Practical Scaffolding

Module One
Published by CITB, Bircham Newton, King’s Lynn, Norfolk, PE31 6RH

 Construction Industry Training Board 1982

CITB is registered as a charity in England and Wales (Reg No 264289)

and in Scotland (Reg No SC044875)

First published 1988

Revised 1997, 2006, 2008, 2015

CITB has made every effort to ensure that the information contained within this publication is
accurate.
Its content should be used as guidance only and not as a replacement for current regulations, existing
standards or as a substitute for legal advice and is presented without any warranty, either express or
implied, as to its accuracy. In no event will CITB be liable for any damages arising from reliance upon
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2 CITB 2015
Contents:

Introduction 4

Definitions 5

Couplers 6

Scaffold tubes 9

Scaffold boards 10

Foundations 11

Standards 12

Ledgers 12

Transoms 12

Bracing 12

Scaffold ties 13

Working platforms and decking 19

Load classes 20

Access & egress 21

Gin wheels 22

Knots 23

Free-standing scaffolds 24

Birdcage scaffolds 26

Dismantling scaffolds 27

3 CITB 2015
Scaffolding – Introduction

Where work cannot be safely done from the ground or from part of a building or other permanent
structure, there shall be provided either scaffolding or where appropriate ladders or other means of
support, all of which shall be sufficient and suitable for the purpose, and where reasonably
practicable, be suitable and sufficient to provide safe access to and egress from every working place.

Scaffolds shall be erected by trained scaffolders or other competent persons possessing adequate
experience of such work. All material for any scaffold shall be inspected before use, by a competent
person. Materials used shall be of suitable quality and in good condition, and they shall be free from
patent defect likely to affect their strength materially. Items not meeting the standards to be
discarded.

Note:
Every scaffold shall be securely supported or suspended. Where necessary be sufficiently and
properly strutted or braced to prevent collapse, and shall be rigidly connected with the building or
structure, unless the scaffold is so designed and constructed as to ensure stability without such
connection.

4 CITB 2015
Definitions

Standard
A vertical or near vertical tube.

Ledger
Horizontal member normally in
the direction of the larger dimensions of the working scaffold. It acts as a support for the putlogs or
transoms, and frequently for the tie tubes and ledger braces, and is usually joined to the adjacent
standards.

Transom
Horizontal member normally in the direction of the smaller dimension of the working scaffold
supported by a ledger or connected to the standards with right angle couplers.

Structural Transom
To add additional strength in the design to reduce lateral movement in the scaffold. Fixed with load
bearing couplers to the standards or ledgers to suit.

Brace
A tube placed diagonally with respect to the vertical or horizontal members of a scaffold and fixed to
them to afford stability.

Tie or Tie Assembly

The components attached to an anchorage or the building, or framed around part of it or wedged or
screwed into it with tie tube. Used to secure the scaffold to the structure.

Guard rail
A member incorporated in a structure to prevent the fall of a person from a platform or access way.

Putlog
A tube with a flattened end, to rest in or on part of the brickwork or structure.

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.

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Reveal Tube
A tube fixed by means of a threaded fitting or by
wedging between two opposing surfaces of a structure,
e.g. between two window reveals, to form an
anchor to which the scaffold may be tied.

Spur/Raker
An inclined load-bearing 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.

Couplers

BS EN12811-1
BS EN74-1:2005

Right angle coupler:

A coupler used to join tubes at right angles to each
other

Minimum SWL Class A -6.1 kN/ Class B- 9.1 kN

Swivel coupler
A coupler used for joining tubes at varying angles.

Minimum SWL Class A -6.1 kN/ Class B -9.1 kN

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Putlog coupler
A coupler used for connecting a putlog or a transom to a
ledger.

Minimum slip resistance 0.63 kN

General fittings

Sleeve coupler Joint pin or spigot

An external coupler used to join tubes in length An expanding pin used internally to join tubes end to
end. Has no slip resistance.
Minimum (Tensional)
Class A - SWL 3.6 kN
Class B - SWL 5.5 kN

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Base plate Girder coupler
A metal plate with a spigot for distributing the load from For connecting scaffold tubes to RSJs. Units must be
a standard/raker or other load-bearing tube. Minimum used in pairs. Loadings refer to manufacturer’s
dimension 150 mm x 150 mm Minimum thickness 5mm. recommendations.

General fittings Gin wheel

Used for raising and lowering components and materials
Reveal Pin to a scaffold structure
Inserted into the end of a tube and adjusted to secure
scaffold in openings (window etc.) for ties of 3.5 kN SWL stamped on the frame.
maximum pull (light duty tie

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Toe board clip Inspection
A clip used for attaching toe boards to tubes. The ability of a scaffold to carry its load is largely
dependent on the strength and condition of the tubes
used in construction. Consequently, tubes must be
inspected to ensure they are:

 Straight
 Free from cracks, splits, bad dents and
excessive corrosion
 Cut square and clean at each end

Tubes through fittings

The standards for couplers do not specify a minimum
distance a tube must project through a coupler (EN74).
Industry recommends that transoms should allow a
25mm projection beyond the coupler.
For all other positions, it is assumed acceptable if the
tube passes through the entire body of the fitting to
function correctly.
Unless the fitting manufacturer recommends otherwise.

Scaffold tubes
Tubes should be manufactured and tested in accordance
with BS EN 39:2001 ‘Specification for tubes for use in
scaffolding’.
Best practice only permits the following types of tube to
be used:

 BS EN 39 type 4 (4mm) galvanised steel tubes

or equivalent.

 High-tensile galvanised steel tubes with a

diameter of 48.3mm, thickness of 3.2mm, in
accordance with BS EN 10210-1.

The following types may not be used without design:

BS EN 39 type 3 steel tubes.

Aluminium tubes.

Other dimension, material or grade, (black

tube)

Repair of tubes
Bent steel tubes may be straightened using a crow or
reeling machine, but bent aluminium tube should be
discarded. Repairing scaffold tubes is a skilled job and
must only be undertaken by specialists.

9 CITB 2015
Common Faults Scaffold boards
Nearly all scaffold boards are manufactured from sawn
and seasoned timber.

Boards should comply with BS 2482 ‘Specification for

Timber Scaffold Boards’. This identifies the types of
wood which may be used in the manufacture of scaffold
boards and recommends a method of testing to assess
their bending strength.
The most common size for a scaffolding board is:
225 x 38mm x 3.9m.

Laminated Veneer Lumber (LVL) and

Composite Plastic Boards
Laminated veneer boards and plastic boards can be used
to erect basic scaffolding provided the target span
quoted by the manufacturer is at least 1.2m and the unit
weight does not exceed that of a 38mm timber
scaffolding board.

Identification of Boards
Each board should be identified by having the following
information clearly marked on it:

• The British Standard number (BS 2482)

• The identification mark of the supplier

• The letter M or V denoting machine or visually graded

• The word ‘support’ followed by the maximum span in

metres over which the board has to be supported
followed by the abbreviation ‘max.’ e.g. BS 2482 AB Co.
M support 1.5 max.

This is normally given on the band or nail plate which

Storage provides board end protection. Alternatively, a special
Scaffold tubes are generally supplied in lengths of identification plate may be used, or this information
6.3 m, shorter tubes are available from stock; for may be branded on the board.
example, transoms of 1.5 m and 1.8 m length. Wherever
possible tubes should be sorted according to length and
stored in racks with their ends flush.

Many boards in use do not comply with this

specification (known generally as Grade ‘A’)
non-standard boards generally reduce the maximum
span between supports to 1.2m to mitigate the risk
of failure.

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Inspection and Maintenance Foundations
Care should be taken of boards in use. No over- The foundations for a scaffold should be adequate to
stressing should be allowed, e.g. that caused by impact carry and dispose the load imposed both locally at each
loading. Boards should not be used as ramps or standard and, in general, to carry the whole weight of
platforms over long spans, nor should they be placed the scaffold.
where vehicular or other loads can be put on them.
Boards showing any evidence of damage from the Base plates
aforementioned, e.g. tyre marks, should be destroyed. The main function of a base plate is to distribute the
load from the standard. Base plates should measure at
Scaffold boards should be cleaned and the bands or nail least 150 mm x150 mm. If the base plate is made from
plates secured or replaced. Split boards may be cut mild steel it should be at least 5 mm thick. If made from
down or repaired using nail plates depending on the other material then it must be thick enough to be
degree of damage. No cut outs, burns, oil stains or capable of distributing the required load. The shank
projecting nails should be present. must be at least 50 mm high.

Boards should not be painted or treated in any way that On surfaces such as steel and concrete, which are of an
may conceal defects, but can be fire-proofed using an adequate hardness and thickness to prevent the scaffold
approved material. tube penetrating into the surface, the uprights of a
scaffold may be placed directly on the surface, although
it is generally preferable to use a base plate.

Base plates must always be used on other surfaces such

as pavements, hard asphalt and timber flooring.

Sole boards
On soils, ash, hoggin, gravel, soft asphalt and any type of
flooring or paving which would be penetrated by an
upright with a base plate beneath it, or if there is doubt
about the surface, there should be a further spreading
of the load by a sole board of timber or other suitable
material.

When a sole board is used, the area beneath any one

standard should be at least 1000 cm2, with minimum
dimension of 220 mm, and a thickness of at least 36mm.
Typically this will be achieved with a 225 x 38mm
scaffolding board cut to a length of 450mm.

As an alternative to two individual sole boards a single

sole board may be provided under a pair of adjacent
standards, provided that the area of sole board
supporting each standard is no less than if two
individual sole boards were used.

Doubled sole boards

Sole boards of a greater thickness or size may be
required for:

 Taller scaffolds
 Loading Bays
 Bridged sections depending upon the number
of lifts supported.

Storage Sloping ground

Scaffold boards should be stacked no more than 20 An engineer should be consulted to check the adequacy
high, bonded together with short timber battens, and of sloping foundations if a gradient exceeds 1 vertical to
placed on level timbers, off the ground for protection 10 horizontal to ensure that the scaffold is stable.
from surface water. Boards should be protected from
weather and have a free circulation of air.

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Excavations, slopes or embankments Ledgers
As a guideline excavations should not be made within Ledgers join the standards together. They should be
1m of the scaffold foundations. horizontal to within 20mm in 2m (subject to a maximum
Scaffolds adjacent to an excavation, edge of a slope or total deviation of 50mm) and fixed with right angle
embankment must have the sole board set back a couplers. The spans between standards is called a bay.
minimum of 300mm.
Joints in ledgers should be made with sleeve couplers.
Scaffolding on pavements Joints in ledgers on the same lift and in adjacent lifts
Proprietary high-visibility plastic plates are often used should not normally occur in the same bay. However,
under the base plates of scaffolding on pavements or when guard rails are to remain permanently in place,
access ways for improved visibility and/or to protect the the absence of a joint in the guard rail may be accepted
surface. They are not a substitute for a sole board. as giving sufficient continuity to the scaffold to permit
Base plates and plastic treader plates may be used to joints in the ledgers above and below it in the same bay.
found a independent scaffolding up to 3 lifts and
free-standing towers and interior birdcages up to 4 lifts. Transoms
Board transoms are placed along the ledgers to provide
Standards supports for the working platforms and are generally
The standards carry the weight of the scaffold and fixed with putlog couplers.
should be very carefully spaced. The transoms at un-boarded lifts will normally be
arranged at the same positions as the boarded
The vertical intervals at which standards are linked to platforms.
one another, i.e. the lift height, is one of the most Transom tubes should be sufficiently long to allow a
important dimensions in scaffolding. This dimension minimum projection of 25mm beyond the couplers.
should be measured on site and maintained in
accordance with the requirements of the design. Structural transoms
Putlog couplers only have a limited capacity to form
Standards should be plumb to within 20 mm in 2 m structural connections. In certain cases it is necessary to
(subject to a maximum total deviation of 50 mm). provide additional transoms connected with right angle
couplers.
Any joints in standards should be staggered. Joints in Structural transoms reduce lateral movement in the
standards of access scaffolds tied to a building may be scaffold and should be fixed with load bearing couplers
made with either joint pins or sleeve couplers. These to the standards or ledgers and fixed within 300mm of
types of coupler have limited load capacity in tension. In the node point.
scaffolds which are free standing or projecting above Tie assemblies may act as a substitute for structural
the level of a building or otherwise subject to forces transoms.
which would produce tension in the uprights, the
standards should be joined in a manner capable of Prefabricated transom units
resisting the applied tension. Prefabricated or system transom units are
manufactured with integrated end connections that are
No more than three out of four standards at the corner directly fixed to both standards and ledgers to form a
of any bay should have joints in the same lift, if there structural connection.
are four joints in the same lift, one of these must be It is possible to erect independent scaffolding without
spliced with a short length of tube. ledger bracing allowing clear access along the working
platform.
Double standards Alternatively, transom units may be used with ledger
Also referred to as ‘Secondary Standards’. bracing to achieve taller structures.

The maximum safe height of a scaffold is limited by the Intermediate transom units
capacity of the standards. Double standards may be Intermediate transom units are typically telescopic
used to achieve the required height under the structural extender transoms that have an extendable section for
design engineer. the support of inside boards.
The secondary standard should be fixed with RAC’s to
the ledgers immediately adjacent to the primary
standard supported on their own base plates. Ledger bracing
Independent tied access scaffolding should
contain ledger bracing, generally on alternate pairs of
standards within 300mm of node point. Any pairs of
standards which are ledger braced should be made into
a continuous series of triangles. In all cases the ends of
the standards should be ledger braced.

12 CITB 2015
When the bay length is 1.5 m or less, the ledger bracing Scaffold ties
may be fixed to every third pair of standards.

The ledger bracing may be fixed from ledger to ledger Building structure
with right angle couplers or fixed to the standards using It should be established, by test if necessary that the
swivel couplers. strength of the building structure at the location of a tie
is adequate to sustain the loads which will be
The direction of ledger bracing is immaterial for the transferred to it. This applies particularly to any
structural stability of the scaffold but it should be pre- proposed use of parapets or architectural features such
planned to take account of the intended use of the as balustrades. It is frequently found that the anchorage
scaffold. value of such features is negligible.

Ledger bracing from the inside ledger to the principle Basic requirements
guardrail of the lift below may be used on unclad Ties have two primary functions of equal importance.
scaffolds provided that every pair of standards is so
braced instead of every alternate pair. In order for the 1) To restrain the scaffolding standards in a vertical
bracing to be effective it must be connected with right- position so they can carry the weight of the structure,
angled couplers. boards, personnel and materials without buckling.

Ledger bracing may be omitted below the first lift to 2) To prevent movement of the scaffold away from the
provide clear access, typically for pedestrians, provided façade.
the lengths of the standards in the lift are not in excess
of 2.7 m. There are five classes of ties:

Sway/façade bracing  Very light duty - safe load in tension of 2.7kN

Sway bracing should be provided to all scaffolds to
prevent movement along the facade of the building.  Light duty - safe load in tension of 3.5kN
One such brace assembly should be provided on every
face at intervals along the scaffold not exceeding 1  Standard duty A - safe load in tension of 6.1kN
brace per 6 bays and set between 35 – 55 to the
horizontal. It need not be fixed where the scaffold is  Standard duty B - safe load in tension of 9.1kN
securely butted between opposing outside or inside
faces of returns or recesses, provided that no length  Heavy duty - safe load in tension of 12.2kN
greater than 6 bays is so fixed against movement in both
directions.
Lines of ties on alternate lifts
The three principal forms of brace arrangement are in
order of preference:

a) Individual tubes set in a zigzag pattern extending

across TWO bays, TWO lifts, the top of the diagonal tube
and the bottom of the next preferably attached at the
same transom or standard

b) A continuous tube, erected as necessary to cover the

whole façade. Only possible for wider façades.

c) I individual tubes set in a zigzag pattern across one

bay fitted to each lift of the scaffold

Plan bracing
The term plan bracing is used to describe bracing
fitted horizontally under a lift. Plan bracing is not
normally required for TG20 compliant independent
except in two cases:

Bridges over openings supported with beams where

plan bracing is used to join and stabilise the beams.
a- 100 % of ties on ledger braced frames
Pavement lifts, which provide clear access for
pedestrians by omitting the ledger bracing below the
first lift, may be stabilised with plan bracing.

13 CITB 2015
It should be established, by test if necessary that the
strength of the building fabric at the location of a tie
position is adequate to sustain the loads that will be
transferred to it. This particularly applies to any
proposed use of parapets or architectural features such
as balustrades.

In general, tie tubes should be connected to both the

outer and inner standards and ledgers.
The suitability of this tying method depends on several
factors including the height of the scaffold, its exposure
to the wind, whether it is clad and whether it is erected
with traditional transoms or prefabricated structural
transom units.

Layout of Ties
Ties should be evenly distributed over the scaffold both
horizontally and vertically. Normally the spacing of lines
of ties should not be greater than 4.0m vertically. b- 50% of ties on ledger braced frames
Typical arrangements of ties that comply with the
requirement are shown below.

Scaffold ties

Through ties (standard duty)

Through ties (figure 1) rely on a tube across the inside of
an opening such as a window in a building.

14 CITB 2015
Through ties (standard duty) Putlog through ties (figure 2) rely on a tube across the
inside of an opening such as a window in a building.

 Position of right angle coupler

Lip ties (standard duty)
Scaffold ties Where it is not possible to use box ties, lip ties may be
fitted (see Figure 4). These consist of an L-shaped
Box ties (heavy duty) arrangement of tubes and couplers to hook the scaffold
Box ties consist of an assembly of tubes and couplers behind parts of the building. They should be
arranged in the form of a square fixed around columns accompanied by an adjacent butting transom to resist
or other elements of the building, being wedged, where inward movement (as shown in Figure 4(D)) to resist
necessary, to resist both inward and outward movement sideways movement. Sway transoms should not be
and to give some degree of lateral restraint. Figure 3 regarded as a substitute for facade bracing. They should
items A & B (heavy duty) and C & D (standard duty) are be coupled to the ledger with load-bearing couplers.
typical examples. Care should be taken to ensure that the strength of any
building feature utilised is adequate, particularly if this is
They should be at the level of the scaffold lift and be a parapet or similar structure.
joined to both the inside and the outside ledgers or
standards. Lip ties may also be used over sills and under lintels. In
these cases, it will be infrequent that the sill or lintel tie
is on a level with a lift of the scaffold and they may be
fixed to the inside uprights only
or to a bridle tube fixed to two inside uprights. They
should be accompanied by adjacent butting transoms
and sway transoms.

15 CITB 2015
 thin so as to reduce shrinkage (a thickness of 10 mm is
recommended). It is not expected that they should
Scaffold ties
spread any load over the surface of the reveal but that
they should grip and protect it at the same time.
Reveal ties The preferred method is to use a reveal pin at one end
In cases where it is impracticable to open windows for of the reveal tube. This consists of a small plate on
tube and coupling ties, the attachment of the scaffold which is mounted a threaded bar and nut. The assembly
may be made by reveal ties which rely on friction (see should be placed inside the bore of the reveal tube and
Figure 5). the nut adjusted until the reveal tube is expanded into
the opening, gripping it with considerable force.
It is recommended that no more than 50%of ties in each
façade should be reveal ties. The tie tube should be fixed to the reveal tube with a
right angle coupler as near as possible to the
Opposing faces of a building’s surface, such as the two end opposite to the reveal pin and in all cases within
opposing sides of a window opening, may be used to 150 mm of the face of the opening. It should also be
make an attachment of the scaffold, usually by means of fixed to the scaffold in two places with right angle
a tube or wedges, or jacked tight between the opposing couplers. Other arrangements may also be satisfactory.
faces. It is frequently necessary to place packing Because reveal ties rely on friction and are usually
between the end of the reveal tube and the surface so packed with timber, they should be frequently checked
that damage does not occur. Timber packs should be for tightness during the life of the
scaffold.

16 CITB 2015
Scaffold returns Buttresses, rakers, ladder towers and
Returns of scaffolds, which are effectively tied around loading bays (very light duty)
the ends of building facades, should be regarded as The stability of a scaffold can be achieved by means
providing an adequate attachment of the scaffold at other than anchorage ties fixed to the surface of the
each lift equivalent to the standard tie positioned at the building.
end of the building façade. The return scaffold should
have façade bracing and be tied in accordance with this Fully braced buttresses, should be regarded as providing
guide. The ledgers of the return scaffold should extend adequate stability for a single bay of the scaffold on
to connect to both inside and outside ledgers of the either side of the buttress.
façade scaffold considered. Both façade and return
guardrails should be connected to the Single unjointed raking tubes of up to 6m in length, fixed
corner upright at every lift with right angle couplers. at alternate standards coupled at the top of the ledger
with a right angle coupler at the second lift, and tied
However, any scaffolding elevations with a return only back to the scaffold, should be considered as providing
at one end must be tied with a standard tie adequate stability for unclad scaffolds up to 6 m high.
arrangement. The raking tube should be external to the scaffold or
fitted from the inside ledger at the top of the second lift
and at an angle of not more than 2 vertical to 1
horizontal. A structural transom shall be fitted at the
second lift within 300mm of each raker and shall but the
building.

Ladder-access towers, loading bays or equivalent fully

braced towers can act as a buttress on independent
scaffolds up to 6 metres in height.

17 CITB 2015
Masonry anchors
An anchorage can be provided by casting in a threaded
socket, or fixing something similar into a part of the
structure itself. Various components are then used to
attach the scaffold. Anchorages and allied components
should have a safe working capacity in combined
tension and shear to suit the circumstances.

A wide variety of anchors are available for fixing into

holes pre-drilled into concrete or sound masonry. Advice
on the correct selection, installation and testing of such
systems should be sought by the design engineer.

18 CITB 2015
Transom spacing where necessary suitable measures put in place to
The spacing of the support transoms vary according to protect persons from injury.
the grade of board and the load class of the scaffold.
BS2482 timber boards of 38mm thickness are available Guard rails
in two strength grades: the normal strength grade Working platforms from which a person may fall should
requires 1.2m transom spacing on load class 1 – 3 and have a principal guard rail fixed to the outer and end
900mm on load class 4, whereas the higher strength faces of the scaffold at a height of at least 950 mm
machine stress graded board require a transom every above the level of the decking. An intermediate guard
1.5m on load class 1 – 3 and 900mm on load class 4. rail is connected below the principal rail so that the gap
The maximum overhang of a board should not exceed between the guard rails, and the gap between the
150mm and should not be less than 50 mm. intermediate guard rail and the toe board, does not
exceed 470mm.
Decking
Any group of boards across the width of the scaffold The guard rails are positioned inside the standards and
should be of the same length, with all boards of the must be connected to each standard with a right-angled
same thickness. coupler. It is permissible to attach an end guard rail with
a putlog coupler at the outer standard; provided the end
38 mm thick boards are the most common in use and guard rail is fixed above the longitudinal rail and the
are supplied in lengths of up to 3.9 m. When these are connection with the inner standard is made with a right-
used and the recommended transom spacing is 1.2 m, angled coupler.
there should be four transoms to each board, if the
recommended transom spacing is 900mm, there should Toe boards
be five transoms. Toe boards and end toe boards should be suitably fixed
to all working platforms to prevent materials or
Boards which are nominally 38 mm thick and less than operatives slipping from a platform.
2.13 m long should not be used unless they are securely They should be suitable strength and be fixed in at least
fixed to prevent tipping. two places, and of such a height that the gap between
the top of the toe board and the bottom guard rail does
Gaps in decking not exceed 470 mm.
The Work at Height regulations require platforms to be The minimum height of the toe board should be 150
constructed without gaps unless measures have been mm and they should be placed inside the standards.
taken to protect people from falling through them, and
to prevent the risk of injury from materials or other Brick guards
objects falling through. Brick guards or other suitable vertical protection are
desirable in cases where materials may fall from the
Platforms with inside boards, for instance a 4+2 scaffold. These screens can be hung
arrangement will nominally have a gap of 50mm from the guard rails and should be prevented from
between the main platform and the inside boards. Such outward movement. Toe boards may be incorporated
a gap is acceptable in tube and fitting scaffolding within the screen and the latter should be capable of
providing a proper risk assessment has been made and, preventing the materials being used passing through.
Independent tied scaffolds
An independent scaffold consists of a double row of
standards, with each row parallel to the building. The Structural transoms are required for independent
inner row is set as close to the building as is practicable. scaffolding clad with sheeting and may be required for
The distance between the lines of standards should be debris netting scaffolds under the industry.
the minimum necessary to accommodate the required
number of boards and toe boards. Prefabricated transom units
It is possible to erect basic independent scaffolds
A variation may be adopted in which the row of without ledger bracing allowing clear access along the
standards nearest to the building can be set back from working platform. Alternatively, transom units may be
the building face. This means that one or two of the used with ledger bracing to achieve taller structures
boards of the platform can be laid between the inside with
row of the standards and the building face.
Façade, face or sway bracing
The main factor in determining the maximum height is Sway bracing must be fixed to every face of a scaffold.
the site location and wind loading for the configuration. Sway bracing can be omitted if the scaffold is six bays
Contractors should provide the client (and the long or under and fixed against movement in both
Inspector) with this information. directions by butting the inside and outside of returns or
recesses.
The standards should be connected with ledgers parallel In certain circumstances it may be required to use an
to the building and fixed with right angled couplers. internal sway brace.
Transoms are then fixed to the ledgers with putlog
couplers to support the recommended platform widths.
Lift heights
Sole boards and base plates should be used under each The lift height for walk-through scaffolds is 2.0m with a
standard as recommended. head clearance of 1.9m.
Other lift heights are permissible, up to 3m in
compliance with industry best practice.
Ledger bracing The first lift height can be a maximum of 2.7m, with a
Ledger bracing is generally fixed to alternate pairs of minimum walkthrough of 2.44m head room.
standards and at the end pairs. Ledger bracing for access Internal edge protection
must be connected from top guardrail to inside ledger The gap between the boarded platform and the work
with rights angled couplers at each standard. This will face can usually be up to 225mm. This is subject to risk
allow the scaffold to be erected to a total overall height assessment. If over 225mm then suitable measures
of 16m in unclad scaffolds. must be taken.
If the client requests that internal edge protection is not
Structural transoms installed this must be recorded on the scaffolding hand
Structural transoms may add additional strength in the over certificate.
design to reduce lateral movement in the scaffold.
Tie assemblies may act as a substitute fixed with load
bearing couplers to the standards or ledgers to suit and
must be fixed within 300mm of the node.

20 CITB 2015
Access and egress

General Landings
The Work at Height guidance requires employers to use The vertical distance between two successive landing
existing structures for access to work at height, where places should not exceed 9.0m. Landing places should
reasonably practicable. For example if a permanent be provided, where necessary in accordance with any
staircase or passenger lift could be utilised to access and risk assessment requirements, and allow for access
egress a tall building at high level, thus avoiding the holes for the user which should be at least 450mm in
need to expose scaffolders to an unnecessary risk of a width measured across the platform, as small as
fall whilst erecting, altering and dismantling a temporary practicable in the other direction, but not less than
scaffolding access tower, then the permanent access 600mm long. The access hole should be adequately
should be used. protected.

Access and egress to and from scaffolding should be

considered using the following hierarchy of access:

1. Staircase
2. Ladder access tower with single lift ladders
3. Ladder access tower with multiple lift ladders
4. Internal ladder access
5. External ladder access

The landing places should be kept clear of all material

and should be provided with guardrails. Toe boards shall
be provided on landing platforms where there is a risk of
falling material or objects.

Industry recognises 3 classes of Ladder:

 Class 1 – Industrial Safe Load of 135kg
 Class 2 – (EN131 Commercial) Safe Load of
110kg
Class 3 – Domestic, NOT SUITABLE for
scaffolding

Work at Height guidance requires risk assessments to

show that ladders can be used if more suitable access
equipment is not justified because of the low risk and
short duration of use.

Every sloping ladder should stand on a firm and level

base and be supported only by the stiles. Where
practicable, it should be set at an angle of 4 vertical to 1
horizontal. The stiles should be securely fixed to the
scaffold at the top by lashings, or by other attachments.

Ladders used for access shall be long enough to

protrude sufficiently above the landing place, preferably
projecting at least 1m above the top landing place with
the landing rung level with or slightly above the level of
the landing platform. If this is not possible then other
measures to ensure a firm handhold should be provided.

Ladders should not be extended by lashing two lengths

together.

21 CITB 2015
Gin wheels
Most scaffolds require at least a simple lifting device to Ring type gin wheels are to be preferred, i.e. gin wheels
raise materials to the necessary working height. Gin with swivel eye fitments to slide over the supporting
wheels are the most widely used. tube and which can be held in position by right-angled
couplers either side of the ring.
The tube supporting the gin wheel should be fixed either
to two standards which have been braced, e.g. a ledger Checks should always be made to ensure that wheels
braced pair of standards in an independent tied scaffold, run freely on their axles – wheels that are too rusted to
or, in the case of a putlog scaffold, to one standard and run easily may be dangerous (Gin wheels are subject to
braced the Lifting Operations Lifting Equipment Regulations
back to the ledger or putlog tube at mature brickwork (LOLER) and should be thoroughly examined every 12
level. months as they are a lifting apparatus.

It should be noted that in the case of an independent Ropes should comply with the appropriate standard.
tied scaffold, where a joint occurs on the inside They should fit snugly into the rim of the wheel and be
standard, between the supporting tube and the working regularly examined; at least every 6 months as they are
platform level. This joint should be made with a sleeve lifting accessories under the LOLER regs. They should be
coupler, if a joint pin is used this joint must be spliced. marked for identification. The most common diameter
for a fall rope is 18 mm.
Suspension point of the gin wheel on the supporting
tube should not be more than A maximum loading of 50 kg applies when the wheel is
750 mm beyond its outer support point. 750 mm from the outer support of the suspension tube.

22 CITB 2015
Knots
The recommended knots to be used when raising or
lowering scaffold components are as shown on this
page, i.e. rolling hitch, timber hitch and figure- of-eight
knot.

23 CITB 2015
Free-standing independent scaffolding
Freestanding scaffolds may be built up to 6m high
provided they are built to the following specification:

 Not more than 6m to the top-working

platform.

 The scaffold is not fitted with sheeting or

debris netting.

 Lift heights do not exceed 2m (2.7m first lift).

Pavement lifts
Ledger bracing may be omitted below the first lift for
pedestrian access to form a pavement lift.
Façade bracing should be retained at the pavement lift
and for the full height of the scaffold.
The pavement lift should be close-boarded. Improved
protection can be achieved by double-boarding with a
polyethylene sheet between the boards.
All standards that are adjacent to public access should
be fitted with hazard tape or preferably foam padding.
The maximum height of the pavement lift is 2.7m and a
minimum of 2.44m of clear headroom must be provided
for pedestrians. The minimum width of a pavement
scaffold is 1.125m.

Stabilising pavement lifts

Three methods are recommended:
1. The pavement lift can be tied at alternate
(ledger-braced) standards at the first lift.
The remaining lifts to be tied as per industry
guidance.
2. Reduce the height of the second lift so that it
is no more than 4.0m from the ground and
tied at alternate (ledger-braced) standards.
3. If the ties occur above 4m then the first lift will
require plan bracing every bay of the
pavement lift.

24 CITB 2015
Free-Standing Towers Tied towers
Industry best practices has provided guidance for the A tower tied to a permanent structure should be
following types of towers erected in the same manner as a tied independent
scaffold.
 Internal towers Guidance includes provisions for sheeting, debris
 External towers netting, and the use of prefabricated transoms.
 Tied towers
 Lift shaft towers Lift shaft towers
Lift shaft towers provide light-duty access to the interior
Maximum heights are determined by base dimensions of a lift shaft.
(see chart below) Lateral movement can be prevented by securely butting
all four sides of the shaft, by achieving this bracing and
Towers required to support greater loads, or greater tying may not be necessary.
dimensions are subject to design. The ledgers and end Where the tower is completely enclosed, guardrails and
transoms must be connected to the standards with right toe boards may be omitted. (Subject to a risk
angled couplers. Board bearing transoms may be assessment).
connected with putlog couplers. The guardrails must be
fixed to the standards with right angled couplers.
Mechanical hoists
The tower should be braced on all four sides. Mechanical hoists are items of proprietary equipment
Alternate lifts should be plan braced, including under designed to convey materials or personnel to different
the top lift. Bracing on internal towers should be within lifts on the scaffold. It is recommended that mechanical
300mm of node point. Bracing on external towers hoists are not fastened to the scaffold.
should be within 100mm of node point.
Mechanical hoists are not usually self-supporting and
The lift heights should not exceed 2.0m. Only one require connections to the building for stability. These
working lift is permitted. At least two lifts of external connections must be made directly to the building
towers should be boarded to help prevent overturning. rather than to the scaffold, if possible, because
External, or towers exposed to the wind should not be otherwise the part of the scaffold supporting the hoist
netted or sheeted. The user should not subject a tower must be specially designed to take into account the
to any significant horizontal forces, which might cause additional loads imposed by the hoist. The supplier of
overturning. Gin wheels may be used to lift a maximum the hoist is responsible for specifying these additional
load of 50KG if the wheel does not project more than loads. Such loads may have both static and dynamic
750mm from the tower. components of significant magnitude.

25 CITB 2015
Access birdcage scaffolds Free-standing
A birdcage scaffold consists of a mass of standards The maximum height of a free-standing birdcage, from
arranged at regular intervals in parallel lines, the base to the top of the platform level, is limited to
usually evenly spaced apart. These standards are laced four times its least base dimension to prevent
together with a grid of ledgers and transoms at every lift overturning, to a maximum of 10.5 metres.
height. The top lift is boarded to form Taller structures are possible but are subject to design.
the access platform for work on ceilings and soffits, e.g. A free-standing birdcage should be braced in each
to fix lighting, ventilation or sprinklers over an inside direction with a continuous diagonal bracing from the
area. base to the top lift.
Long birdcages where both directional braces meet the
Industry provides guidance on the erection and use of top lift, there are a number of bays permitted between
access birdcage scaffolding within an enclosed building without bracing.
and not subject to wind loading.
Guidance is provided on the maximum height, loading 1 Lift: 3 unbraced bays.
and bay dimensions permitted for a birdcage. 2-3 Lifts: 2 unbraced bays.
If the birdcage is to be used externally, or in an open 4-5 Lifts: 1 unbraced bay
structure exposed to wind, it must be specially designed.
A minimum of one bay must be braced in the opposite
Birdcage construction direction.
The lifts are formed from ledgers and principal One must extend to the top lift. The other can extend to
transoms, both connected to standards with right angle the top lift or where it overlaps or meets the other
couplers. brace.
The principal transoms are to be connected to the Securely butted against a permanent structure
standards with right-angle couplers below the ledgers. Birdcages may be of a greater height-to-width ratio if
Board transoms are connected with putlog couplers. they are securely butted against a permanent structure
Any joints in the standards, ledgers and principal at the top lift, provided at a maximum interval of two
transoms should be made with sleeve couplers. bays.
Any joints in the standards and ledgers should be The bracing may be one bay at every frame for every six
staggered. Joints in ledgers at the top lift should be bays in the direction in which the birdcage is restrained.
avoided in the end and penultimate spans. If freestanding in one direction the base to height ratio
If such joints are unavoidable they should be positioned will apply, and will need to be braced accordingly.
within 300mm of the standard. Tied to a permanent structure
Bracing should be provided in each direction to stabilise
the scaffold. As an alternative to butting, the birdcage may be tied at
All bracing should be connected within 300mm of the one end of the top lift in each direction using push and
node; with the first lift bracing connected no more than pull ties, at alternate bays.
300mm above the base plates. Working platforms

Only one lift to be loaded (top lift) but perimeter lifts

Interior birdcage load class may be used to allow access to the walls.
For top lifts supporting load class 2 or 3, the couplers A maximum of one perimeter lift to be loaded at any
connecting the ledgers to the internal standards should time.
be EN74 class B couplers with a SWL of 9.1kN. Loaded to the same load class as the birdcage.
If class A couplers are used (SWL of 6.1kN), a Max. 5 boards wide.
supplementary coupler should be fixed immediately Single lift birdcage
below each main coupler. A foot lift is required for single-lift birdcages.
Bracing must start in the penultimate bays.
Maximum first lift height 2.5m. Bracing should be fitted every four bays in both
Subsequent lifts at no more than 2.0m. directions.

Free-standing
Securely butted against a permanent structure;
Tied to a permanent structure;

26 CITB 2015
Dismantling scaffolds
During dismantling, no component should be removed
which endangers the stability of the remaining
structure.

If dismantling has reached the stage at which a critical

member has to be removed, e.g. a tie or a brace, the
stability of the structure should be assured by fixing a
similar or otherwise adequate member in place, lower
down, before the critical member is removed.

Because of the changes which are made in a scaffold

structure during its working life, it is not safe to assume
that dismantling can be carried out in the reverse order
to the erection. The scaffold, especially its tying and
bracing should be inspected prior to dismantling.

If the scaffold is defective, it should be made good

before dismantling commences.

The procedure of dismantling should be orderly and

planned and should proceed generally from the top in
horizontal sections.

Scaffolds should not be dismantled in vertical sections

from one end towards the other.

These precautions should be observed.

DO NOT remove all the ties.

DO NOT remove the entire bracing first.

DO NOT remove all the intermediate and

board end transoms.

DO NOT remove all the guard rails.

An access scaffold may have been temporarily

stabilised during construction by rakers that
subsequently have been removed. If the level of the
lowest tie point is high, e.g. over entrance halls or above
tall shop windows, temporary rakers or other
structurally adequate means of support should be built
up from the ground to achieve stability of the part-
dismantled scaffold.

27
CITB 2015