access birdcage scaffolds

7/30/2019 Access Birdcage Scaffolds

1/22

Access Birdcage ScaffoldsA birdcage scaffold consists of a mass of standards arranged at regular

intervals in parallel lines, usually evenly spaced apart. These standards arelaced together with a grid of ledgers and transoms at every lift height. The top

lift is boarded to form the access platform for work on ceilings and soffits, e.g.

fix lighting, ventilation or sprinklers over an inside area.

The side bays of the birdcage may also be required to form a normal access

scaffold to the walls supporting the soffit.

There are two types of birdcage:

1. Birdcages with more than one lift height. 2. Single lift birdcages.The standard should be a maximum of 2.5 M in each direction.

The first lift may be up to 2.5 M high if necessary for access below the scaffold

otherwise the lift heights should, in general, be at 2 M intervals.Except for the working lift in the outside bays, a birdcage should have only one

working lift, i.e. the top lift, and the loading on this should not exceed 0.75

kn/M2.

In the case of a birdcage scaffold covering a large plan area, the width of the

edge bays may be reduced to three, four or five boards to meet the

requirements for the particular type of access required round the edges.

Ledgers and transoms should be fixed to the standards with right angle

couplers. In the top lift, transoms should be fixed to the ledgers with putlog

couplers. Transoms to the working lifts in the side bays may be fixed to the

ledgers to provide level support for the decking.All birdcage scaffolds require to be braced and/or tied to ensure they are stable.

The standards have to be adequately braced to be strong enough to carry the

vertical loading. Birdcages should be stiff enough to resist lateral sway and

horizontal loads and be safe from overturning. External birdcages should be

braced to resist wind forces and anchored when necessary.


2/22


3/22

External BirdcageBracing should be provided at the rate of one brace for every six standards in

each line.

Bracing in each direction should preferably be attached to the ledgers ortransoms by right angle couplers or, if this is not possible, to the standards by

means of swivel couplers.

Internal BirdcageWhere an adjacent structure is available, a birdcage should be stabilised from

it. If possible, all four sides should be secured. Where two opposite walls are

available, it is sufficient to arrange tubes to butt against them from each side,

but if only one is available, it is necessary to provide a two-way tie.

The most satisfactory details is to extend the transoms or ledgers. Where they

are to butt both ends, timber packing pieces and reveal pins may be used.

PlatformsThere are no permissible gaps in decking for the platform. Platforms should be

no further than 150 mm from the working edge, unless provided with guardrails and toe boards. Where scaffolds have more than 11 standards in line, it is

not possible to rely on wall support only, because some standards will be too

far from a support in at least one direction. Thus some bracing will be essential,

but can be used in conjunction with tying and butting using intermediate partsof the structure, e.g. columns.

Any birdcage higher than 50 M should be specially designed. As a general rule

alternate rows of standards would be braced.

Single lift birdcages should have special attention paid to the bracing of any

height less than 2.5 M. The absence of the braced upper lifts requires that thestability of the deck is derived from one lift of bracing only, which should

therefore be correctly positioned and fixed.

The standards should be supplied with foot ties in at lease alternate bays in

both directions to form boxes. Diagonal bracing of alternate boxes in two

directions should be fixed. Ledgers or transoms should be joined with sleeve or

parallel couplers. No materials should be stored on a birdcage unless the

storage areas have been specially designed.


4/22

Independent ScaffoldsHere is some examples of Independent Scaffolds
http://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-22.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-22.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-22.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-22.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds-8.jpg


5/22


6/22


7/22


8/22


9/22

Suspended Scaffolds
http://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.pnghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.pnghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.pnghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.pnghttp://scaffmag.com/wp-content/uploads/2010/09/indy-scaffolds.jpg


10/22
http://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-9.jpg


11/22
http://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/suspended-scaffolds-5.jpg


12/22

Temp Roof Scaffolds
http://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-9.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-6.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-7.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-8.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-9.jpg


13/22
http://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-5.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-2.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-3.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-4.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-5.jpg


14/22
http://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-11.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-12.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-11.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-12.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-11.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-12.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-10.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-11.jpghttp://scaffmag.com/wp-content/uploads/2010/09/temp-roof-scaffold-12.jpg


15/22

Independent Tied Scaffolds

An independent scaffold consists of a double row of standards, with each rowparallel to the building. The inner row is set as close to the building as is

practicable. The distance between the lines of standards should be the

minimum necessary to accommodate the required number of boards and toe

boards.

A variation may be adopted in which the row of standards nearest to the

building can be set back about 300 mm from the building face. This means that

one of the boards of the platform can be laid between the inside row of the

standards and the building face.The standards should be connected with ledgers parallel to the building and

fixed with right angles couplers. Transoms are then fixed to the ledgers withputlog couplers to support the recommended platform widths.

Sole boards and base plates should be used under each standard as

recommended.

Ledger bracing is generally fixed to alternate pairs of standards.

Sway bracing is required at intervals not exceeding 30 M.

The scaffold should be tied into the building at the frequency recommended.

An independent scaffold consists of a double row of standards, with each row

parallel to the building. The inner row is set as close to the building as is

practicable. The distance between the lines of standards should be the

minimum necessary to accommodate the required number of boards and toeboards. A variation may be adopted in which the row of standards nearest tothe building can be set back about 300 mm from the building face. This means

that one of the boards of the platform can be laid between the inside row of the

standards and the building face.


16/22

The standards should be connected with ledgers parallel to the building andfixed with right angles couplers. Transoms are then fixed to the ledgers with

putlog couplers to support the recommended platform widths.

Sole boards and base plates should be used under each standard as

recommended.

Ledger bracing is generally fixed to alternate pairs of standards.

Sway bracing is required at intervals not exceeding 30 M.

The scaffold should be tied into the building at the frequency recommended.

Scaffold Towers


17/22

Free Standing TowersFree standing structures which are self-supporting and do not depend totally onother structures for their rigidity and stability. Three classes of these structures

are generally recognised.

1. Light Duty Access TowersStationary and mobile for use inside buildings (imposed load not greater than

1.5 kN/M2).

2. Light Duty Access TowersStationary and mobile for use in the open (imposed load not greater than 1.5

kN/M2).

3. Heavy Duty TowersThese are always built to design details.

Mobile Towers OnlyJoints in standards should only be made with sleeve or parallel couplers.Wheels or castors not less then 125 mm in diameter and fitted with brakes

which cannot be released accidentally should be locked into the base of

standards. The safe working load should be marked on the castor wheel.

AccessLadder should be fixed to narrowest side of the tower, preferable inside the

base area. It may be upright or angled. All usual ladder regulations apply.


18/22


19/22

Mobile and Static TowersDimensions will vary according to need, but standards should never be less

than 1.2 M or more than 2.7 M apart.

Foot ties should be fixed approximately 150 mm from the bottom of thestandards.

Except for the working platform, ledgers and transoms should be fixed to the

standards with right angle couplers.

Lifts should not exceed 2.7 M or be greater than the smallest base dimension.

Bracing is in two forms:

1. Plan bracing at the base, the working platform and at alternate lifts. 2.Diagonal bracing to the full height of the scaffold on all four sides.

Plan bracing should be fixed to the standards with right angle couplers.

Diagonal bracing should be fixed to the ledgers and transoms by right angle or

swivel couplers. The height to base ratio should not be greater than shown

below for each type of structure.

Stationary internal tower 4 to 1Stationary external tower 3.5 to 1

Mobile internal tower 3.5 to 1

Mobile external tower 3 to 1

The recommended maximum freestanding height for static towers is 10.8 M,except that this may be increased to 50 M if it is tied to a structure at 6 M

intervals.

The working platform should be fully and closely boarded to an area of at least

1.2 M x 1.2 M.

Transoms should be spaced at not more that 1.5 M intervals.A distributed load on the platform of a light duty tower should not exceed 1.5

kN/M2.

Guard rails and toe boards will be necessary on all four sides, and the toe

boards must rise at lease 150 mm above platform level. Guard rails must be at

least 950 mm above the platform width with the distance between the top of the

toe board and the guard rail not exceeding 470 mm.

Putlog ScaffoldsA putlog scaffold consists of a single row of standards, parallel to the face of

the building and set as far away from it as is necessary to accommodate a

platform of four or five boards wide, with the inner edge of the platform as

close to the wall as is practicable.

The standards are connected by a ledger fixed with right angle couplers and the

putlogs are fixed to the ledgers using putlog couplers.

The blade end of the putlog tube (or putlog adaptor) is normally placed

horizontally on the brickwork being built, taking care to use the maximum

bearing area.


20/22

Loadings and SpacingsGeneral PurposeMaximum Standard Spacing 2.1 M Maximum Loading 2.0 kNHeavy DutyMaximum Standard Spacing 2 M Maximum Loading 2.5 kN Average heightof lifts 1.35 M approx Max height 50 M (unless designed)Sole boards or base plates are usually fitted under each standard. The same

number of ties applies as for an independent tied scaffold. Reveal ties are not

recommended for putlog scaffolds.Where a putlog is required for an intermediate board support and it is opposite

an opening in the building, such as window or doorway, the inside end of theputlog should be supported on an underslung bridle tube spanning adjacent


21/22

putlogs. The bridle tube should be secured with right angle couplers.

Sway bracing is required at intervals not exceeding 30 M but, unlike

independent tied scaffolds, ledger bracing is not required in the finished

scaffold.

Roof SaddleGenerally agreed to mean the foundation for a scaffold erected on a pitched

roof, when chimneys are to be repairs. Roof saddles are generally erected when

minor repairs are made, e.g. replacing chimney pots, or repointing etc.

A safe means of access or egress must always be provided, and this will usually

comprise an access tower with walkway onto scaffold.

Roof Stack (illustrated below)

This type of scaffold, because of the position of the chimney, requires anaccess scaffold.

Roof stacks are erected where more substantial repairs are required i.e.

demonstration and/or rebuilding of chimney in situation where the stack is in

such a position as to make the erection of a saddle scaffold impracticable.

Roof SaddleGenerally agreed to mean the foundation for a scaffold erected on a pitched

roof, when chimneys are to be repairs. Roof saddles are generally erected whenminor repairs are made, e.g. replacing chimney pots, or repointing etc.

A safe means of access or egress must always be provided, and this will usually

comprise an access tower with walkway onto scaffold.

Roof Stack (illustrated below)This type of scaffold, because of the position of the chimney, requires an

access scaffold.

Roof stacks are erected where more substantial repairs are required i.e.

demonstration and/or rebuilding of chimney in situation where the stack is in

such a position as to make the erection of a saddle scaffold impracticable.


22/22

access birdcage scaffolds

Documents