitable for light duty use (sometimes referred to as non-load bearing). They must be
capable of passing the slip test as specified by the British Standards.
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Swivel Couplers, are used to connect tubes at any angle; normally used to connect braces to
standards and occasionally to make parallel joints. Swivel couplers should never be used as
right-angle couplers.
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26
Inspection and Maintenance
Scaffold fittings must be inspected by an experienced and competent scaffolder before use. Any
broken or damaged fittings should be discarded, as should any with damaged threads. Rusty
threads (if not defective) should be wire brushed and lightly oiled.
Scaffold fittings should be sorted by type, and kept clean and dry in strong sacks, lightly oiled to
prevent rust. Care should be taken to see that each sack contains only the limited quantity of
fittings which can be handled with ease - usually no more than 30 fittings to a sack. Reference
shall be made to the Manual Handling Regulations to ensure excessive weight is not required to
be handled.
MANAGEMENT OF MATERIALS
Materials must be delivered to site when required and removed and stored when the job is
finished. Ensuring that the correct amounts and types of materials arrive at the right place and
the right time needs careful planning and organisation. This is normally provided by the scaffolding depot where these materials are stored. The management of depots is not within the scope
of this book, but is referred to in the chapter on the Organisation and Working Methods.
SCAFFTAG
INCOMPLETE SCAFFOLDING
A scaffold should be constructed so that it is left complete and is properly tied, braced and
decked and has adequate guard-rails and toe boards. Where a scaffold is left incomplete there
is a danger that it will be used to gain access while it is in a dangerous consition. Where a
scaffold is partly erected or dismantled, a prominent warning notice should be placed at each
potential access point and barriers should be placed to prevent access.
Such notices should be removed when they are no longer required.
The most effective way of preventing access to an incomplete scaffold is by removing· all
decking and ladders. Incomplete scaffolds should be completed or dismantled as soon as
practicable.
For that we have to use Scafftag in every access to tell about the condition of the scaffold
whether it is ready to use or not,
RED SCAFFTAG: Do not use the scaffold.
GREEN SCAFFTAG: Ready to use, date of erection, SWL.
YELLOW SCAFFTAG: Validity of the scaffold is
finished and it needs to be re-inspected.
27
:FOLD FOUNDATION
tructure, whether it be a house or a multi-storey block of flats, must have foundations
)le of carrying the load safely for its entire life. This also applies to scaffolds. The foot of
tandard or upright must be adequately founded on a suitable base plate in order to prevent
ng or sinking; or its displacement shall be prevented in some other way.
NDATIONS
neral the foundations for a scaffold must be adequate to carry and spread the load
sed, both locally at each standard, and to collectively carry the whole weight of the scaffold.
he responsibility of the scaffolder to ensure that the foundations are of adequate strength to
>ort the scaffold, but in practice this is done in consultation with the scaffolding sub-ractor.
foundation for a scaffold must be maintained in an adequate condition during the life of the
fold.
1e Plates
d surfaces - such as steel and concrete. Where there is a sufficient strength and thickness
rnvent the scaffold tube penetrating into the surface, the uprights of a scaffold may be
;ed directly on the surlace, although it is recommended that base plates should always be
:d.
rfaces of intermediate hardness - such as pavements, hard asphalt, timber and flooring.
1ere there is a possibility of the standards deforming the surface, base plates or metal packplates should be used at the bottom of each standard.
le Boards
any type of flooring or paving which would be penetrated by a standard with a base plate
neath it, or if there is doubt about the surlace, there should be a further spreading of the load
a sole board of timber or other suitable material.
1
hen a sole board is used, the sole board beneath any one standard should be at least 1,000
12, with no horizontal dimension less that 22 cm. If the sole board is of timber, it should not be
ss than 3.5 cm thick. On sites where the ground is soft or has been disturbed, the total area of
1ch sole board should not be less than 1,700 cm2 when used under individual standards (e.g.
ider hoist towers) and not less than 3,400 cm2 when combined under two standards. In this
1se, if the sole board is of timber, it may be necessary for this to be more than 3.5 cm thick.
eavy duty scaffolds and poor ground will require stronger foundations.
These are minimum requirements; in practice they can be interpreted as follows
*
*
*
on firm ground - 500 mm long x 225 mm x 35 mm
on soft ground - 765 mm x 225 mm x 35 mm
under two standards - 1.55 mm long x 225 mm x 35 mm
Soil Compaction
The soil or ground beneath the sole board should be well compacted and free from irregularities
which would make the sole board unstable or poorly bedded. On slopes exceeding 1:1 O a check
may have to be made on the stability by a qualified engineer before erecting a scaffold.
DANGEROUS PRACTICE
Trench
BAD PRACTICE
It is clear that each standard is incorrectly founded (based). Unfortunately, these faults are
found on many construction sites and can cause scaffolds to collapse, resulting in injury or
death.
1.
The board has not been properly bedded. It is too long and has been struck by a fork-lift
or dumper truck, which has knocked it off-centre.
2.
Again, board too long; no base plate.
3&4. Were correct, until somebody dug the trench! As it is, the edge of the trench could
crumble or the boards bend and possibly break.
5&6.
Quite simply these are not sole boards. The thermal block (5) will crack and (6) is near
to useless.
29
I
---~-_'._._-----~
Ledger
50mm thick
Sole boards
Trench
This diagram shows the correct method for founding the scaffold shown on the previous page.
Note that cross braces have been added to transfer loading away from the base of those standards which are near the trench.
BASIC RULES
1. The ground must be capable of supporting the scaffold.
2.
The sole boards must be capable of spreading the weight of the structure without distortion.
3.
Two standards per sole board are better than one.
4.
Sole boards placed at right-angles to the building should not project too far beyond the face
of the scaffold.
5.
Sole boards should not be undermined.
30
Heavy-duty Foundations
Illustrated below is a typical arrangement for a multi-storey independent scaffold. Railway sleepers have been set into a shallow bed of concrete with base plates pinned to the sleepers. The
standards have been further supported with a kicker lift at the base of the scaffold. All the connections have been made with right-angle couplers directly to the standards for additional rigidity and strength.
Nailed to Sole Board -
Set in Concrete
Note: Fittings, Braces and Intermediate Transoms have been left out for clarity
Before heavy-duty foundations are laid, consideration should be given to any proposed adoptions that may be required during the life of the scaffold as this may affect the position of the
sole boards. For instance, it may be necessary to add double standards at the base of the
scaffold. In this case sole boards should be placed parallel to the building and be long enough
to accommodate the extra standards. Bridging may be necessary for vehicular access. Sole
boards should be placed at right-angles to the building at the appropriate places to accommodate this.
1
j
31
Pavement Scaffold Foundations
The next illustration identifies some of the problems facing a scaffolder when trying to found on
a pavement. Apart from the normal problems of founding, it may be necessary to remove the
base lift braces for public access. Consideration should be given to the need for additional ties
near the base.
The illustration highlights some of the difficulties which can be avoided with foresight. If the
pavement surface is tarmac, every standard should have a sole board.
Sometimes pavement lights may have been covered with tarmac and it is important to check
this. Pavement slabs are normally adequate to take the weight of access scaffolds.
DANGEROUS PRACTICE
Inspection z_~~;......,::;::::-­
Covers
Pavement
lights
Light duty access scaffolds can be founded on pavements, without sole boards, provided the
pavement is capable of supporting the scaffold, ie. paving slabs of a continuous concrete
paving.
32
lations on Sloping Ground
1ows a good example of a well-founded base, on sloping ground. The standards are
rted by a tie ledger which is connected to the ends of the transoms with right angle couBase plates are positioned in the centre of the sole boards, which in turn have been laid in
JI 'steps' in the bank.
transom to
standard
Good rule of thumb
to allow for erosion or
minor subsidence
225mm : 225 mm
--·~
NOTE
Braces have been omitted for clarity
..
>llowing illustration shows typical examples of inadequate and unsafe sloping foundations.
®
THIS DIAGRAM DEPICTS
Minor subsidence or
DANGEROUS PRACTICE
steeper than 1 :1 O
be checked for
, by a qualified engineer
erecting a scaffold.
erosion renders
foundation useless
Base plate and sole board
Sole board not fully founded on levelled ground
TIES
STABILITY
Scaffolds are often erected to substantial heights, and to ensure the stability of the scaffold it is
necessary to tie it to the adjacent structure. The system of tubes which prevent movement either
towards or away from the structure is referred to as a tie.
GENERAL RULES
Ties usually pass through the facade of the structure and should be secured to the scaffold with
load-bearing right-angle couplers, as close to a node point (the junction of standard and ledger)
as possible. In certain cases the tie may not be at right angles to the structure in which case
swivel couples may be used. At least half of the ties should be 'positive' two-way ties; that is
they should prevent movement both towards and away from the building, and not depend on
friction or merely restrict movement in one direction.
It is important to ensure that the building is strong enough to sustain the load which will be
transferred to it via the tie. Parapets or decorative architectural features, balustrades, railings,
etc. are seldom strong enough for this purpose and should not be relied upon.
The tie tube should always be horizontal or slope slightly downwards away from the building,
and preferably be attached to both standards, or to both ledgers at a point not more than 300
mm from a braced standard.
Where wire or banded ties are used they should be turned round a node point or otherwise be
prevented from slipping along a ledger or upright by fixing safety couplers either side of the
point of attachment; and butt transoms should be used in addition. A butt transom, as the name
implies, being one which butts hard up against the structure being served by the scaffold.
NUMBER AND POSITION OF TIES
Scaffold ties should be fixed every 25 m2 of the face area and be evenly spaced, both horizontally and vertically, at least every 6 m. For independent scaffolds where ties will not be removed
the spacing may be increased to one tie every 40 m2 evenly spaced. It should be remembered
that the figures above are the minimum requirements on reasonably standard scaffold, and that
it is often wise to put in additional ties.
The basic rules of thumb worth remembering are:
*
Space ties every other lift and every 6 m along the face of the scaffold.
*
Ties should be fixed with load-bearing couplers, as close to the node points as possible
*
Avoid the use of reveal ties where possible. At least half of the ties on a scaffold must
be positive.
*
Take full advantage of structural features of the building e.g. pillars, columns, lintels,
rebates, etc. to provide additional strength and stability to the tie.
34
*
Make sure that the building is strong enough to support the tie and the load imposed on
it by the scaffold
*
Do not remove a tie for any reason until the overall stability of the scaffold has been
confirmed
For scaffolds greater than 50 m high, the number and position of ties will be one of the design
factors to be decided by a scaffold design engineer, and as such is outside the scope of this
book.
Ties for Sheeted Scaffolds
Scaffolds fitted with sheeting, tarpaulins, etc., will be subjected to extra stress due to wind
forces and will require more ties. In cases where ties may be temporarily moved they should be
spaced at not less than one tie every 25 m2. Where there is no possibility of the tie being
removed, this may be increased to one every 32 m2.
In exposed locations or in places where high winds are likely, and where the scaffold is more
than 25 m high, special calculations must be made to assess if closer spacing is required. This
should be undertaken by a scaffold design engineer and is outside the scope of this book.
),
f
TYPES OFTIE
I'
THROUGH TIES
Through ties rely on a tube (the tie tube) passing through any convenient opening in the building, (such as a window or door opening) coupled to an inside tube spanning the opening. This
inside tube should preferably be vertical, resting on the floor so that it cannot slip, but may be
placed horizontally. If possible the tie tube should rest on a sail or other convenient ledge to
avoid slipping but may be placed under the lintel; the basic principle being to derive as much
support and security from the building as possible.
Through ties must be positive, two-way ties, preventing movement both towards and away from
the building. Where it is not possible to fix a bridle tube (the outer horizontal tube spanning the
wall opening, the adjacent transoms should butt against the outer surface of the wall.
On a putlog scaffold, where the putlogs are required to support boards, a bridle tube is
frequently placed near the wall across adjacent putlogs either side of a wall opening. This
arrangement can serve as a through tie, by extending a putlog inwards and connecting it to a
horizontal (or vertical) tube inside the wall. In this case, load-bearing, right-angle couplers
should be used to secure the tie tube, which should pass below the ledger for two reasons.
First, the right-angle, load-bearing couplers used are bulkier than simple putlog couplers and
would prevent scaffold boards from laying flat. Second, it is better if the tubes are not used as a
direct support for a working platform as the weight and vibration of the platform imposes extra
unnecessary stress on the tie tube.
L
35
Ir,'iI
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THROUGH TIE (Couplers not shown for clarity)
Through has should be placed
as close as possible to the
window reveal and ascured
with right-angle couplers
Box Ties
These ties take advantage of the physical characteristics of a building and consist of an assembly of tubes and couplers fixed around convenient columns and other features of the building,
being wedged where necessary to resist both the inward and outward pull of the scaffold and to
provide additional lateral stability.
Box ties should be set preferably at lift level and be secured to both inside and outside ledgers
on standards unless this is likely to obstruct free access through the scaffold, in which case they
may be fixed to a single inside standard. Load-bearing couplers should be used.
BOX TIE
36
!S
it is not possible to use box ties, lip ties may be used instead. These consist of an L-j arrangement of tubes and couplers to hook behind a convenient part of the building of
~te strength. As such they only restrain an outward movement of the scaffold and should
forced by an adjacent butting transom or similar arrangement to restrict inward move_ip ties contribute little or nothing to the lateral stability of the scaffold and a sway transom
itional bracing may be required.
~·A
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-
-
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Column
Column
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Column
.
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t
Double-lip
or U-tie.
Box tie
~
..
Column tie with
Butt transom
r or Anchor Ties
ie cases it is possible to 'build in' scaffold ties into the fabric of the building during its
uction. A variety of screwed plates, sockets and nuts are available for setting into conduring pouring, for subsequent use as the anchor for a tie.
1r sockets and ring bolts are also available for fixing into holes drilled into hardened conx brickwork. When drilling into brick, however, care must be-taken to drill into the body of
ick, not near the edge, nor into the mortar between bricks as this is unlikely to produce a
3 fixing.
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It is important to ensure that the facade material forms an integral part of the building structure
and is not merely cladding with little or no actual strength, as in the case of timber-framed housing or system-built structures.
Ring bolts, tie rings, etc., which rely
on an expanding wedge to secure
the anchor into a pre-drilled hole
should not be overtightened. Where
appropriate the special tool supplied by the manufacturers should
be used to fix the anchor, and the
ring bolt or other fixing inserted and
tightened by hand. Drilled in ties
should be tested before use by a
competent scaffolder. They will be
prevented from becoming
unscrewed by the tube or band
passing through the ring.
Reveal be should be attached to reveal tube
within 150 mm of end opposite to the reveal pin
whether this is horizontal or vertical
REVEAL TIE
Only right-angle couplers
shall be used (these are removed
from the sketch for clarity)
Reveal Ties
It is not always possible to provide a positive tie such as a box tie, or to drill the face of a building for screw or anchor ties. In these circumstances, a reveal tie may sometimes be used.
A reveal tie relies on a tube (the reveal tube) being wedged tightly between two opposite and
parallel faces in the building structure, such as the opposing sides of a window opening or the
he underside of a lintel and the sill. The most common device is a threaded bar and nut (called
a reveal screw pin) which can be adjusted, expanding the reveal tube assembly into the opening
and gripping it with considerable force. It is frequently necessary to use some form of packing at
end of the reveal tube to prevent damage to the building surface. A 150 mm x 150 mm piece of
plywood, 10 mm thick is usually adequate for this purpose - excessive packing should be
avoided as it may shrink and reduce the grip, causing the reveal tube to become loose.
The tie tube should be fixed to the reveal tube with a right-angle coupler, as near as possible to
the end opposite the reveal pin and in all cases within 150 mm of the face of the opening. It
should also be fixed to the scaffold in two places with right-angle couplers, as for through ties.
Every opportunity should be taken to take use the architectural features (structural not decorative) of the building to provide additional security and stability.
38
Reveal ties rely entirely on friction and should be checked at least once every seven days for
tightness, they should not be used on putlog scaffolds.
Ideally, reveal ties should not be used for more than half of the total number of ties in a scaffold.
Where this cannot be avoided, and where they are unlikely to be removed for temporary access
or any other purpose they should be spaced at least one every 22 m2. In other circumstances or
where it is not possible to provide any through or anchor ties, the scaffold should be specially
designed.
RAKERS
Where it is not possible to provide normal ties, the stability of a scaffold can be achieved by the
use of rakers. A single, unjointed raking tube, not more than 6.3 m in length may be coupled at
the top to the ledger at the second lift, extending an angle not greater than 75° to the horizontal
(4:1 ). The foot of the raking tube must be well founded and always be tied back to the main
scaffold. This arrangement can be used in place of a single tie.
NOTE Ladder omitted for clarity
Raking tube - properly founded
approx angle 4 to 1
_Base plate
~71eboard
DETAIL
Short
butt
ALTERNATIVE ON
HARD GROUND
Sole board
Base plate
39
;I
'
First Working Lift
When a working lift is required at 1.35 m as in a putlog scaffold, or at 2 m height in the case of
an independent scaffold and no firm part of the building has as yet been constructed to attach a
tie, the scaffold may be temporarily stabilised by use of rakers. When only tow ties are required
as in the case of a small house scaffold (without returns), rakers should be located, one either
end.
Rakers may also be used during the dismantling of a scaffold if it is not possible to stabilise the
structure in any other way.
TIES
Ties are essential to the stability of a scaffold. As
stated at the beginning of this chapter, the criteria governing the number and position of ties (BS
5973) distinguishes between scaffolds where a
tie is likely to be removed and scaffolds with
non-movable ties - and between sheeted and
non-sheeted scaffolds, It should be emphasised,
however, that no tie should be removed without
ensuring there are sufficient alternative ties in
place to prevent any reduction in the scaffold's
stability.
'i-ii----l!..- These Ties have
replaced the Brace.
~~~=~If.,~ they cannot be
removed.
A critical tie is a tie which has been placed in a
scaffold:
(a)
(b)
(c)
(d)
lh.f--ll-.Jii~ Critical Tie
do NOT
remove
Normal Tie
Where ledger to ledger braces have been
removed
Where a protective fan is erected
Where a cantilevered ladder stage,
loading or landing stage is erected
In the centre of a bridged scaffold
The illustration opposite shows some examples.
The scaffold was originally erected with normal
ties at points A, B and C. The cantilevered ladder
access must include a critical tie. Where the
diagonal braces have been removed, on the
fourth, sixth and seven levels, additional ties
must be added at points E and F. However,
because braces are removed from two consecutive lifts, (numbers 6 and 7), the normal tie at
point C will also be a critical tie.
Remember, ordinary ties can be repositioned. Critical ties must not be removed.
40
I
>VING AND REPLACING TIES
building a scaffold, consider the likely need for access which may involve removing and
ing ties.
1ishing and other specialist trades will probably need to gain access to parts of the build,structed by ties. It is essential to establish working procedures which are understood by
s avoids the danger posed by operatives taking matters into their own hands and removd replacing ties without supervision.
>Id ties should only be removed and replaced under the supervision of an experienced and
~tent scaffolder, who will be aware of the dangers and capable of making alternative
iements to safeguard the stability of the structure.
serious accidents have been caused by unauthorised removal or incorrect replacement of
:i.ccidents which could have been avoided by adequate supervision and the introduction of
1orking practices.
'FOLD TIES - CHECKLIST
Can the scaffold move away or toward the building?
Are all the ties fixed with load-bearing couplers?
All ties should be fixed with right angle couplers - unless ties are placed at a different
angle - when they may be fixed with swivel couplers.
Are all ties correctly positioned?
The best ties are connected to two standards, preferably braced.
If the ties are connected to ledgers the connection is best made within 300 mm of the
standards.
Are there a sufficient number of ties?
In the absence of expert advice, detailing larger spacing requirements, ties should be
fixed on alternate lifts to the full height of the scaffold and at every 6 m along its entire
length.
>al ties should not exceed 50% of the total number of ties.
Are all the critical ties intact and secure?
Remember critical ties are essential at any cantilevered point (fans, loading bays) and
where braces have been removed for access.
Remember never allow the removal of critical ties without expert advice from a
competent scaffolder.
Have any alterations been made to the scaffold?
Check items 1, 2, 3, 4 and 5 very carefully at the points where alterations have been
made.
Ensure reveal ties have been physically checked and tightened.
Ensure all anchorage points for screw or anchor ties are strong enough!
Always double check the ties after adverse weather (especially high winds).
If in doubt - seek advice from the experts.
:ING PLATFORMS
:ing platform can be anything from a minimum 600 mm platform spanning across two
restles to a cantilevered structure, 60 m up near the top of a multi-storey building.
mstruction (Health, Safety and Welfare) Regulations 1996 require that where work
· be safely done on or from the ground or from part of the building or other permanent
re there shall be provided, placed and kept in position for use and properly maintained
scaffolds, or where appropriate, leaders or other means of support, all of which shall be
int and suitable for the purpose. The provision of a scaffold and working platform is the
ommon method of meeting this requirement.
requirements relating to working platforms specify that platforms must be 'close boarded'
there should be no gaps through which men and materials could fall, and should be fitted
Jard-rails and toe-boards. They specify the width of the platform, provide for some means
'access - ladders, gangways etc., and require that precautions should be taken to
1t tools, materials, or equipment falling off, endangering those below. These requirements
strated here:
Oversail
approx
600m
Puncheon as
a handhold
~·
BOARDED LIFTS
The spacing of putlogs and transoms used to support a boarded platform is determined by the
strength and thickness of the boards used. For 38 mm boards this must not exceed 1.5 m and
for 50 m boards, not exceed 2.6 m. In practice, a standard 38 mm board, 3.9 m long must be
supported at four places.
Two boards, up to 1.8 m long,
fixed each end to a support
Fixed
Ladder access
Board, up to 2.13 m long
fixed to three supports to
prevent tipping
Four supports
The space between the edge of the working platform and the building must be as small as
possible.
Boards must rest firmly and evenly on their supports. BS 5973 states that boards should overhang their supports by not less than 50 mm and not more that 150 mm in the case of 38 mm
boards (200 mm for 50 mm boards) unless they have been secured against tipping. Short
boards tip more easily than those of a full length (3.9m). to be safe, short boards (less than 1.8
m long) should be fixed at both ends.
The platform, wherever possible, should extend at least 600 mm beyond the end of any way or
working face. This distance is known as the oversail, see sketch page 34.
Tripping hazards can be minimised by fitting bevelled pieces, or fillets, where boards overlap.
As a general rule, boards should be laid with their ends butted.
44
j
j
"'- -------------·-----
--~=
~--~
m Width
riously stated, the width of the working platform will be determined by the use for which
:form is intended.
Jm width of 600 mm - is considered adequate for access, inspection, gangways and
:Is wide - for operatives without materials, or only for the passage of materials. The
ne shows a three-boarded platform being used by a painter. Normally scaffolds are
I so that they do not foul pipes, gutters, sills, etc. An inside board can be fitted to extend
ictive width of the platform, and reduce the gap between the platform and the building.
:ts wide - gives adequate space for operatives and materials and is often erected as
:i.de platform. An inside board may be added for the same reasons as before.
:Is wide - a five board platform is commonly used by bricklayers. It is wide enough to
11aterials to be stacked on the platform and still leave enough room for the passage of
tes and materials and for operatives to work. Illustrated is a putlog scaffold: (Braces and
have been omitted for reasons of clarity.)
PAINTER
..
·'
'r::'
'
I·'
3 boards wide =
3 boards wide = Operative +
m.::itAri.::il~ -i.. n.::i~~::inA nf
i'.
6-8 boards wide - These are used by stonemasons and other who may require to dress or
shape stone or undertake other heavy work, or to support a higher platform. These wider platforms are outside the scope of this book; they should only be erected under the supervision of a
qualified scaffold design engineer.
Guard-rails and Toe-boards
Every platform where a person could fall 2 m or more must be provided with guard-rails and
toe-bards (or barriers). These legal requirements are summarised pictorially below:
Guard-rails and toe-boards may be removed for temporary access, but must be replaced as
soon as possible.
Where materials are likely to be stacked above the height of the toe-boards, a stack of bricks for
example, brick guards or other, similar barriers must be erected to prevent materials falling off,
endangering those below.
'
n
c"
"'
"00
~
2
2
2
'
~c
![
E
E oo
o•~
)
Guard-rails
~ !:2
'
Toe-boards"'-
"'
R,
'
Butt-b carded
"'A' ,~
J
I.
/
'
50mm
-
1.5 m
Max. span
--
--
--
Plan view detail A
l"1
l"I
.
I
.
'
I I
I 1
I I
.'
;
.
''
' '
I I
I I
I I
.L-L-I I
I
' I
I I
1 I
I I
I 1
l I
I
I
I
I
I I
I I
; I
; r
:
I
I
~
I
I
j
'
1~ J
i!h-
MIX
150 mm
46
!<-<> 150 mm
Min.
50mm
SS
ss to a working platform is usually by ladder. This must be secured near the top and extend
3 the level of the platform by a minimum of five rungs (1.00m) unless adequate hand-holds
rovided. The vertical distance between landings must not exceed 9 m.
must be taken to see that there is adequate space between rungs to give a firm foothold,
hat there is no possibility of the foot being trapped between a rung and a ledger, transom
ice tube.
ers are discussed in more detail in a later chapter.
anding area must be kept clear of stacked materials, etc., and be provided with guard-rails
ow-boards. The access should be as small as practically possible.
l the platform is not in use, access should be blocked off to prevent unauthorised persons,
bers of the public and children from ascending the platform and placing their lives in jeop-
Gangways and Runs
Gangways and runs should be at least 600 mm wide if used only for access, and at least three
boards wide if used for borrowing materials. Gangways, and runs should be set level if possible
but may slope up to 1:4. If the slope is more than this, stepping laths must be provided which
may incorporate a gap, not more than 100 mm wide for the barrow wheel.
Like all other platforms, where a person could fall 2 m or more, gangways and runs must be
provided with guard-rails and toe-boards.
Stepping laths
Gap for
barrow wheel
Keeping the Platform Clear
One of the greatest dangers associated with working platforms is that caused by obstructions to
free access and movement. Working platforms must be kept free from unnecessary obstructions
which can cause tripping and falling incidents.
Materials should not be stored on the working platform unless required for immediate use. They
should be evenly distributed over the entire length of the platform, and care taken to stack
heavy items as near to the standards as possible. Rubbish must be removed regularly and
trailing cables, ropes etc., clipped up out of the way. The load on the platform must never
exceed the design limits.
48
>ERS
Types of Ladder
, main types of ladder are in use throughout the construction industry; standing ladders,
::idders and extension ladders.
ling timer ladders - these are single section ladder of up to 7.30 m. The stiles are rectanthe rungs may be rectangular or round.
adder - single section ladders with the stiles made from a single pole cut lengthways, or
; of different poles of the same species of timber suitably matched. The advantage of this
·uction lies in the strength and flexibility gained by sectioning a pole lengthways. Pole
·s may be tapered or parallel. They are available in lengths up to 12 m.
Pole ladder
sion Ladders - these comprise two or sometimes three sections coupled together, which
I by sliding over or inside each other. They are very seldom used in scaffolding work.
nium Ladders - most types of ladder are available in aluminium. They are lighter to carry
mber ladders, are strong and will not warp. No ladders should be used near electrical
nent or an electrical supply because of the possibility of electric shock.
tion of Ladders
1tions require that ladders must be in good repair and strong enough for the job. They
be checked for damage, faults and wear before use. In this connection it should be noted
:Jders should not be painted or treated in such a way as to conceal defects. New ladders
' protected by a transparent coating such as a varnish, shellac or clear preservative.
Inspection of Ladders
Stiles - check stiles for warping, splintering, cracking, bruising (which admits moisture into the
timber and encourages decay). The feet of the stiles are particularly vulnerable to damage.
Rungs - rungs should not be worn or missing. Examine rungs especially at point where they
enter stiles. If they are wedged, these should be correctly positioned. Grasp the rungs firmly and
twist to make sure non rotate.
Soundness of construction - take each end of the ladder in turn and try to pull stiles apart then push together. Movement will indicate a defective ladder. A further check should be made
by laying the ladder flat, raising one end and attempting to push one stile while pulling the other.
If the stiles can be removed relative to each other in this way, the rungs are loose. Check that
metal tie rods are in place and secure and that none are missing.
Damaged or Worn Ladders
Defective ladders must be taken out of service as soon as the fault or damage is discovered.
They should be marked clearly DEFECTIVE - DO NOT USE and remain out of use until
repaired. Where it is not possible or practical to repair a ladder which is unfit for use, it should
be destroyed immediately.
--r
Carrying Ladders
Short ladders can be carried by one person either vertically against the shoulder or horizontally
across the shoulder as shown in the illustration above.
50
Long ladders should be carried horizontally on the shoulders by two people, one either end,
holding the upper stile, as illustrated, in as comfortable a manner as possible.
When carrying a ladder care should be taken in rounding corners or passing between or under
obstacles. If the ladder is being carried in an upright position, special care should be taken in
the vicinity of overhead powerlines to ensure the top of the ladder is well clear of any cable. Risk
assessment should state that ladders are never carried in an upright position in the vicinity of
power lines.
Erecting and Lowering Ladders
A ladder is erected as follows. First lay it flat on the ground with the foot towards the base of the
structure it is to be set against. One person should stand at the foot of the ladder with one foot
placed at the bottom to brace it against movement. The second person should go to the head of
the ladder and taking hold of the top rung, raise it over their head. Grasping the ladder rung by
rung they should move towards the foot, raising the ladder as they go. The anchor person
grasps the stiles as they come within reach and helps draw the ladder into the upright position.
The sequence is reversed when lowering a ladder.
One person can raise a short ladder by placing the foot of the ladder against a wall or fixture
and pushing it upright from the head.
51
Placing ladder
The angle at which a ladder is set up against a structure should be 75° or a ratio of 4 up to 1
out. The base of the ladder should rest on firm, even ground. Never pack one side of the ladder
to compensate for uneven ground either level the ground or, alternatively, bury the foot of the
ladder so that it stands evenly. On soft earth, put a board down.
The essential point is that the foot of the ladder should rest on a secure, stable base. Never
attempt to gain extra height by placing the ladder on boxes, drums or any other type of makeshift platform. If it is not long enough for the job, get a longer one!
Ladders must project at least 1.0 m above the landing place. The landing rung should be level
with or slightly above the working platform. There should be space above each rung for a proper
foothold. Ensure the foot cannot become trapped between rungs and obstructions behind the
ladder.
Where ladders are positioned on intermediate platforms these should be close boarded and
provided with toe-boards and guard-rails.
NOTE: When moving or placing ladders, beware of overhead power lines and other elec
trical hazards.
52
·,-,,
~
~I
ngs and Ties
Jer must be supported and held by the stiles, never by the rungs. It should be held
ely in position so that it cannot move from its top or bottom points,
irs provided for scaffolding access should be securely lashed from stiles to scaffold (ledger
ended transoms) using a square lashing as shown on page 43, at or just below the upper
1g. Proprietary fixings (i.e. ladder ties and clamps) may be used, but care should be taken
1 the correct type. Some require the stile cross-section to be rectangular and are not suit:ir use with pole ladders.
~r Clamp
ladders may require a lashing or tie at the mid-point to prevent excessive movement. In
circumstances the use of ladder stays will make a job both easier and safer.
1dder must not rest against (or be lashed to) any fragile surface or against fittings such as
s and drainpipes. Bracing boards should be used for windows and other openings.
po
Use of Ladders
A secure footing is essential in any ladder work and this requires sound footwear with soles in
good condition tree of mud or grease. In wet or icy weather extra care will be necessary to
maintain a secure footing.
Check there is nobody else on the ladder before climbing or descending it. Always face the
ladder and hold onto the stiles, not the rungs. Thighs and hips should be kept between the stiles
and feet should be placed in the middle of the rungs; ladders are not designed for any degree of
side loading. Do not climb higher than the third rung from the top.
Try to avoid carrying up materials and tools. If a hoist line is available, it should be used. Alternatively, tools may be carried up in pockets, on a belt designed for the purpose, or in a bag.
Whichever method is used, it should leave both hands free to hold onto the ladder.
Overreaching or stretching whilst on a ladder is extremely dangerous and can lead to loss of
balance. If the work area cannot be reached, move the ladder or obtain a longer one as appropriate.
54
mting Unauthorised Access
thorised access outside working hours can be prevented by lashing a scaffold board
s the rungs. The same precaution should be taken to prevent access to incomplete scaf~ when ladders providing access remain in position. Warning notices should also be
d in these circumstances.
ind Storage of ladders, Steps etc.
rs, especially if made of wood, should not be stored outside for long periods where the
3r can damage them. They are best stored inside, but if this is not possible they should be
,d or stored in a protected position.
'S should either be hung horizontally on a rack, supported under the stiles or rested on
, again under the stiles. They must not be supported by the rungs (this can loosen or
ise damage them) nor stored flat on the ground or against walls, radiators or hot pipes
~an lead to warping, sagging and distortion. Deposits of mud or grease should be cleaned
~s and cement wiped away before it hardens (aluminium ladders may be corroded by wet
cement). Pulleys and hinges need lubrication, cords and ropes should be checked.
mage or deterioration should be reported to the person responsible for the equipment.
MANUAL LIFTING AND HANDLING
When there is a need to manually move any object at all, reference must be made to the
Manual Handling and Work Regulations.
Of the serious accidents in the building and construction industry each year 30% involve injuries
sustained through manual lifting and handling of materials and equipment. A further 30% are
caused by slips and falls.
A scaffolder spends most of his time lifting and handling scaffolding material under a variety of
conditions. The nature of the job dictates that he must mentally alert to the inherent dangers of a
physically strenuous job. Muscles and joints can be strained by sudden and awkward movements, twisting or jerking whilst lifting or carrying a load, or by attempting to lift too heavy a load.
Back injuries are common. They may be the cumulative effect of repeated minor injuries or the
result of abrupt strain.
The risk of injury can be reduced by adopting a correct mental attitude, which encourages good
lifting techniques. Stoop lifting should be avoided; it greatly increases the chance of back injury.
The stress imposed on a rounded back is much greater than if the trunk is kept upright, using
the leg and thigh muscles to power the lift.
The illustration shows an example of stoop lifting. The trunk is twisted to enable the hand to
reach down to the load, which is grasped by the finger-tips, and the knees have been locked to
prevent the man overbalancing. The muscles in the lower back are about to do the work and will
come under great strain as the worker attempts to simultaneously straighten up and lift the load.
The consequence of this may be a slipped disc or tom back muscles.
THIS DIAGRAM DEPICTS
DANGEROUS PRACTICE
Kinetic Lifting
The kinetic method of lifting enables the worker to make full use of the body's own weight and
momentum to initiate the lift. The nature shape of the spine is maintained throughout (although
the body may be bent forward the spine should remain straight) and the lift is powered by the
strong leg and thigh muscles. This method of lifting involves the minimum amount of muscular
effort and reduces stress and fatigue.
56
>llowing six key factors should be practiced until they become second nature, a single
Jinated action.
Feet - All lifting and handling can only be
ssful if it is carried out on a firm base. The
Ider may work from the ground, or on a
1rary platform and it is essential that the feet
3.ced so that a good balance is maintained
1hout the lift.
is no correct or exact distance apart for the
:ach individual has to consider his own
t, height and build. In general terms the feet
! be in line with the lift, comfortably apart,
ne foot slightly in front of the other. The rear
1ould point forward when lifting, in the
on of movement. This position gives a
adaptable balance and a wide enough
o perform the lift.
Legs Having established a good base for the lift and recognised that it may be necessary
•e adjustments of balance, it naturally follows that the legs must be relaxed sufficiently to
e flexibility. To obtain flexibility, both knees must be unlocked to allow the feet to adjust
atically. This is a requirement for all good movement.
it is impotent to unlock and bend the knees, they should not be placed into the complete
:iosition as this will place extreme pressure on knee joints. The illustration shows the
d leg at 90° angle whilst the back leg will provide the thrust for the lift. Although the lifter is
iing one hand, the weight will be taken through the centre line of the body, thus maximis' use of body weight.
i'
3.
Head The head should be gently raised and the chin tucked firmly in. This will not only
straighten the neck; but the whole spine and it will bring about many other corrections in body
movement, automatically lifting the chest and preparing the arms for a more efficient action.
This head action should be carried out at the initial stage of all lifting movements.
4.
Straight Back A bent back is a
weak back. It will lead to excessive muscular tension and damage to the spine. It
will also undermine shoulder and arm
efficiency. Generally, if the correct head
position is adopted, the back can be kept
straight, even if it is not vertical.
The back should straighten automatically,
prior to the hands taking the load. The
illustration shows a difficult lift; the feet are
well planted, the knees well positioned
and the back straightened as the chin is
being drawn in.
I
j
1
5.
Arms Arms should be a close to the body as possible. The further the arms are extended
the greater the strain. The elbows should be kept into the body.
6.
Grip A good grip is essential for the scaffolder as he spends the majority of his time
handling tube which because of its shape, is difficult to grasp. Whenever possible, one hand
should be below the load, with most of the weight being taken by the palm and roots of the
fingers.
58
~
- ·-----
·~-.::_-
__ _,_~----'~--~~: ~
ence of Lifting a Scaffold Tube
~ lifting any weight, a worker must ensure that the ground area is clear and free from
1g hazards. It is important to see that no-one is in the way and that there is nothing likely to
1ct the lift. The weight should be within the lifting capacity of the individual worker. The
;hould be approached squarely, facing in the direction of travel. The feet must be placed
with one foot slightly in front of the other to maintain a comfortable balance, the knees
md the body as close to the load as possible.
Jbe should be firmly grasped, with the arms kept as close in to the body as possible,
ing the tube in front of the body. Adjust the position of the head (head up - chin in) and
to lift using the leg and thigh muscles. As the tube is raised transfer the grip to maintain a
ced grasp on the tube, holding it close to the body.
reight of the body can be easily
erred from one foot to another,
ing that the balance is maintained
nabling the load to be taken by the
1 body.
1se of the bodyweight if best illuswhen the scaffolder is carrying long
in the vertical position. The diagram
;ite shows the back leg still in the
· position, the front foot in the direcf the lift. The back is straight and
erect.
1
veight is taken on the palms of the
; and the entire bodyweight is posij to resist any movement of the tube.
that the top forefinger is extended
the tube and will act as a sensor to
iarly warning of any movement of
1be, enabling the feet to be reposij to maintain a good balance.
~mber!
sand pains are warning signals and indicate fatigue and stress. If ignored, the final
1me may well be some form of injury as a result of incorrect lifting techniques.
LIFTING SCAFFOLD TUBES
The following sequences show some of the common handling and lifting tasks required of scaffolders every day.
Safety Check
Before lifting, check (a)
that the area is clear of any tripping hazards
(b)
that your action will not endanger anybody
(c)
that you are capable of lifting the load
Lifting a Long Tubes
The correct foot position has been adopted
- front foot in the direction of the lift, the
rear foot ready to thrust behind the load.
The chin is still to be tucked in, but the
back is straight.
The tube is lifted - the feet have been
adjusted to allow the lifter to walk to
the canter of the tube using a hand
over hand movement to maintain the
weight of the load. The chin has been
tucked in thus maintaining a straight
back.
60
g reached the centre of the tube the
; adjust for balance. The hand which
;ed over the tube is bearing very little
t because the hand under the tube is
med closer to the centre of the tube
therefore taking most of the load.
ie tube is ready to be raised to the
ig position which in this case is on
oulder.
lift is carried out it will be necessary
body to be turned in the direction of
ended line of carry.
ees are unlocked and ready to
ie feet to adjust to the new position.
TIS and shoulders are used to begin
,·
~
\
.,.'
--
- -·
-"-= - ---"-~
------·- '"-''--'---" -
--____:. __ ,
As the lift nears the correct height the feet
have begun the adjustment which will
allow the body to turn under the tube and
allow the shoulder to receive the weight.
The load has been released by the load
bearing hand and transferred to the shoulder, the other hand is kept in position to
steady the tube. The feet have nearly
completed the adjustments.
The shoulder hand has been placed into
the steadying position, the feet have
completed the adjustments and so
allowed the body to complete the turn
safely.
The lift is complete, and the carry can
begin.
'
To place the tube back on the ground, the
actions are reversed.
62
:> TUBE (Vertical Carry)
1
before performing the lift (a)
Ensure the area is clear of tripping hazards
(b)
Ensure your lift action will not endanger anyone
(c)
Ensure you are capable of handling the load
u are about to carry the tube in the vertical position
(d)
Ensure the area and space above head height is clear along the entire length of
the carry
(e)
Ensure there are no overhead cables in the vicinity
ame actions as in the previous lift are carried out, until the load is taken by the hands in
'ntre. The end of the tube should be butted against something solid. If nothing is available,
er man can use the instep of his boot to block the end of the tube.
·-·--:
Note: Never use the toe of the boot as
the tube could twist out on eitherside
and cause a very painful injury
-I/
Having butted the tube it can be raised
above the head and with the bodyweight
behind the tube, and the palms and heels of
the hands bearing the weight, the tube can
be walked to a near upright position.
)-_
.
..---
The tube is now ready to be lifted, with the
knees unlocked, the back straight and the
chin tucked in, the bodyweight is positioned
to resist the movement of the tube.
NOTE: The high hand forefinger is again
acting as a sensor
To begin the lift, the knees bend and both
hands maintain the same distance apart by
sliding down the tube equally. This will
incline the tube even more towards the
lifter, who accommodates the movement by
slightly bending the high arm which is the
arm that is about to take the entire load the bottom hand is only acting as a guide
and restraint.
64
't is completed as the legs straighten.
must remain unlocked allowing the feet to
the necessary adjustments which will
I the body to change to the direction of
1e manoeuvre completed the carry can
: the bottom hand is placed round the
9 of the tube to act as a restraint, whilst
> hand bears the full weight of the tube
I
I
I
I
------
1 Short Tubes
1ethod is normally used when lifting short tubes (between 1 .5 m and 2.4 m) which are
l at ground level.
ature position is adopted for selec1tube.
i initial selection is made by inserte fingers into the ends of the tubes,
:;sential to ensure they are free of
edges.
tubes are now upright and can be
sted to form a pyramid pattern with
Jase toward the shoulder.
knees have remained unlocked; back
ill straight. The feet have made the
issary adjustments. Chin remains
y tucked in. The bodyweight is still
nd the load.
As soon as they are clear of the ground
the free hand is placed under the tubes to
assist in control.
NOTE: Three tubes have been raised
although the third one is hidden by the
other two.
-~
i
p and bottom hands slide down the tubes
knees bend. This will allow the shoulder
1ositioned just below the centre of the
iight is taken on the shoulder
3 forward hand and shoulder
ting as a restraint.
The rear foot is in the thrust
i and the bodyweight is posiJehind the load.
shoulder is below the centre
•the load it will easily tip over
horizontal position, with the
ind steadying the momentum.
Jbes reach the horizontal
the legs carry out and com) lift.
lift completed the carry can
· the tubes back on the ground the movements are repeated in reverse.
The illustrations have shown a man lifting tubes at ground level. It can be clearly seen that the
job is physically strenuous. Scaffold tubes are unwieldy and difficult to handle. The problem is
even more difficult when tubes are handled vertically.
The scaffolder has to use the same handling skills when working on a three or four board wide
platform a considerable height above the ground. Apart from using the correct techniques a
scaffolder must be even more careful in making the usual pre-lift checks when handling long
tubes vertically.
The final illustrations show some of the dangers which may be encountered.
THIS DIAGRAM DEPICTS
DANGEROUS PRACTICE
~~===
Winds - Which
can be sleady or
gusty
Electricity or telephone cables
Open windows
Ornate sills
Tube end should
be good and
sleeve or spigol
serviceable
Inadequate
temporary
platform
Some hazards which might be encountered
68
~S, KNOTS AND HITCHES
orrect use of rope and knots is very important in scaffolding work. Ropes are used for
J and lowering tubes, boards and fittings, and lashing ladders and boards.
~of Rope
' can be broadly split into natural fibre and man-made fibre ropes.
Natural Fibre
Manila
Sisal
Hemp
Cotton
Coir
Man-made fibre
Polyamid (nylon)
Polyester
Polyethylene
Polypropylene
larger than 8 mm in diameter are generally supplied in 220 m lengths.
>St common size of rope used for lifting materials in scaffolding is 18 mm diameter. This
orrect size for the use with a gin wheel. Smaller wire ropes are used for lashing ladders.
are classified by the number of strands and the manner in which the strands are twisted
ited together. The only type in common use is the three stand plain (or Hawser laid)
de fibre ropes are gradually replacing natural fibre ropes. The reasons for this are that
stronger, less liable to chemical attack, completely resistant to mildew and rot and have
iter resistance. However, they do burn and care should be taken to avoid excessive
1 shears and blocks where care must also be taken to see that the correct size of rope
st also be taken when oxy-acetylene cutters or blowlamps are in use. The flame must
lowed to come into contact with any man-made or natural fibre rope.
the most suitable ropes for use in scaffolding are of staple spun or fibre film polypropylse are not as strong as nylon and polyester but are considerably cheaper. They are
ible and cheaper than manila; are particularly water resistant and float in water. The
1-back of this type of material is that as temperature increases it becomes softer and
1ngth; however, this only becomes sinnifir.,,nt "h'"'" i:;nol"' , .. h~-~ ..... _ .• _ '- - '·
---------------.----~~.--~·--.....
Care and use of Fibre Ropes
Fibre rope, like wire rope, can be damaged while it is being removed from the shipping coil. A
new coil or rope, should be laid flat on the floor and unwound through the coil in a counter-clockwise direction. Even when the rope is unwound correctly, loops and kinks may form and
these must be carefully removed, to avoid damage to the rope.
in
an
After use, the rope should be re-coiled in a clockwise direction. When coiling the rope remove
kinks as they form.
If t
lo
to
da
Storage
w
Poor storage can cause fibre rope to deteriorate as rapidly as harsh use. In order to keep ropes
in good condition for as long as possible.
*
Store them in a dry cool room that has good air circulation
*
Do not store ropes on the floor, in boxes, or in cupboards where the air
circulation is restricted. They should be hung up in loose coils on large
diameter wooden pegs well above the floor
Protect ropes from wet weather and sunlight. They should be kept away from
boilers, radiators, steam pipes and other sources of heat and all exhaust gases
Dry and clean wet ropes before storing them. Moisture not only hastens decay
but also causes the rope to kink very easily. It a wet rope becomes frozen,
it must not be disturbed until it is completely thawed, otherwise the frozen
fibres will break when handled. Allow wet and frozen rope to dry naturally.
Too much heat will cause the fibres to become brittle and the rope will be
unfit for further service.
so
K
*
*
rel
c
T
R
T
Use of Ropes
,_,
'
*
Never overload a rope
*
Never drag a rope along the ground. The outside will be damaged and grit will become
embedded and destroy the internal fibres
*
Never drag a rope over sharp or rough edges and never drag one part of a rope over
another
*
Avoid all but straight line pulls with rope; a knot or bend will weaken it by approximately
50%
*
Pack all sharp corners when lifting materials, to prevent them abrading the rope
*
When a wire rope is attached to a hook or ring a thimble should be placed in the loop or
eye to reduce the wear on the rope
*
Never use fibre rope near welding or flame cutting operations. The sparks and molten
metal can damage the rope or set it on fire. Avoid exposure to all forms of heat
70
!ction
inly way to determine the safety of a rope, and its load-carrying ability is by regularly
cting every metre of its length. The main points to be watched for are external wear, cuts
.brasions, internal wear between the strands and deterioration of the fibres.
rope is dirty and in poor condition, or if the strands have begun to unlay, or if the rope has
> life and elasticity, it should not be used for lifting purposes. Should there be any doubt as
ether or not a rope is fit for use, it should be replaced at once. Never risk danger to life or
ge to property by taking chances.
a rope has been condemned, it should be destroyed at once or cut up into short lengths
.t it cannot be used for lifting purposes.
·s, BENDS AND HITCHES
and bends cut the rope strength by 50% and hitches reduce the strength by 25%. This
; to the final strength of the rope and not the resistance of any given knot to slip.
1on Knots
ost common knots and hitches used in scaffolding are:
g Hitch
the preferred knot for lifting tubes and boards
of Eight Knot
o lock a rope in position i.e. to prevent it sliding through a block or to temporarily prevent
:l of the rope from fraying
1
Rolling Hitch
Figure of Eight Knot
Timber Hitch
Suitable for lifting boards, sometimes
used in conjunction with a half-hitch.
Square Lashing
Used in scaffolding to secure ladders
to the scaffold structure. Begin the
lashing with a clove hitch and pass the
rope over and behind the transom or
ledger and back in front of the ladder
stile four times. Make two trapping
turns and finish off with another clove
hitch. Lash both stiles.
T
Timber Hitch
Square Lashing
72
w
~G AND LOWERING MATERIALS
affold gang spends a great deal of its time during the erection and dismantling of scafraising or lowering tubes, boards and fittings. This work has to be carried out in all kinds
ther, and at many different locations - in the High Street or other public places, on
3d building sites or on some major civil engineering construction in a remote area. The
Js used to raise and lower scaffolding materials will be determined by the extent and type
fold being built and the equipment available.
1
3thods available will generally fall into one or other of the following categories:
Handballing/chaining
Light line/hand line
Forklift truck
Goods hoist
Gin wheel and rope
Tower Crane
iapter examines these various methods and suggests how risks can be reduced and
g efficiency improved.
1alling, sometimes called chaining, is the method normally adopted on the first few lifts of
old. The gang will form a chain up the face of the scaffold and pass tubes and boards
1e to another. The illustration shows a good example of handballing. Note operatives
rear safety harness during this operation.
c
a
I
!
A
has passed a long tube to man B who, like man C, has adopted a good safe position
he can use both hands to raise the tube. Man A should not release the tube until man B
'!!Arh1 inrli,...a+arl ha hac- f1111 f"'r'\nt.-nl l"\f +ha +11ha
fl nnnrl mothnrl nf f'nmm11nir!'.:ltinn i~ fnr thA
-
-
'--
-
-
-
I
_ .. _ _ c.~-
I
I
\
Light line, sometimes called a hand line, is often used on scaffolds up to 15 m high. Tubes,
boards or sacks of fittings are tied to the lower end of a 13 mm fibre rope and then hauled up by
hand. It is essential to adopt a safe position when doing this. This involves using a standard for
support, one leg being placed behind the standard to act as an anchor and prevent the lifter
T
1
h
w
T
d
in
from overbalancing.
Body
positioned
behind
standard
Back
straight
Knee
slightly
bent
Back tends
to bend
Crouch
position
Leg
placed
behind &
either side
of
standard
I
Feet
planted
firmly
on
ledger
Foot
position
wide
CANNOT OVERBALANCE
STANDARD ACTS AS
AN ANCHOR
I
,
____.,... Rope attached
,,.,....-in wrong place
DANGEROUS PRACTICE
COULD OVERBALANCE
NO FAIL-SAFE BACKUP
74
lin Wheel and Rope is commonly used to raise materials, which are tied to the end of a
n diameter rope passed over a single wheel pulley. The gin wheel (pulley) is fixed to a
>ntal cantilevered tube. The material is then hauled up by the man on the ground to the
ig level.
vpes of gin wheel are available, the 'Ring' type and the 'Hook' type. The ring type is
ied to fit over a scaffold tube. The hook type only differs at the point of suspension;
.d of a ring the pulley is suspended by a hook.
750mm
The gin wheel is usually suspended from
a cantilevered tube. This should be properly fixed with right angle couplers, preferably to two standards, approximately 2 m
above the landing place. If the cantilevered part of the tube is unsupported, the
point of suspension should not extend
more than 750 mm. Check fittings should
be fixed either side of the suspension
point to ensure the gin wheel cannot
move. If a hook type wheel is used it must
be suspended on a 6 mm wire lashing
with at least five turns around the hook
and tube and the open end of the hook
must be moused to ensure it cannot be
displaced.
The fibre rope should have a minimum
diamer of 18 mm and a stopper knot
(usually a figure of eight knot) tied near
the ends so that it cannot run through the
.... ; .... ... i-. .......... 1
!·
750mrn
F
f
al
lo
w
co
is
Ex
COi
G
th
(tr
Re
low
The maximum load that should be raised or lowered by a gin wheel and rope at any one time is;
50 kg. The load imposed on the scaffold will be double that being lifted. Make reference to
!.
Manual Handling an Work Regulations.
,.
!
Care should be taken particularly when lowering materials. If the weight is too great either the
man lowering the load will weigh less than the load and will be pulled off his feet; or the com- 1
plete assembly may collapse.
'
---~---
"
----
----
ft Trucks are frequently used to raise and lower scaffold material to and from the scaf
It is essential that the fork-lift driver is made aware of the weight of the load. He should
ow the load bearing capacity of the scaffold. Working platforms are sometimes over
by enthusiastic operators who are not aware of these factors.
a fork-lift truck is used for loading a platform, a second front ledger is sometimes fitted, in
and below the main front ledger to provide extra protection from impact and as a check
Cranes are often used to raise and lower large loads of scaffolding material, during the
~tion of multi-storey blocks. The driver should be made aware of the weights involved; it
itial to ensure that the scaffold is capable of bearing the load.
i care should be taken by the man receiving the load. The crane driver has only a limited
rnd the receiver can be easily knocked from the platform.
Hoists should only be used to raise or lower material that can be safely contained within
of the hoist platform. This rule generally restricts the scaffolder to very short tubes,
is) and scaffold fittings.
ber many accidents are caused by falling materials. Ensure that all material is raised,
and placed safely and securely on the platform.
1.:
Organisation and Working Methods
T
Erecting a scaffold involves a great deal of hard physical effort - it is hard work, generally only
undertaken by fit young men. As with all work of this kind there is no absolutely right, or correct
way of doing the job - much will depend on the particular circumstances; the height and extent
of the structure, the nature and location of the site, the numbers employed and so on. It remains
true, however, that unless some thought is given to planning and preparing for the job a great
deal of time and effort can be wasted.
Wasted effort means unnecessary expense, tired operatives, (who are likely to cut corners or
make mistakes), and sub-standard work. The result may be an increased risk of accidents to all
those using the scaffold and even to innocent passers-by.
Ea
Example 1A
A gang of scaffolders arrive at a site to erect an independent scaffold, 36 m long by 25 m high.
They have a choice of unloading at points. A, B or C. They choose C, unload the lorry and
begin laying out material from point A and working back towards the unloading point.
At
mu
/.l'//.t"..I'/
(N
sta
BUILDING LINE
SCAFFOLD POSITION 36rn LONG ------~
A
Ex
B
Material
Stack
The material has to be carried and laid out for each of the lifts.
Each 6 m section of the 36 m run contains:
2-6.5 m ledgers
2-2.5 m braces
6-1.8 m transoms
26-scaffold fittings
Eag
Each lift of scaffold requires one person to carry and lay out these materials six times.
78
distr
'{_'.!_.
ii distance walked is as follows
~F~-<---~----'--~--'-B--.,r--__,_----,--~--.~--;;C
Total 36m
12 trips x 9m =Total 108m
12 trips x 15m = Total 180m . - - - - - - - .
12 trips x 21m =Total 252m
Material
12 trips x 27m = Total 324m
Stack
6 rips to and 6 trips from = 12 trips of 33m each trip = 396m
J comprises one carry and one return trip, so that each 6 m run requires
2 trips of 33 m which equals 396 m
2 trips of 27 m which equals 324 m
2 trips of 21 m which equals 22 m
12 trips of 15 m which equals 180 m
12 trips of 9 m which equals 108 m
12 trips of 3 m which equals 36 m
f 1296 m per lift, to be walked by one man. As there are 13 lifts to be laid out, one man
.lk 16848 m (13 x 1296), which is the equivalent of 101/2 miles.
e above calculations do not include sway braces, boards, guard-rails, toe-boards,
Is, ladders or ties).
e 1 B The material is unloaded at point B
-F
L
B
c
Material
Stack
12x3m=26m
12 x 9m = 108m
12x15m=180m
~
36
-1'»-~--
108 -~
180
n section would require the same number of trips (i.e 12) but as the materials are
~d from the centre, each 36 m run will require:
~ trips of 15 m which equals 180 m
~ trips of 9 m which equals 108 m
~trips of 3 m which equals 36 m
12 trips of 15 m which equals 180 m
12 trips of 9 m which equals 108 m
12 trips of 3 m which equals 36 m
f 648 m per lift, to be walked by one man. Again 648 m multiplied by 13 lifts equals
Nhich is nearly 8.5 km.
Comparison
!
The distance between the two positions Band C is only 18 m, but through lack of foresight, over 1I
10 tonnes of material has been carried an additional 8 km. Expressed more simply, by thinking
ahead and planning where the materials should be unloaded (and before that, at the Depot, of
how they should first be loaded into the lorry), the effort, time and cost of laying out the materials can be considerably reduced, as can the risk of tired men taking mistakes and causing
accidents.
To achieve a planned and organised work pattern it is necessary to examine existing methods
of work. Each task should be analysed:
(a) What can I do to improve the flow of work?
(b) What can go wrong?
If question (a) had been applied to the first example, a considerable amount of time and effort
would not have been wasted. Question (b) is necessary when planning a work pattern to identify
potential hazards. The next example shows how these questions give results that improve
productivity and decrease the risks.
Example2
One further example will serve to show how a thoughtful, common-sense approach to the job
can save time and effort to reduce the risk of accidents.
In the sketch below three men are employed in erecting an independent scaffold.
DANGEROUS PRACTICE
•.
)(
®
Man A is fixing right angle couplers to standards, ready to receive ledgers.
Man B is throwing up fittings, dragging the sack of fittings along behind him.
Man C is catching the fittings and placing them on the platform, ready for Man A.
80
A more efficient use of labour is achieved in the example shown below.
·er
g
©
0
ify
®
Each of the men on the platform has his own sack of fittings, which has been raised to the
working level with the aid of a light line. The third man (B) can be employed laying out ledgers
ready for fixing. This is obviously a more productive arrangement. Two men are employed in
fixing the couplers instead of one, as in the original example, with the third man preparing for
the third man preparing for the next stage of the work. The job proceed more quickly and the
risk of someone being injured by a badly thrown or misdirected fitting is eliminated.
Safety Note
The common practice of throwing up fittings is efficient only where a small number is required
and the distance thrown is not too great. The risk assessment should always be referred to
before throwing up fittings. It is far safer to place the fittings in a sack and haul them up to the
required level with a line and gin wheel.
It is not intended to condemn this widespread practice outright; there will be occasions where it
is an quick and easy to throw up a few fittings as it is to rig up a gin wheel and line - but it should
never be done:
(a)
if the scaffold is being erected in a public place
(b)
near glass or near a fragile roof
(c)
anywhere it may cause injury to a third party, or damage to property
(d)
anywhere other than from ground level
(e)
if the practice contravenes the company's Safety Policy
81
__ :c; ---
~-·
>afety and Efficiency
·hese are only two examples of how, with forethought and planning, and by adopting an intelli1ent approach to the job, scaffolding work can be made easier, less costly and safer. There are
nany opportunities in scaffolding work to practice these principles. What is needed above all is
l thoughtful, conscientious attitude to the job and a concern for safety.
\s in so many instances involving scaffolding work, efficiency and safety go hand in hand;
ifficient working methods are usually also the safe way of working.
Bridging over a garage roof: can the roof take the weight?
D
Resting on windowledge - tied if possible
D
D
LJ.
Some weight taken to
window ledge BUT can
garage roof take the rest?
Helps to stop scaffolding
sliding down roof
NOTE: FRONT SCAFFOLD OMITTED FOR CLARITY
A lightweight bridge over the garage.
Reveal Tie
~
er==
\
~
'-
\
.
I~
I
I•
A
.
'#
~~
'
Protection
over Doorway
/~II
#.
'
-
=
"
-----
vi
!
!
-
'
lj
'
........ __
.._ ..... '·-
·- --
GARAGE
~
I
Spur
Raker
both taking
weight of bridge
NOTE: BRACES, BOARDS, etc., OMITTED FOR CLARITY
84
7
rangement for re-rooting that will reduce the amount of wear and tear on the garden and
so increase productivity.
Main access Scaffold
Walkway
TERRACE
OF
COTTAGES
r-
NOTE: LADDER ACCESS & END TABORET OMITTED FOR CLARITY
: TERRACE OF COTTAGES
'
I
1
~
P====~r::J=====~liooli=====~~o
Cottage 1
Pathway
Cottage 2
·f-·-
1----
II
Baseplates nailed
to So\eplate
Standards approx
150mm apart.
A typical arrangement on a shop front. The
inside standard is founded at the first floor
level and the outer standard on the pavement. Generally these scaffolds are for
decorators. Occasionally a fan will be added
to the scaffold when roofing or chimney
work has to be carried out. It may then be
necessary to double the outer standards as
shown.
Shop
Name
L-1--i/&'~ Sign.
Normally
4.2 M
Brace to
stiffen &
strengthen
Standards
'-shop
Doorway
The same principles can be applied to the base of a house with a basement floor.
Reference to the chapter on Foundations will show other typical obstacles that face scaffolders-
86
- .L~~':·eo _-"''"-'~---
- -
LIC HAZARDS
ment scaffolds cause many problems for the scaffold gang. Materials have to be unloaded
1tacked on the pavement or in the gutter, presenting an obstacle and a hazard to others. All
authorities have rules and regulations that must be observed; for example a pavement
:e may be required. It may also be necessary to seek permission from the police to unload
> in 'No Parking' areas. Risk assessment must be completed to identify possible hazards.
1ever a scaffold is erected in a busy public place it is recommended that the local police
ipt informed. They can give valuable advice and help in solving many of the problems that
trise.
Between 2.1 & 2.5 m
Lift height
Spare material &
ladder stowed on
bottom lift overnight
Nothing projecting
over or into the
roadway
Bottom lift should
be close-boarded
Ledger braces
removed for access
after ties have been
fixed
"\\,,
\\
\\
\\
Tubes painted
white or
adhesive
fluorescent
stripes
,,
\\
' \\
\\
\\
,,\\
,,
\\
ii,,
Plastic protective cup
inserted into or over
the end of tube
in gutter during erection
(with warning cones)
All joints should
be wrapped to protect
public from sharp edges
Ii
fl
I
,,11
The first duty of a scaffold gang is the protection and safety of the public. Particular problems
will depend on the location of the scaffold; it may be in a busy shopping area, with a narrow
pavement adjacent to traffic lights, or near a school, a park or playing area, or public house or
fish and chip shop. Whatever the location the following problems will need to be considered:
I
At busy and congested sites a very early start will enable the gang to unload the lorry and erect'
the base of the scaffold before the traffic builds up.
:
It may be necessary to remove ledger braces to permit access under the scaffold, and provide '
close-boarded bottom lift to stop anything falling onto pedestrians. If guard-rails or foot tie
ledgers are provided, the ends of the tubes should be capped and all joints should be wrapped
to prevent injury to passersby.
Children are inquisitive and fearless. They will climb ladders or even shin up standards, and
have a habit of getting themselves into danger. A special watch should be kept when children
are out and about after school. Always attach a scaffold board flat against the rungs of the
ladder when leaving the job for lunch or tea breaks to prevent unauthorised access.
The evening and night-time can bring problems from older children, vandals or adult revellers ..
All spare material should be secured, either by removing it from the site or stacking it securely
on the first lift. Always remove ladders and put in a safe place - out of reach.
If through ties have been fixed, someone should ensure that the open window cannot be use
by an intruder.
88
:RAL SAFETY CONSIDERATIONS
Safe passage must be provided for the public. Remember blind people, wheelchair
users, senior citizens, people with shopping trolleys, prams, pushchairs etc. may have
difficulty in negotiating places where access is restricted. Barriers should be erected as
required.
No part of the scaffold must project into the roadway where it may be struck by any
vehicle
Statutory requirements, local authority regulations and police advice should be complied
with
Lighting regulations must be observed
Safety notices to be displayed as necessary
· Safety Considerations
Projections such as canopies, large coping stones, bow windows, drain-pipes, etc.
Overhead electricity and phone cables
Fire escapes, emergency exits etc.
Foundations
iderations Prior to Dismantling
Are all the ties intact and secure?
Have any adoptions taken place, and if so, have they affected the stability of the scat
fold?
Has the scaffold been damaged?
If the lighting is fixed to the scaffold, has it been disconnected from the power supply?
PROTECTIVE FANS
Fans are erected to afford protection from anything which may fall from a scaffold or a building.
They comprise an inclined framework of scaffold tubes covered with scaffold boards. The
diagram below illustrates the general arrangement.
CRADLE
WINDOW
TRANSOMS
PAVEMENT
ROAD
Fans are not intended for access to a scaffold, nor for the storage of materials. Warning notices
to this effect should be clearly displayed on the fan.
FANS ARE FOR PROTECTION ONLY
DO NOT USE FOR ACCESS OR
STACKING
Types of Fans
Fans are classified lightweight or heavyweight according to their load capability. It is not always
possible to predict what weight will fall and from what height.
Class A:
A light duty fan with a maximum loading equivalent to 0.75 KN/m2, suitable for
protection from paint and mortar droppings.
90
;B
A medium duty fan with a maximum loading equivalent to 1 KN/m2, for protection
from bricks, aggregates and like weights from heights not exceeding 1O m.
;C
A fan with a loading over 1 KN/m2, which should be designed to suit the
application.
;D
A fan for arresting the fall of persons or like weights from a height of 6 m or two
storeys. This is a safety net system and should be in accordance with BS 3913
and rigged in accordance with CP 93.
1n and Construction
in class A and class B may be specifically designed although the standard form will be
ructed without design drawings. Class C and D fans must be professionally designed and
3yond the scope of this book.
Attached to Scaffolds
consist of outriggers or needles extended from the scaffold, supported by wires or spurs
·s). Transoms are run parallel with the scaffold ledgers to permit the fan to be boarded or
ed at right angles to the buildings or scaffold. A common method of fixing light duty fans is
;s the outriggers over the outside ledger and under the inside one. The problems of this
Jement are shown on the illustration. In any case, it is better not to fix fans to existing lift
rs.
jditional loading on inside ledger
ight cause uplift- although unlikely.
3._ __,,
kelihood of materials being placed
1 fan. Difficulty of removing debris
a working lift.
2
'ire support can cause falling mate
tis to bounce off and miss the fan.
ire may also be damaged.
iallow angle allows falling material
build up on outside edge of fan.
3moval of this poses safety hazard
people on fan.
mdrails erected on outside edge
fan encourage personnel to walk
1 fan and increase fan loading.
4
1
5
Fans Attached to Buildings (Class A)
These are generally used in conjunction with cradles for window cleaning, stone cleaning operations or other maintenance work on the face of the building. The suspension points for the
cradle and wire for supports may often be the same. Large quantities of water are often required
for these jobs. In these circumstances corrugated iron sheets must be fixed so as to afford
adequate and safe drainage.
Detail of
\
General Construction Requirements
Outriggers (needles) should be spaced every 1.5 m for fans attached to buildings, and every
bay when attached to scaffolds. Class B fans should be fixed at every scaffold bay.
Support Transoms must be spaced so as to make sure there are no 'traps' in the decking.
Parapets should be erected by fixing puncheons on the outside fan ledger and fixing toe-boards to these.
Spurs and Rakers and generally described as transom supports if used to support the fan from
above instead of wires. The term spurs is generally used to describe raking tubes used to
support the fan from below. Spurs should be fixed to the outside fan ledger or an additional
ledger within the outside third of the fan.
Wires the diameter and strength of suspension wires should be designed according to the size
an loading of the fan. Most purpose-made slinging wire is 8 mm independent wire rope core
(IWRC), which has a breaking strain of 4 tonnes; but a safe working load of 0.5 tonnes. Wires
should be fixed using a round turn and two bulldog grips. ON NO ACCOUNT SHOULD 6 mm
DIAMETER WIRE LASHINGS BE USED.
Additional Ties must be fixed at the level of the fan (see chapter on Ties); only load-bearing
fittings may be used in their construction. Large fans supported by spurs will require additional
bracing.
92
[ing
1 erecting a fan it is important to make sure that the lift at the level at which the fan is fixed
~rded out, so that material does not fall down the inside of the scaffold. Alternative arranges may be made, for example, parapets fixed to the inside of the fan, or the next lift down
led out.
old boards should either be lashed, using 6 mm wire, or secured with an additional scaffold
Galvanised corrugated iron sheets may also be fixed using tubes or with a variety of
.ing clips round the edge of the sheets, or with sheeting hooks which pass through the
s and hook round the supporting scaffold tubes.
are often exposed to high winds with the potential to lift sheets and boards off the fan;
iquently it is important to make sure that all decking is firmly secured.
---- _,_ ___:.-----=
>AFETY CHECK
Spacing of outriggers to suit load on fan, i.e. type of decking and duty of fan
Scaffold must be:
- close boarded
- properly lashed or held down
- properly supported, i.e. no traps
*
Corrugated iron sheeting must:
-have a minimum of four clips or hook bolts per sheet
- drain properly. Guttering and drain pipes must be fixed where necessary.
Fan should be inspected by the user and particular care taken after high winds and
*
storms. Any damage to the fan must be repaired immediately.
'{,
94
Part 2
Basic Scaffold Structures
I
I ~
i
endent Tied Scaffolds
dependent tied scaffold is perhaps the most commonly used scaffold. It consists of two
1f standards parallel to the building, joined together with ledgers fixed with right angle
1rs. In turn transoms are fixed at right angles to the ledgers with putlog couplers. The
1bly must be braced with ledger bracing, usually at alternate pairs of standards and with
1dinal or facade bracing every 30 m along the face of the scaffold. Independent scaffolds
1e tied to the building.
Transoms
Joint pin
......
Ledger
to ledger
brace
Swivel coupler
\,,,..,....,...,
Facade brace
md loadings
es to which independent scafiay be put and their associated
sible loadings are summarised
i973 Table 1 (see page 12).
Foot tie
Sole board
idependent scaffolds are five boards wide with four boards between the standards and
ard between the inside standard and the building. Two and three board scaffolds are
rhAn thArA ic:: ri::i.c:::.trif'tArf !:lf"f"t:::ICC hot\A1oon h1 iilrfinnc nr fnr incnof"'tinn n11rnncoc nnh1 Inna._
The requirements for bracing and tying independent scaffolds have been discussed in other
chapters; however, these are summarised below for convenience.
Longitudinal bracing every 30 m along scaffold, either continuous or 'dog-leg'
*
*
*
Ledger bracing at alternate pairs of standards, using right angle couplers from ledger to !
i
ledger or swivel couplers to standards
I
Ties should be every other lift and approximately every 6 m along the scaffold. Not morel
than half of the ties should be reveal ties.
ACCESS
The main working platform for independent scaffolds can often be 30 m - 40 m above the
ground. Consequently, access of men and materials to this platform requires careful consideration. Materials are often raised by hoists but men normally gain access via ladders. For highe ·
working platforms (above 20 m) a ladder tower is the preferred means of access and gives
access to each lift if required.
i:
96
iatively, ladders and landings can be built into the scaffold itself. The distance between
igs must not be more than 9 m. Access holes through landings should not be more than
nm wide and should be as small as practicable in the other direction. ladders should proj: least 1.0 m above each landing. They should be set at an angle of 4 vertical to 1 horizond supported only by the stiles, which should be secured at the top using lashings or proprifixings.
rlNE SAFETY CHECK
Night
Ladders should be boarded up to prevent unauthrised access to the scaffold
Lights should be placed so that the public are protected from accidentally damaging
either themselves or the scaffold e.g. by driving into it
Check that warning signs are in position
Morning
Make sure that scaffold has not been interfered with, particularly by children, and is safe
for use
Week
:>ry inspections must be made every week and after severe storms by a competent person
rm E91 Part 1 completed
dismantling
The order in which a scaffold is dismantled is not necessarily the reverse of the order of
erection. Generally, scaffolds should be taken down lift by lift and not from one end to
the other, however, reference should first be made to the relevant risk assessment.
:I Awareness
'ndent scaffolds are in common use and are often taken for granted. Whilst independent
ds are straightforward to erect and use, carelessness can result in accidents. An aware! the potential hazards is essential if accidents are to be avoided.
.z----------
·----1111111111111111111111ERECTING AN INDEPENDENT SCAFFOLD
The following diagrams show a typical sequence of erection (for a three man gang).
In some of the diagrams different activities are shown - the sequence is always A,B,C.
1B. Levelled
/
Fix first
/RAC at
lift height
~A.Fixed
C. Fixed
®
Fix first ledger
Position first pair of standards
A. Fixed to standard
below ledger
©
Repeat at other end
Position standard and transom
Fixed to standard
above transoms
\
Fix foot tie \edger
approx 150mm up
from ground
®
®
Fix second ledger
98
Fix foot tie
Place braces in _.
position at both
ends
('j)
Attach braces and check structure is plumb and level
u~u~
scaffold
~
~
Under
~
to butt
wall
~
~
~
~
~
~
~
c
B. Plumb
standard
~
~
~
·~
·~
C. Fix
brace
~
~
~
~
~
Fix intermediate
~rds
"
"'
\
Fix transom
on top of
ledger
I
I
Attach intermediate standards and transom
~
~
~
~
~
~
~
~
~
~~
~
A. Fix permanent main transoms
n top of ledgers
---+--.
B. Fix
facade
•
Position
facade brace
and plumb
standards
C. Plumb standard and fix
bottom of brace
Plumb remaining standards and fix intermediate transoms to suit boards
100
RHANGING SCAFFOLDING
uspension points of hanger tubes shall be securely fixed to prevent their being dislodged
r all potential forces acting upon them.
'hen a hanger tube is coupled to a horizontal tube that is placed across the top of a
1pporting beam a second horizontal tube shall be attached underneath the supporting
)am with a pair of girder couplers. Both horizontal tubes shall be attached to the
1nger with a right-angle couplers.
1eck coupler shall be installed at top & bottoms of all hanger tubes and beneath trapeze
Jes.
henever possible vertical hanger tubes should be in one length where joints are
cessary, the tubes should be single lapped using at least four couplers.
1peze tubes shall be installed approximately 600 mm (2") below the runners (ledgers)
~ssist in erection, modification and dismantling, and also to serve as a secondary sup-
·t should the runner slip.
nners and bearers shall be coupled to hanger tubes using right-angle couplers.
nger tube spacing shall comply with the tube and coupler post spacing requirements for
load duty of scaffold.
east one board bearer shall be installed when the hanger spacing is more then 1.5 m
~ apart in the longitudinal direction.
y drop-forged girder couplers shall used for the support of hanging scaffolds.
ssed girder couplers shall not be used for the support of hanging scaffolds.
Underhanging Scaffolding:
c.c.
RIGHT ANGLE
COUPLER
PAIR OF GIRDER
COUPLERS (TYP.)
B
~
__.,....:
GIRDER
~I
•
I
I
II
HANGER
TUBES
....,
•
I
I
TOEBOARD
1;I<
~
0
N
;:
c.c.~
c.c
!~
I•
;~
MIDRAIL
tc.c.
, LOWER
PLATFORM
~~~t~~R~~INGER
llii
.,,,
1
TUBE FIXING!l
:
{
LADDER
BEAM
SECTION
A-A
=ljl~==="
c.c.
SECTION
B-B
W\J SUD Middle East L.LC
UNDERHUNG SCAFFOLD
11JV®
Eng. Hassan Farrou h
TUV/TR/SCA/SU p/DXB/002, Reva
Birdcage Scaffold Cont.
•
The weight loading is not to exceed 0.75 KN/m2
•
Ledgers and transoms are fixed to the standards with
•
right angled couplers, except for the working lift.
Uses
•
To access ceiling spaces for-:
Lighting
Sprinkler Systems
Ventilation
Ductwork
Painting
•
Other uses -:
•
Protection for re-roofs in factories
Crash decks in new builds
t
104
-~r
ternal Bracing
here possible the birdcage can be secured by
!ting the walls of the building or fixing tie tubes
1ere ever possible removing the need for bracing.
wever where scaffolds have more than 11
1ndards in a line it is not possible to rely on the wall
Jports only, because some standards will be to far
m a support in at least one direction, some
icing may have to be essential.
:ernal Bracing
lger and sway bracing should occur at every line
1tandards in each direction, every fifth bay.
free standing birdcage scaffolds plan bracing
f have to be considered.
..........
--------------------~~~Single Lift Birdcages
•
Special attention must be paid to the bracing of the
•
lift height if less than 2.5 metres, the absence of a
•
branced upper lift means the stability of the deck
•
comes from the bracing in the base lift only.
•
Therefore the braces in the base must be positioned
•
and fixed correctly.
Single Lift Birdcages Cont.
•
The standards should be connected with a foot tie in
•
alternate bays in both directions to form boxes.
•
Diagonal bracing of alternate boxes in 2 directions,
•
ledgers & transoms should be joined with sleeves & spliced.
•
No storage of materials unless storage areas have
•
been specially designed.
106
dcage Safety Checks
~ck sole boards are in position so that the total
ght is distributed as widely as possible. Base
les of standards are secured to sole boards.
~ck standards are not more than 2.1 m apart in
:h direction; must be vertical and in line.
~ck ledgers are level and in line, also spacing of
1soms.
clcage Safety Checks Cont.
ick diagonal bracing in both directions is securely
d with swivel couplers.
ick security of ties.
ere transoms and ledgers butt the wall, check
·e is no gap. Packing may be needed to prevent
iage to the wall.
Birdcage Safety Checks Cont.
•
Check the security and condition of boards, toe
•
boards and guard rails.
•
Check the load on the working platform is evenly
•
spread, the platform must not be overloaded.
•
Materials should be stacked near the standards.
•
Where necessary brick guards should be used
•
Check the ladders provided for access are correctly
•
supported or secured and extend at least 1.05m or 5
•
rungs above the platform level unless suitable
•
handholds are available.
CAGE ACCESS SCAFFOLDS
iirdcage scaffold is so called because it resembles a cage. It is normally used inside buildJ provide a platform for working on ceilings, soffits or in the installation of lighting or ventior sprinkler systems. Small jobs would generally be done using a tower or hydraulically
led aerial platform where possible, but for larger projects involving longer periods of time,
~age scaffold is required.
tffold is constructed using standards arranged at regular intervals in parallel lines, usunly spaced. Standards are laced together with a grid of ledgers and transoms at every
it and the top lift is boarded out to provide the working platform.
.........................______________
_
~~~
SCAFFOLD REQUIREMENTS
The requirements specified for birdcage access scaffolds are fully set out in BS 5973 and very
.according to whether the birdcage is a single lift or has more than one lift. For single lift birdcages particular attention must be paid to bracing.
These requirements are summarised below:
Maximum Loading
0.75KN/m2 (equivalent to 1 man every square metre)
Standard spacing
Max 2.5 m in each direction
Lift heights
1st lift max 2.5 m subsequent lifts max 2.0 m
Edge bays
Width of edge bays may be three, four or five boards to accommodate the access requirements
for the scaffold
Ledgers Transoms and fittings
Ledgers and transoms should be fixed to standards and to each other with right angle couplers.
At the working lift, transoms may be fixed to ledgers with putlog clips to enable boards to be
laid.
Bracing
Braces may be fixed from ledger to ledger or to standards using swivel couplers. When ledger
bracing is used, a foodtie is required to receive the lower end of the brace on the first lift. One
brace must be provided for every six verticals in each line in both directions. If the birdcage is
fully butted at all levels, then braces can be omitted.
Tying and butting
Stability may also be provided by butting tubes against existing structures. But if only one wall is ·
available it is necessary to provide a push-pull fixing. Where two parallel walls are available,
tubes can be butted against both walls. No vertical should be more than six tubes away from an , '
edge or other restraint point. One restraint should be provided every 32 m2 of vertical face
CONSTRUCTION
Foundations
Great care must be taken when scaffolds are erected on highly polished wood block, mosaic,
marble and similar floors. if necessary a protective layer of suitable material must be placed
under the sole boards.
'IS
With birdcage scaffolds the floor of the building has to carry the full weight of the scaffold and ~d
load. Sole boards are therefore necessary to help distribute the load as widely as possible ·a ·.
they should always be set at right angles to beams or joists.
110
f>lates and Standards
>lates must be placed on sole boards to receive standards. These should be nailed or
id to the sole boards if there is any danger of movement. Standards should be plumbed
nts in alternate standards staggered in order to obtain strength and stability.
rs
rs should be fixed in a horizontal plane at all times. It is advisable to fix the first lift at 2.5
subsequent lifts at 1.8 m - 2 m canters. (The British Standard recommends that the first
cimum should be 2.5 m, subsequent lifts at 2 m maximum).
>ms
i-working lifts, transoms should be fixed to the standards by right-angle or putlog cou)n working lifts, transoms should be fixed to the ledgers with right-angle or putlog copiers
aced as other scaffolds to support boards evenly. (See Table 3 page 19).
~lly, one transom should be fixed in each bay, not more than 300 mm from a standard.
in transoms must be staggered in order to obtain maximum rigidity and safety.
19
y is obtained by diagonally bracing to the full height of the scaffold at each corner in both
ms, particularly if it is not possible to include ties. (See under Scaffold requirements
te.)
s normally achieved by butting walls with alternate ledgers and transoms. (Ends of tube
1ve to be padded to prevent damage.) Alternatively box or reveal ties may be necessary.
is should be provided throughout the scaffold except where access is required, and at
1 alternate bays in both directions to form boxes. (See under tying and Butting).
19 Platform
>rking platform must be close boarded a minimum of 600 mm wide and if 3.9 m boards
id, each board must span at least four transoms. Hand-rails and toe-boards must be
id where the space between the decking and the wall exceeds 15 mm. These must be
n the inside of the standards.
s
; requirements must comply with BS 5973 Section 16. Access is generally provided at the
of the scaffold using ladders and landings.
METHOD OF ERECTION
Two methods of erecting a birdcage scaffold are commonly used. The first uses a foot tie
around a box two bays wide, approximately 150 mm from the base, fixed to standards at each
of the four corners and followed by ledgers at the first lift height. Intermediate standards and
braces can then be fitted.
Foot Tie
I
Erect Standards at each corner and secure with foot ties
2
Transom
I
edger
Attach ledgers at first lift
112
- ",.,,;;.,~·,,~.,,.,;
- -- --- -
- ~~
11
.!
3
Insert intermediate standards and ledgers
4
- -
5
Fix centre standard
6
Attach temporary transoms
114
-
-
_-,,;c
Attach ledgers for second lift
8
Continue facade bracing in a zig-zag or dog leg fashion
115
-
~---
-----
- __:_
---~-~···
This sequence is repeated until the structure is at the required height. Working platform will be
boarded-out and guard-rails and toe-boards fitted.
Safety Checklist
*
Check sole boards are positioned so that total weight is distributed as widely as possible.
Base plates of standards secured to sole boards
*
Check standards not more than 2.5 m apart in each direction; must be vertical and in line ·
*
Check ledgers are level and in line, also spacing of transoms
*
Check diagonal bracing in both directions is securely fixed with swivel couplers
Check Security of ties; at least one every 40 m2 of vertical face. Where transoms or
ledgers butt wall, check there is no gap. Packing needed to prevent damage to wall.
*
*
Check security and condition of boards, toe-boards and guard-rails
*
Check security of couplers and fittings, also condition of fittings
*
Check load on working platform is evenly spread; platform must not be overloaded.
Materials to be stacked near standards. Where necessary brick guards, etc. used
Check ladders provided for access correctly supported and lashed, or clamped, to
fold. Extending at least 1.0 above platform level
*
116
5caf·
~re formed from standard steel scaffold tube and fittings they may either
~
r wheels for mobility, or constructed as stationary towers. They usually
1g platform not projecting beyond the base area and are provided with
.rds. Access to the working platform by ladder may be either inside or
I
I
I
I
E
~
.
~
~-·
·"
.
vice
........ .,.,..·-::
Light duty access towers are used mainly for lightweight work such as painting, simple maintenance, etc. and will not support a load greater than 1.5 KN/m2. This is equivalent to a load of
two men standing per square metre. The safe working load should be clearly displayed on the
working platform.
Heavy duty towers such as camera towers and welding platforms must be capable of sustaining
distributed loads in excess of this figure. These towers are nearly always stationary and expert
advice should be sought in their design and erection.
Stationary towers differ from mobile towers only in as far as they cannot be moved and that they
are more stable. They are generally built to greater heights than mobile towers and are
frequently anchored or guyed in order to give extra stability. Common uses include television
camera towers, welding platforms, lighting, access to working places and routine inspections.
i
l
Foundations
Scaffold towards must always be vertical, even if erected on sloping ground.
Mobile scaffold towers should only be used and moved on firm and level surfaces. Where the
ground is uneven or soft it may be necessary to lay a temporary foundation or track to spread
the weight and permit the tower to be moved more easily and safely. These temporary foundations should be suitably constructed so that the bearing capacity of the ground immediately
below the track is not exceeded at any point. Any displacement of the foundation or track
should be prevented by anchoring it securely.
The anchoring of the track to the ground does not remove the necessity for the tower itself to be
anchored to the ground where this is essential.
Where it is known that a tower is to be used on a suspended floor it should be designed so that
the load is no greater than the bearing capacity of the floor. Expert advice should be sought in
these circumstances.
When guy wires are used or knowledge (weight) is applied to provide stability, the load imposed
on the standards is considerably increased. The foundations must be capable of supporting
these increased loads.
The general rules relating to foundations apply equally to stationary towers. On some sites
adjustable base plates may be needed to ensure the tower is vertical. These must be prevented ,
from falling out of the vertical tubes and any locking devices correctly engaged.
Stability
1
To give stability to a tower the ratio of the nighting moment (the force acting to keep the tower
upright) to the overtuning moment (wind forces or an eccentric weight such as that imposed ~y '
a gin wheel) should be greater than 1.5. In practice this is achieved by limiting the height tot e_
least base ratio. Outriggers may be used to increase the stability of a tower, by effectively
1
increasing the base dimensions.
'
sho~ld,
The height to least base dimension ration of mobile access towers used within buildings
not exceed 3.5 to 1. Mobile access towers adjacent to buildings should have a ratio not rnor
than 3 to 1. No tower should be built with a least base dimension of less than 1.2m.
118
l
>wers these ratios may be increased to 4 to 1 and 3.5 to 1 respectively. These
1 to towers constructed of steel scaffolding materials. Aluminium towers are
·ent criteria apply.
I
Je braced on all sides and in plan at every alternate lift, beginning at the base
deck level.
\
iuys
'ase the stability of stationary towers, guy ropes may be fixed to the tower and
hors founded in the ground. Guidance is given in BS 5973 on the types and uses
upporting free standing towers. There are four common types:
oes attached to the foot lift
1be anchors attached to guys
I in fight anchors
d pin anchors
1rary scaffolding structures subtract should be of 10 mm or 12 mm diameter wire
iuld be attached to the scaffold structure and to the ground tube or anchored by
turn and three bulldog clips.
ptions and methods of use for anchors and guys are not covered in this book.
s or wheels should be selected to suit the size and loading of the towe. The safe
usually marked on the wheels. These must be fixed at the extreme carriers of
ch a manner that they cannot fall out if the tower is moved, or a wheel is out of
3 ground. They must be fitted with effective wheel brakes which cannot be accisd.
1ight such as sand babs, concrete blocks, etc. is used to stabilise a tower, the
castors to take the extra load should be checked.
,5
j be fixed by lashing the stiles of the ladder to horizontal tubes and should be
narrower face. unless it is not practicable ladders must be positioned inside the
en the means of access is outside the structure, consideration should be given to
1e stability of the tower.
for is on the inside, access must be provided through the platform and a hinged
cover provided for the opening. If the ladder is on the outside a hinged handrail
1e provided to ensure safe access, however, the use of external ladders should be
119
'"
___} _
TOWER CONSTRUCTION
The height of the lifts should not exceed 2.7 m. The lowest ledgers and transoms should be
fixed as near to the castors as possible. The tower should be stiffened using diagonal bracing at
approximately 450 to the horizontal on all four faces. Ledgers, transoms and plain braces must
be joined to the standards by right-angle couplers, Standards should be joined with sleeve
couplers or lapped tubes; never with internal spigot pins. All joints should be staggered.
There is a minimum base dimension of 1.2 m. When the tower base is greater than 2.5 m x 2.5
m the weight of the tower hinders it from being moved easily and, for these larger towers, advice
should be sought.
The Working Platform
~e
wdit~
Workingh pladtfobrms shoduld
close boarded
the toe-bohards a nd douh?lek safety drabils. Tdransoms s ou 1 e space at interva 1s not excee ing 1.5 m w en 38 mm t 1c sea11o1 oar s are
used. However, it is recommended that transoms are not more than 1.2 m apart. Where short
boards are used, (for example at access openings) they must be fixed down at both ends to
prevent tipping. It is good practice to do this for all boards.
USE
The user should never apply horizontal forces at the level of the working platform (e.g. by hauling on ropes or cables) and should not lift significant weights up the outside of the tower. Where
gin wheels are used on cantilevered tubes the tower must be specially designed for this
purpose.
Mobile towers should only be used on level ground, never on a slope which might allow them to
run away. Castors should be locked except when the tower is being moved. If there is any doubt
about the adequacy of the brakes, wheels should be checked and if necessary replaced.
Mobile towers should never be moved with men or materials on the working platform. When
moving the tower, this should be done by pushing at the lowest practical point.
Safety Checklist
Foundations
*
Ensure that ground surface is firm and level
*
For stationary towers check that standards are fitted with base plates and that base
plates are securely fixed to prevent lateral movement.
*
If temporary foundations or pathways have been provided for a mobile tower, see that
they are properly prepared.
*
Ensure that suspended floors are not overloaded
*
Check for additional loads which may be imposed when guys or ballast weights are
used.
120
It'·
be vertical and stable
s should be made with sleeve couplers and staggered
I
d Transoms
be horizontal and complete
be fitted to standards with right angle couplers
;t ledgers and transoms fixed as near to castors as possible
1g of transoms 1.2 m - 1.5 m or less
s braced on a sides and in plan at every alternate lift starting at the base lift and
ider deck level
....
that the ladder is lashed top and bottom on each stile. The ladder should be fixed
1arrower side of the tower.
that the foot of the ladder is about 150 mm clear of the castor so that the tower
moved about easily.
'orm
e working platform is permitted
must be in good condition and be evenly supported with correct overhang
ldder access provided there must be only a minimum gap for access to the
platform
d toe-boards
in place and properly secured
~t only correct couplers are used and they are fully tightened
tubes for splits, flattened ends and corrosion
121
-
-~=--- ~~---~:'.!:-__
Castors
*
Ensure that castors are fitted so that they cannot fall off if out of contact with the ground
*
Check that brakes are fitted and in proper working order
*
Check castors are greased regularly and rotate freely
*
Check wheel treads are in good condition
Leading
*
Ensure that the maximum distributed load is not greater than 1.5 KN/m2 and that where
kentledge is used, to ensure stability, the castors are capable of supporting the load.
Ties and Guying
*
Guys should be checked to ensure that tension is correct and that connecting points and
anchors are secure
*
On larger towers, seek advice on methods of guying and on loads imposed by guys
and ties.
NOTE: Towers must be secured against adverse weather, vandalism, etc. When left unattended
122
2
Measure off first lift and fix ledgers
and transoms, level and secured with
right-angle couplers
jards at each corner and
oot tie
3a
I
For mobile towers fit castors, secure
and brake
ces on all four sides and fix
tee
123
5
4
Fix intermediate transoms and deck
out temporary intermediate working
platform
Measure off second lift and fit ledgers
and transoms
7
6.
Add braces and intermediate
transoms
Board out working platform and add
guard-rails and toe-boards
124
I
Ill SCAFFOLDS
:tion
>caffolding may be described as easy-to-use scaffolding which can be assembled by
r inexperienced labour. There are a great many such systems now available, ranging
t duty aluminium alloy access towers to heavy duty steel support structures. They all
lifferent patented locking devices (wedges, locking pins, etc.) and are designed to
specifications, which makes it difficult and sometimes dangerous to interchange one
1ith another. However, the majority of systems are made from standard diameter tubes,
1ey can be used with standard scaffold fittings.
hat specific instruction, training or an erection handbook be provided for the men
my system scaffold. Users should pay strict attention to loading and method of erec>hed in the manufacturer's instructions. There is no national or common specification
n scaffolds. Consequently, car should be taken not to mix different systems.
I
I
I
I
11
Types of System Scaffold
9ms are composed of standards with preformed connectors welded at intervals along
h to which ledgers are fixed with a proprietary clamping or wedding arrangement, as
below.
I
. I
-~
l.JI
I!
Some earlier systems use tubes made into frames - typically H or X shape, to avoid the need for
bracing.
'!"
I',,
f:
'
i'
•
.
'
""'
• "'
Components
Standards come in a variety of lengths and have preformed connectors welded at equal
distances along their length. A spigot arrangement is formed at one end of the standard for
extension purposes; occasionally sockets are found instead.
Ledgers are in varying lengths with connectors welded to each end. The connection is made
when the wedge, cup or bolt is hammered or screwed tight.
Transoms are generally made to receive either four or five boards. The ends of the transoms
are connected to the standards in the same way as the ledgers. Some systems accommodate
traditional scaffold boards and therefore require intermediate transoms.
Braces in each direction are made to fit the different bay sizes. Some systems use standard
tubes and fittings for bracing.
126
Adjustable base plates are essential except on completely level surfaces. In practice these are
often interchangeable between systems. However, care should be taken to establish whether
the adjustable base plate is designed for heavy or light duty use; and the SWL (safe working
load) where necessary.
Coarse & fine
Adjustment
Pin
Adjustable
jack
Base plate
Erection Methods
1.
Foundations are prepared as for other types of scaffold by placing sole boards on firm
ground or timber sleepers; or for long term scaffolds or falsework, by bedding them in a lean
concrete mix. Clearly the type of foundation will depend on the purpose for which the scaffold is
intended.
Sloping or uneven ground can cause problems. Careful consideration should be given to the
starting point of the scaffold. Setting out should start from the highest point and adjustable base
plates used to level the structure.
-';;'•
128
ition base plate and/or adjustable base plates/jacks in roughly the correct place.
out transoms and ledgers for the first bay so they are ready to fix after the standards
n place.
e a pair of standards on two adjustable base plates and loosely fix bottom transom.
I
Ii
.,..
15:·
e-=
==
:i)"
zll •
1'1
5.
Fix transom at head height or above to form a frame
6.
Fix ledger and third standard
7..
Complete bay and adjust jacks to ensure that bottom ledgers and transoms are level
8.
Tighten up wedges/fixing attachments.
130
Deck out as necessary before erecting subsequent bays and lifts as required.
Complete to working lift, out and fix guard-rail and toe-boards, braces and ties as
required.
Where returns are necessary, careful planning is required to ensure the scaffold 'fits'.
This should be done at first lift stage.
131
I
s ____ _
[
1
I
Most manufacturers produce their own literature describing erection and dismantling procedures and this should always be referred to Managers must ensure that the system is suitable
for the work; and that employees are aware of the basic scaffolding rules, particularly those
concerning foundations, bracing, platforms (including guard-rails and tow-boards) and ties.
SAFETY AT WORK
Whatever system of scaffold is used, it is essential that all operatives, regardless of their skill
and experience should have regard to their own safety and the safety of others. This is particularly important when system scaffolds are erected by untrained or semi-skilled operatives. In
these cases careful supervision is even more important and supervisors will need to have a
sound knowledge of basic scaffolding techniques if accidents are to be avoided.
Readers are recommended to study Safety at Work (GE 702) a CITB publication intended
primarily for young people entering the construction industry for the first time, but of value to
adult workers and to all those engaged in their supervision and training.
i
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1. '
J
1
132
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I
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II
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....
Part 3
Amendment of BS EN 12811 :2003
EN 12811-1:2003
:ional annex NB {informative}
~uirements unique to this standard or covered in less detail in BS 5973 (withdrawn)
I
Jle NB. I sets out the differences between EN 12811-1 :2004 and BS 5973:1993
tdrawn).
Table NB.I - Requirements unique to this standard or covered in
less detail in BS 5973:1993 (withdrawn)
Comments
ause/Sub-clause
~ 12811-1
BS 5973
4
4.2.1.3
4.2.1.2
4.2.1.3
4.2.1.4
4.2.1.5
.4.2.2.1
4.2.2.2
4.2.2.3
4.2.2.4
Materials
6.2
Steel tubes are to be such that the aesthetic requirements of
prEN 74-1 for indentation will be respected. Tubes of 2m7 mm
wall-thickness are acceptable in prefabricated scaffold.
NOTE Only prEN 74:1 specifies an indentation limitation.
BS 1139-2. L 1991/EN 74:1988 does not have this requirement,
SD existing couplers have not been assessed.
The default tube in the UK is BS EN 39 type 3, which has about
SO% of the strength of BS 1139-2.1 : 1991/EN 74:1988 type 4
tube. For identification the tubes are stamped with "3" or "4" as
appropriate. BS 5973 was based on type 4 tubes. There was no
corresponding limitation for aluminium.
6.2
Loose tubes, tubes for prefabricated components for scaffold
systems, items used exclusively for side protection and as a
platform unit and its immediate support each have a minimum
nominal thickness which depends on the sepcific material.
BS 5973 limited the tube types to be used. See comments
immediately above.
5
General requirements
5.2
Table 2
There are seven width classes or "ranges" whose minima range
from 0,6 m to 2m4 m. The range of each class is typically 0,3
m. Compliance with the requirements of this clause precludes
the use of ledger bracing.
There were five width classes whose minima range from 675.
8.4.3
The distance between platforms is a minimum of 1,90 m (hs in
Figure 2). There are also other requirements which are illus!rated in Figure 2.
For walk-through scaffold a lift height of 2,0 m was recommended, Table 4 recommended+ 150 mm on the
6.4.1
Platform units should have a slip-resistant surface. A menthod
of determining slip resistance is given in DD 7995:2003, 5,6. BS
5973 referred to BS 2482 for scaffold boards.
'
i
t
l
'
I
r
5.3
~
. 6.4 b)
'-...._
133
.
...
5.4 c)
5.4 d)
5.5
5.5.5
15.4
29.9
It is required that the gaps between platform units do not
exceed 25 mm.
The gaps between boards were to be as small as reasonably
practicable.
It was recommended that the gaps between boards be less
than 75 mm and be covered if there were people below. Unles
sthe board was notched, a 25 mm gap was not
15.9
The platform has a maximum slope of 1 in 5 without cross
battens. The decking had a maximum slope of 1 in 4 without
cross battens.
15.6
15.7
With regard to side protection, EN 12811-1 is in compliance
with the Construction (Health, Safety & Welfare) Regulations
199G.
This clause no longer comphes with the Regulation.
There are specific requirements limiting hole size in fencing
structures (brickguards).
No dimensions were specified.
BS 5973
There is a specific dimensional limitation for adjustable base
jacks.
No requirements were given for base jacks (adjustable bases).
5.7.4
BS 5973
Minimum overlap in joints between standards (engagement) is
specified.
No requirements were given for minimum overlap in joints
between standards (virtually only relevant to prefabricated.
5.8.1
16.1
2S.5
Figures
11 and
For access between levels, vertical ladders are implicitly
excluded. BS 5973 gave traditional dimensions for setting up
ladders. Vertical ladders were not precluded by BS 5973.
30.2
For stairways, detailed dimensions are specified. See also 5.8.2
Equation 1. In the UK, a class B stair conforms to the requirement for safe and ergonomic means of access. No requirements were given for dimensions to stairways.
16.2
30.2.2
For an access opening in a platform the minimum width is 0,45
m, the length is 0,60 m and side protection is specified. It was
recommended that an access hole have a maximum width of
500 mm and a length as small as preacticable. It was recommended that the gaps in the decking (access openings) be as
small as practicable to allow access from lift to lift up the ladder
or steps.
5.7.3
5.8.2
5.8.3
Requirements for structural design
6
6.1.3
Table 3
6.4.1
Table 1
Six load classes are specified, with the only restriction of use
being a bar on naterial storage on the lowest class. This class is
only for global loading, as all platforms are required to be class
2 or higher, see 6.2.2.1. There are various steps to accommodate most national practices. Others are possible in
Five load classes were specified.
134
BS 5973
There are three complex requirements in addition to the "class"
uniformly distributed load (UDL).
Basic scaffold design is based on the UDL. Normally the additional criteria will only be used to justify generic solutions.
Only the UDL is to be carried to the base of the scaffold.
Requirements were only give for UDL.
BS 5973
For loading on the wording area, load class 1 platform units
have to be capable of supporting class 2 loading.
No additional requirements above the wording UDL were given
for loading on the working area.
BS 5973
It is not possible to specify a lower load than that on the main
platform for cantilevered portions of a wording area within 250
mm vertically.
There was no equivalent clause for cantilevered portions of a
wording area.
Where such a disparity is appropriate, the lower loading should
be specified, with the higher loading specified on a limited part
of the platform.
29.2
Birdcage scaffolding loaidng can have any loading.
A BS 5973 birdcage was for access only with a loading of 0, 75
kN/m2.
39.10
A horizontal wording load allowance of 2,5% of the UDL or 0,3
kN per bay parallel or perpendicular to the facade is specified.
BS 5973 only considered wind.
6.4.1
For access routes, landings may have a loading different from
the contiguous platform.
There was no equivalent clause for access routes.
30.2.1
For access stairways, detailed loadings including 1 kN/m2 are
specified. However, a concentrated (point) laod of 1,5 kN is
required in the design of individual components.
For access stairways in towers, a minimum load of 2,0 kN/m2
BS 5973
Side protection loads in varous directions are specified, including fencing structures (brickguards) adn toeboards. No loading
requirements were given for side protection.
34,9,
39.3.4.
36.2.3
EN 12811-1 states that an allowance for snow and ice loading
on a working scaffold may be required by national regulations.
Effects of icing were considered.
Snow might be ignored for temporary buildings if short term.
See also BS 6399-3.
39.10
For wind loads, EN 12811-1 has both a location factor CB
(permeability of facade) and a shape factor ct. Likewise for
clade scaffolds Annex A gives data.
I
23.1
24,1
26.3
Dynamic loads moving vertically are represented by a 20%
increase in the weight of the item. Dynamic loads moving horizontally are represented by a 10% increase in the weight of the
item.
BS 5973 specified 25% vertically.
For cantilever bays an impact factor of at least 25% of the
largest lifted load was taken into account.
For cantilever beams konwnimpact laods were doubled and
added to the load. It was recommended tht steel bolts have a
minimum safety factor of 3,3.
6.2.9
Table 1
The basic load combination is for two platforms; one loaded
fully, one at 50%.
Typically, the load combination was given for two platforms, but
in many cases the user will require more platforms in active.
6.3
BS 5973
Deflection limits are set for decking and side protection. There
was no equivalent clause for deflection.
6.2.8
Product manual
7
7
21
A product manual is specified.
Such a manual has to be supped by a manufacturer who offers
a product within the scope of EN 128-11 for which there is no
existing standard. It could also apply if a contractor uses
custom-made equipment. It is a requirement of BS EN 12810-1.
The product manual should also contain dimensions and
8
Instruction manual
8
This clause sets out in more detail, what the section of a product manual about site use should include.
There was no equivalent clause for instruction manuals.
BS 5973
Work on site
9
9.1
9.2
Section 3
This clause, in effect, requires that the construction and use is
coherent with the design.
Work on site was covered in Clauses 18 to 20 inclusive.
11
12
This clause is an attempt to emphasize that the responsibility
for verification of foundation suitability is properly delegated.
This clause gave some details of different types of foundations.
This clause gave guidance on inspections of scaffold which
includes foundations.
National annex NC (informative)
Aspects of structural design covered by this standard but not by BS 5973 (withdrawn)
Table NC.I lists the aspects of structural desing covered by this
standard but not by BS 5973 (withdrawn). These should be taken into
account when designing by hmit state.
11
Table NC.I - Aspects of structural design covered by this standard
but not by BS 5973 (withdrawn)
Comments
Clause
Sub-clause
10
Structural design
10.1.1
Tests may be used to supplement the calculations for structural design (see
also 10.2.4.2)
10.1.2
It is assumed that ties transmit no vertical force. The tie is free to hinge in
any direction form the facade, and the only forces allowable are direct
tension or compression and lateral shear.
10.2.2.1
If the relevant structural Eurocodes are not followed, it is a requirement that
the imperfections given in 10.2.2.2 ae adopted for use in global.
10.2.2.2
It gives permited assumptions for angular imperfection.
10.2.3.1
This gives information on spigot strength.
10.2.3.2
10.2.4.3
In conjunction with Annex B, these give calculation methods for adjustable
base jacks.
10.2.3.4.2
It enables the cruciform resistance of class B couplers to be taken into
10.3.1
For the determination of internal forces and moments, elastic methods are
used except for adjustable bases (10.2.4.3).
10.3.2.1
Simplified partial (safety) factors are used, resulting in an overall factor for
steel of 1,65 (1, 1 x 1,5), little different from permissible stress .
10.3.3.2
For tubular members an interaction equation is provided for the combination
of internal forces .
10.3.3.3
Where rigid connections between tubular members do not confirm to
10.2.3.1, structural design checks are to include bending, shear and
.
.
.
.
. 10.3.3.4
For components of the side protection the maximum eformation is 300 mm at
any point.
10.4
Global or positional stability is verified in accordance with BS EN 12812. The
three aspects are overturning, sliding and uplift.
. Annex A
Wind loads on clad working scaffolds
·,
This informative annex gives information on wind loads on clad scaffolds.
\Annex B
Base jacks; data for calculation
'!
!
This informative annex gives methods of calculation for characteristic resislance and deformations of base jacks.
137
I.
L
Table NC.2 - Aspects of structural design covered by this standard
but not by BS 5973 (withdrawn) (Continued)
Clause
Sub-clause
Annex C
Comments
Characteristic values of the resistances for couplers
This mandatory set of data is very similar to prEN 74-1, but makes no reference to it.
The vaules given are for characteristic resistances and not for safe working
loads. NOTE A change in value of the bending moment of friction type
sleeve couplers is expected to be included in a forthcoming CEN
138
fOFTERMS
acade. A facade which does
1e fixing of through ties or
~ties.
tiase plate. A metal base
ving a screwjack
orehead. A forkhead fitted
ed spindle and nut to give
1ight.
Component cast or fixed
ng for the purpose of
Bolted tie. An assembly of nuts, bolts,
anchors, rings or tubes fixed into the
surface of a building.
Box tie. An assembly of tubes and
couplers forming a tie for the scaffold by
enclosing a feature such as a column.
Brace. A tube place diagonally with
respect to the vertical or horizontal members of a scaffold and fixed to them to
afford stability.
l.
'. A pin or tube driven into
approximately 450 to the
1rovide an anchorage for a
metal plate with a spigot
the load from a standard
ther load bearing tube.
e between two adjacent
g the face of a scaffold.
te distance between the
~djacent standards mea1lly.
clip for fixing a board to a
A board placed between
the building on extended
Jp-up bracket.
1g. See brick guard.
t A softwood board
thers to form access,
s and generally used for
>nents such as toe-fold.
Brace - facade or face. A brace parallel
to the face of a building.
Brace - knee. A brace across the corner
of an opening in a scaffold to stiffen the
angles or to stiffen the end support of a
beam.
Brace - ledger or cross. A brace at right
angles to the building.
Brane - longitudinal. A brace in the
plane of the longer dimension of the
scaffold, particularly in birdcages.
Brace - plan. A brace in a horizontal
plane.
Brace - transverse. A brace in the plane
of the shorter dimension of the scaffold.
Bracket - hop - up or extension. A
bracket to attach (usually to the inside of
a scaffold) to enable boards to be placed
between the scaffold and the building.
Brick guard. (Also retaining boards). A
burner, usually of coarse mesh filling the
gap between the guard-rail and toe-board, and sometimes incorporating one
or both of these components.
·"
Bridle. A horizontal tube fixed across an
opening or parallel to the face of a building to support the inner end of a putlog
transom or tie tube.
Coupler - purlin, rafter or ridge. Special angle or variable angle couplers for
joining members in sheeted buildings
and roofs.
Bridle - inside or outside. A bridle
either inside or outside a building wall.
Coupler - putlog. A coupler used for
fixing a putlog or transom to a ledger, or
to connect a tube used only as a guard-rail to a standard.
Bridle - vertical. a vertical tube performing the same function as a bridle.
Coupler - right-angle. A coupler used to
join tubes at right-angles.
Butting transoms. A transom extended
inwards to butt the building to prevent the
scaffolding moving towards the building.
Coupler - sleeve. A coupler used to join
tubes at right-angles.
Butt tube. A short length of tube.
Coupler - supplementary. coupler(s)
added to a joint to back up the main
coupler taking the load when the estimated load on the joint is in excess of the
safe working load of the main coupler.
Butting tube. A tube which butts up
against the facade of a building or other
surface to prevent the scaffold moving
towards that surface.
Castor. A swivelling wheel secured to
the base of a vertical member for the
purpose of mobilising the scaffold.
Coupler - swivel finial. A coupler to fix a
tube across the end of another in the
same plane but at an angle, as the handrail to a staircase.
Check coupler or safety coupler. A
coupler added to a joint under load to
give security to the coupler(s) carrying
the load.
Crane - jib. A small crane specially
adapted for pivotal mounting to a scaffold
tube.
Chord. The principal longitudinal
member(s) of a beam or truss.
Decking. The board(s) or units forming
the working platform.
Chord stiffener. A tube fixed at right
angles to the chord of a prefabricated
rafter, beam or truss for the purpose of
preventing buckling.
Dowel pin. See pigot pin.
End guard-rail. A guard-rail placed
across the end of a scaffold or used to
isolate unboarded part.
Coupler - fixed finial. A coupler to fix a
tube across the end of another at right
angles in the same plane, as in the
guard-rails.
End toe-board. A toe-board at the end
of a scaffold or at the end of a boarded
portion of it.
Coupler - parallel. Accupier used to join
two tubes in parallel.
End toe-board clip. A similar device to
the tow-board clip for use on end toe-boards.
140
~ spigot. A device design
d grip the inside of a tube.
,ining tubes.
1bnormal. A facade which
::irmit the fixing of through ties
1able ties.
ace. Face brace. A brace
he face of a building.
ormal. A facade which
fixing of through ties or non--
Guy anchor. A pin or tube driven into the
ground at approximately 45° to the horizontal to provide an anchorage for a
rope.
Height. The height measured from the
foundation to the top assembly of ledgers
and transoms.
Hope-up or extension bracket. A
bracket to attach usually to the inside of
a scaffold to enable boards to be placed
between the scaffold and the building.
~s.
general term embracing
s other than couplers.
A U-shaped housing for
n the end of a tube to accept
Independent tied scaffold. A scaffold
which has two lines of standards, one
line supporting the outside of the deck
and one the inside. The transoms are not
built into the wall of the building. It is not
free standing, but relies on the building or
stability.
· rocking or swivel. A
1ccept bearers at a range of
Inside board. A board placed between
the scaffold and the building on extended
transoms, or hop-up brackets.
or block. A single pulley for
ttached to a scaffold for
wering materials.
Interlock pin. See spigot pin.
horizontal distance between
of two consecutive steps of a
red on a horizontal line.
A member incorporated in a
prevent the fall of a person
)rm or access way.
Jost. A vertical tube,
puncheon supporting a
md. A guard-rail placed
ind of a scaffold or used to
arded part.
Jib crane. A small crane specially
adapted for pivotal mounting to a scaffold
tube.
Joint pin An expanding fitting placed in
the bore of a tube to connect one tube to
another coaxially (see spigot).
Kentledge. Dead weight, built-up or
added to a structure to ensure adequate
stability.
ii
I
Ledger. A longitudinal tube normally
fixed para/le/ to the face of a building in
the direction of the larger dimensions of
the scaffold. It acts as a support for the
putlogs and transoms and frequently for
tie tubes and ledger braces and is fixed
to the adjacent standards.
Ledger or cross brace. A brace at night
angles to the building.
Lift. The assembly of ledgers and transoms forming each horizontal level of a
scaffold.
Lift - foot. A lift erected near to the
ground.
Parallel coupler. A coupler used to joint
two tubes in parallel.
Plan brace. A brace in a horizontal
plane.
Prop tie. An assembly of telescopic
props and/or scaffold tube jacked or
wedged between the floors of a storey
inside a building and including a tie tube.
Puncheon. A vertical tube supported at
its lower end by another scaffold tube or
beam and not by the ground or on a
deck.
Purlin. A tube secured to the rafters of a
building and parallel to the ridge for the
purpose of attaching the root covering
and to act as a top chord stiffener for the
rafter beams.
Lift head room. The clear distance
between a platform and the tubular
assembly of the lift above.
Light height. The vertical distance
between two lifts, measured centre to
centre.
Lip tie. An assembly of tubes forming an
L or J shaped hook round a part of a
building.
Push/pull tie. A tie which acts to prevent
the scaffold moving either towards or
away from the building, e.g. a reveal tie,
a box tie, a double lip tie, a bolted tie with
a tie tube.
Lip tie - double. A lip tie which is a
push/pull tie, i.e. has a cross tube on the
back and front of the wall.
Putlog. a tube with a blade or flattened
end, to rest in or on part of the brickwork
or structure.
Longitudinal brace. A brace in the
plane of the longer dimension of the
scaffold, particularly in birdcages.
Putlog adaptor. A fitting to provide a
putlog blade on the end of scaffold tube.
Putlog coupler. A coupler used for fixing
a putlog or transom to a ledger, or to
connect a tube used only as a guard-rail
to a standard.
Movable ties. A tie which may be temporarily moved for the execution of work.
Normal facade. A facade which permits
the fixing of through ties and non-movable ties.
Rafter and rafter beam. A transverse
tube, beam or truss in a building spanning across a root or from the eaves to
the ridge.
142
An inclined load-bearing tube.
Scaffold - free standing. A scaffold
which is not attached to any other structure but is stable in itself or, if necessary,
stabilised by rakers and I or anchors.
ng bar. A strip or device fixed
the top of the decking to hold it
Scaffold - independent tied. A scaffold
which has two lines of standards, one
line supporting the outside of the deck
and one the inside. The transoms are not
built into the wall of the building. It is not
free standing, but relies on the building
for stability.
ng boards. See brick guard.
screw pin. A fitting used for
ng a reveal tube between two
1g surfaces.
tie. The assembly of a reveal
:h wedges or screwed fittings, and
required, fixed between opposing
f an opening in a wall together
'tie tube.
Scaffold - putlog. A scaffold which has
one line of standards to support the
outside edge of the deck and utilises the
wall being built or the building to support
the inside edge.
tube. A tube fixed by means of a
d fitting or by wedging between
1osing surfaces of a structure, e.g.
n two window reveals, to form an
to which the scaffolding may be
Scaffold - slung. A scaffold hanging on
tubes, ropes or chains from a structure
overhead. It is not capable of being
moved or lowered.
ngle coupler. A coupler used to
es at right-angles.
Scaffold - suspended. A scaffold hanging on ropes which is capable of being
raised and lowered.
Sheeting. Horizontal, vertical or inclined
sheets of material, such as corrugated
metal or plastic sheet, attached to a
scaffold in order to provide protection
from the effects of weather or alternatively to protect the surrounding area
from the effects of works being carried
out from the scaffold structure.
he vertical distance between two
fa stair.
~ clip or sheeting clip. A fitting
g roof or wall sheeting to tubes in
es without the need for holes in
eting.
d. A temporary structure which
s access, or from which persons
r which is used to support materi1t or equipment.
Sheeting hook. A threaded rod hook
with a washer and a nut used for attaching sheeting to tubes.
Sheeting rail. A horizontal tube fixed to
the verticals of a scaffold to support the
sheeting.
d board. A softwood board com'ith others for form access, workforms and generally used for
ve components such as toe-on a scaffold.
143
'•
----:::::--:::---:---.-:----------===--~!r""
Siii. See sole plate.
Sway transom. A transom extended
inwards in contact with a reveal or the
side of a column to prevent the scaffold
moving sideways
Skirt. A short portion of vertical sheeting
usually adjacent to the edge of a roof to
give extra protection to the area enclosed
immediately under the roof.
Swivel coupler. A coupler used for
joining tubes at an angle other than a
right angle.
Sleeve coupler. An external coupler
used to join one tube to another coaxially.
Swivel finial coupler. A coupler to fix a
tube across the end of another in the
same plane but at an angle, as the handrail to a staircase.
Sole board. A timber, concrete or metal
spreader used to distribute the load from
a standard or base plate to the ground.
Tension pin. See spigot pin.
Spigot. An internal fitting to join one tube
to another coaxially (see joint pin).
I
I
I
I
Tie tube. A tube used to connect a
scaffold to an anchorage.
Spigot - expanding. A device designed
to expand and grip the inside of a tube.
Used for joining tubes.
Tie or tie assembly. The components
attached to an anchorage or the building
or framed around a part of it or wedged
or screwed into it. Used with a tie tube to
secure the scaffold to the structure.
Spigot pin. A pin placed transversely
through the spigot and the scaffold tube
to prevent the two from coming apart.
Tie - bolted. An assembly of nuts, bolts,
anchors, rings or tubes fixed to the
surface of a building.
Spine beam. a longitudinal main beam
spanning from end to end of a roof at the
ridge or eaves.
Standard. A vertical or near vertical
tube.
Tie - box. An assembly of tubes and
couplers forming a tie for the scaffold by
enclosing a feature such as a column.
Standards - pair of. The standards
forming the frame at right angles to the
building.
Tie - double lip. A lip tie which is a
push/pull tie, has a cross tube on the
back and front of the wall.
Supplementary coupler. Couper(s)
added to a joint to back up the main
coupler taking the load when the estimated load on the joint is in excess of the
safe working load of the main coupler.
Tie • lip. An assembly of tubes forming
and L or J shaped hook round part of a
building.
Tie - movable. A tie which may be temporarily moved for the execution of work.
144
Tie - prop. An assembly of telescopic
props and/or scaffold tube jacked or
wedged between the floors of a storey
inside a building and including a tie tube.
Transoms - butting. A transom
extended inwards to butt the building to
prevent the scaffolding moving towards
the building.
Tie - push/pull. A tie which acts to
prevent the scaffold moving either toward
or away from the building, e.g. a reveal
tie, a box tie, a double lip tie, a bolted tie
with a tie tube.
Transom - needle. A transom extended
from or into a building.
Transom - sway. A transom extended
inwards in contact with a reveal or the
side of a column to prevent the scaffold
moving sideways.
Tie - reveal. The assembly of a reveal
tube with wedges or screwed fittings and
pads, if required, fixed between opposing
faces of an opening in a wall together
with the tie tube.
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~
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Vertical bridle. A vertical tube performing the same function as bridle.
Width. The width of a scaffold measured
at right angles to the ledgers from centre
to centre of the upright. Sometimes
designated by the number of boards,
within the uprights and the number
beyond the uprights on extended transoms.
Tie - through. A tie assembly through a
window or other opening in a wall.
Toe-board. An upstand normally at the
outer edge of a platform intended to
prevent materials or operative's feet from
slipping off the platform.
~ Toe-board - end. A toe-board at the end
'~
t~
Working platform. The deck from which
building operations are carried out.
of a scaffold or at the end of a boarded
portion of it.
Toe-board clip. A clip used for attaching
toe-boards to tubes.
Toe-board - end clip. A similar device to
the toe-board clip for use on end toe-boards.
Transom. A tube to connect the outer
standards to the inner standards or
spanning across ledgers to form the
support for boards or units forming the
working platfom.
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