In this guide, we will be providing information on specific kinds of scaffolds and scaffolding. In addition, will provide practical examples that show how to control some of the common risks that are associated with using scaffolding. This guide belongs to a larger series of guidance materials so can be considered a basic guide in itself. Ideally, it should be read and used together along with the general guidelines for scaffolding work as well as scaffolds. That includes risk management information and advice on planning, altering, erecting, dismantling, as well as working with scaffolding, along with measures that help to control risk that is discussed in this guide.
With this in mind, let’s take a look now at the various types of scaffolds and scaffolding.
Birdcage Scaffold Guide
This is an independent type of scaffold that is comprised of over 2 rows of standards in both directions that are connected by ledgers and transoms. The birdcage scaffold is mainly used for work being done on a ceiling or other single level. It is very important to consult with the specifications from the designer or manufacturer when a birdcage scaffold is being erected or dismantled that is made out of modular scaffolding.
The following risk control measures should be implemented for birdcage scaffolding that is made out of coupler and tube scaffolding.
- Only use birdcage scaffolding for supporting framework if it was specifically designed for that purpose.
- Transverse bracing should be provided on the scaffold ends at each forth bay.
- Brace the standards’ outer row on each face and also each third row internal by using longitudinal bracing.
- Provide a longitudinal bracing or tiered face at each third longitudinal standards row.
- Consider utilising elevated work platform to help with erecting or dismantling birdcage scaffolds.
Usually, fall arrest systems are not the best risk control measure when erecting or dismantling perimeter or birdcage scaffolds.
Trestle Scaffold Guide
This type of scaffold is assembled out of prefabricated accessories, trestles, and braces. Trestle scaffolds, including H-frame and A-frame trestle scaffolds, typically are used by bricklayers, plasterers, painters, and general finishing and fit-out projects. For erecting or dismantling a trestle scaffold, usually, a licensed scaffolder is not required.
However, only a competent individual should dismantle or erect a trestle scaffold. It should be done in a progressive manner to ensure the installer’s safety along with the entire structure’s stability. To attach the braces to trestles, the instructions provided by the manufacturer or supplier should be followed.
As the trestle’s height continues to increase, there is a greater need to provide the trestles with lateral stability. An appropriate foundation should be used to erect a trestle scaffold on, and it should be stable enough to ensure that it can safely distribute and carry loads such as materials and workers on each of the trestles. Measures to stop possible toppling and control instability include using ties or outriggers on a permanent structure.
A trestle scaffolds also should be able to:
- Support the relevant load or duty rating without exceeding them.
Note: The full width of the trestle ideally should be planked irrespective of what the duty rating is.
- Have barriers or edge protection installed where any potential fall might result in the individuals who are using the scaffold becoming injured or if there are hazards contained in the fall rea such as reinforcing bars or other sharp objects.
- Have a way to load material safely on the working platform. This could include using a mechanical means or in areas where that is not practical, passing materials to the working platform instead of throwing it up.
- Have a horizontal work platform at least 4.5m wide. On sloping or uneven ground, a trestle should be used that has height adjustment provisions. Bricks or blocks should not be utilised as soleplates.
- Uniform scaffolding planks in serviceable condition i.e. no knots, bends, splits, or cracks, that overhang the end supports 1.5 to 2.5m that are secured against uplift.
- Not used by multiple individuals simultaneously in restricted work areas so that overloading is avoided. 2-plank, 4.5m platforms.
- Have a safe entry and exit i.e. secured ladders or by way of a building if the platform level is the same approximately as the building.
Most bracing systems used on tubular trestle scaffolds are made out of light materials that can be damaged easily by misuse or abuse. That is why great care needs to be taken during the assembling and dismantling processes. Under no circumstances should anyone climb the braces or trestles. Edge protection requirements are not satisfied by cross-braces that are part of trestle scaffolding.
Hung Scaffold Guide
A hanging scaffold or hung scaffold is a type of independent scaffold. They hang from a separate structure but are incapable of being raised or lowered while they are being used.
For a hung scaffold, consider implementing the following control measures:
- The scaffolding plan needs to provide information on the position of the check couplers.
- The hanging scaffold should be designed by a competent person and verification should be obtained to ensure that the structure that is being used to support the hanging scaffold is able to bear the entire design load.
- If you are planning to use a cantilevered suspension rig, there should be information provided to show how to build the rig and secure it.
- Standards on a hanging scaffold must be bolted or spliced with rated spigot connections based on the instructions from the manufacturer.
- Each of the vertical hanging tubes needs to have check couplers at the suspension points and under the platform according to the manufacturer’s specifications.
Single Pole Scaffold Guide
This type of scaffold is comprised of one row of standards connected by ledgers. Then putlogs are fixed to the ledgers and also built into the building wall or structures. This kind of scaffold will depend on the structure it is placed against for support. It is very important to make sure that none of the single pole scaffold components is removed before it is dismantled.
Suspended (Swing Stage) Scaffold
A suspended platform is incorporated by this type of scaffold that can be raised or lowered when in use. A great example of a suspended scaffold is a swing-stage scaffold.
Tower and Mobile Scaffolds
A tower scaffold is a type of independent scaffold comprised of 4 vertical standards that are connected longitudinally and transversely or 2 frames. These are connected transversely that results in a one-bay scaffold being created. A mobile scaffold is a type of tower scaffold that is mounted on wheels.
Scaffolds used for Demolition Work
Heavy duty or special scaffold, at a bare minimum, should be used in the demolition process, to provide edge protection and a safe working platform as well as to contain dislodged materials.
Factors that might affect a scaffold’s stability for demolition work include the following:
- Wind forces acting on containment sheet on the scaffold’s face
- The load that the demolished material imposes that is dislodged onto the scaffold
- Removal of ties and the scaffold’s progressive dismantling
- Retention of water within the containment sheeting caused by capillary action
- Progressive removal of the building’s elements that affect the lateral stability of the upper portion of the scaffold
- The following risk control measures should be implemented whenever scaffolds are used for demolition work:
- The scaffold planks must be secured to avoid them becoming dislodged due to falling debris
- The scaffold should be regularly inspected and maintained
- Ensure that the scaffold is dismantled progressively and in alignment with the demolition work that is being done
- To facilitate the demolition process, vertical spacing on the scaffold ties might need to be reduced.
- Install containment sheeting on the internal face of the scaffold to defect material into the building to reduce the potential of the scaffold becoming overloaded.
Special Duty Scaffolds Guide
This type of scaffold has a specific design load for a particular scaffold. These scaffolds differ from other types of scaffold working platforms with typical heavy duty, medium or light ratings. They have a maximum load rating and standardised minimum dimensions.
The following are common special duty scaffold examples:
- Cantilever Scaffold
- Cantilevered load-bearing members support this type of scaffold.
The following risk control measures should be implemented when using a cantilevered scaffold:
- Ensure that a competent person certifies the supporting structure as being able to support the cantilevered scaffold.
- Position and design the cantilever beams based on the engineer’s requirements and according to your scaffolding plan.
The following methods should be used for fixing the inboard length of the cantilevered beam to the structure:
- Use counterweights on the beam.
- Use a positive fixing like a U-bold fitted above the beam and then through the concrete floor slab so that the beam is fixed to the floor.
- Install props on the top of the beam and the underside part of the floor above. Ensure that the props are fixed so that dislodgement is prevented.
Hanging Bracket Scaffold
This type of scaffold is a system that receives support from a frame on a structure or building. Sometimes it is in an upside down L shape, where one arm is attached to a vertical surface and the other is protruding horizontally in order to provide the scaffold planks with support. Other types of hanging bracket scaffold systems might include horizontal embers supported by structures such as building floors.
For hanging bracket scaffolds it is very important that the following risk control measures be implemented:
- Hanging scaffolds, as well as their means of support, should be designed by an engineer. Engineering verification can be provided by calculations or load testing.
- Provide a way to enter for those who are installing the hanging brackets.
- On straight runs on a hanging bracket, scaffold planks may overlap planks where achieving butting of the planks is impossible as long as it is not less than a 3m overlap.
- The supporting structure must be able to support dead and live loads that are supplied by the hanging brackets.
- Connectors should be used if two scaffolds are more are sagging in an uneven way to cause a tripping hazard.
- Ensure that the bracket’s spacing doesn’t exceed the maximum amount of plank spans that the manufacturer has specified.
Note: that does not refer to planks overlapped on putlogs.
Inclined load-bearing members support this type of scaffold. For spur scaffolds, you need to implement the following control measures:
- Ensure that the propping systems are braced and tied together securely.
- To distribute the imposed loads, offer suitable headstocks on top of each propping system.
- Fix propping systems in between the floor and ceiling at intervals suited for the spacing of standards inside the scaffold.
- Brace spurs that are over 1.8m long in either direction at the centre unless designed otherwise.
Coupler and Tube Scaffolding
This type of scaffolding is built out of tubing and joined or fixed components that are attached to together to create the scaffold design that is desired. This type of scaffolding is frequently used on structures that have an unusual function, design, or shape. The versatility of this kind of scaffolding means it may be assembled in different configurations. This also means that it can be more complex to erect this type of scaffold than a prefabricated one. The load that coupler and tuber scaffolding are able to carry is determined by the strength and diameter of the tube in addition to the components that are used. If plain steel tubes are incorporated into a scaffold, the design and analysis must take the most adverse combination of the tubes by wall thickness or strength of the tube material or both into consideration. One scaffold should never mix steel and aluminium tubes. Tubes that have different wall thicknesses should not be interconnected using end-to-end internal-type spigots or couplers unless there are additional measures taken to secure the joint.
For example, a short tube with swivel couplers may be fixed parallel to and over the joint. Or a bridle can be fixed with right-angled couplers to the adjacent members. Metal coupler and tube components need to be inspected on a regular basis for damage. There should be special attention paid to corrosion, splitting, crushing, deformation, and cracks.
This type of scaffolding is an integrated system made of prefabricated components that have a predetermined geometry of an assembled scaffold. This type of scaffolding can include hung, tower, modular, cantilever, and suspended/swing-stage scaffolds. It is required for Prefabricated scaffolding to be designed registered according to the requirements under WHS regulations Schedule 5, Part 1.
If you are looking for knowledgeable and experienced scaffolders, who have leading-hands that work together with you and offer expert advice, please contact us at Skelscaff today on 1300 266 607 or email us at firstname.lastname@example.org.