A suspended scaffold incorporates a suspended platform capable of being raised or lowered when in use. Other terms often used are ‘suspended cradle’ and ‘swing-stage’ scaffold. They are typically prefabricated modular units (see Figure 1) or permanently fabricated units although they can be assembled from scaffolding.
FIGURE 1 Suspended (swing-stage) scaffold – cradle (suspended) end
The electric Suspended platform is mainly used in the following aspects:
1.exterior maintenance and cleaning of high-rise buildings.
2.construction inspection and maintenance of big-size tanks,chimneys ,dams, bridges and derricks.
3.welding, cleaning and painting of big-size ship.
It is easy to operation,flexible for moving,reliable in safety.It can take the place of construction scaffolding,improve the efficiency and save cost.
|Platform Dimension L×W×H(mm)||(2.5m*3)*0.69m*1.18m||(2m*3)*0.69m*1.18m||(2.5m*3)*0.69m*1.18m||(2.5m*4)*0.69m*1.18m|
|Lifting Height||100 m/328ft||100 m/328ft||100 m/328ft||100 m/328ft|
|Cable||100 m/328ft||100 m/328ft||100 m/328ft||100 m/328ft|
|Steel rope||dia8.3mm 4*31SW+FC-8.3||dia8.3mm 4*31SW+FC-8.3||dia8.3/8.6mm 4*31SW+FC-8.3/8.6||dia8.3/8.6mm 4*31SW+FC-8.3/8.6|
|Safety lock||Permission force of impact||LSB30:30KN/LSD20:20KN||LSB30:30KN/LSD20:20KN||LSB30:30KN/LSD20:20KN||LSB30:30KN/LSD20:20KN|
|Locking Cable Angle||3°~8°||3°~8°||3°~8°||3°~8°|
|Suspension mechanism||Front beam overhang||1.15-1.7m/3.8-5.6ft||1.15-1.7m/3.8-5.6ft||1.15-1.7m/3.8-5.6ft||1.15-1.7m/3.8-5.6ft|
A suspended scaffold must be designed by a competent person and must be erected by a person holding an advanced scaffolding or advanced rigging high risk work licence. Operators do not require a licence but must be competent. Designer or manufacturer instructions should be followed when installing, erecting and operating a suspended scaffold.
Risk control measures that should be implemented for a suspended scaffold include:
providing safe entry to and exit from the cradle
consulting with and providing specific training and instruction for workers on the correct procedures for using and working on suspended scaffolds including instructions on safety features like:
the emergency stop, load limiting device and rope lock device
rescue or emergency evacuation devices or equipment
raising and lowering operations particularly in the event of an emergency
e.g. a power failure
developing and implementing a rescue and retrieval procedure before starting work including all necessary equipment, and
inspecting components for damage, wear and cracks before use and at pre-determined intervals. Non-destructive testing for cracks in high stress areas e.g. dye penetration testing may be needed to identify cracks not easily visible.
Example checklists for suspended (swing-stage) scaffolds are provided at Appendix A.
The suspension rig should be designed and documented by a competent person, for example a person who holds a tertiary qualification in a relevant engineering discipline.
Every area of design for a suspended scaffold system should receive a formal sign-off from a competent person. The formal sign-off for the suspended scaffold system should include the needle suspension system, cradle and hoist. Different parties may certify different components.
The scaffold configuration should be suitable for where the equipment is to be located
and how it is intended to be used. The scaffold designer should consider the following
to manage risks:
The building or structure to which the suspended scaffold is to be mounted should
be capable of supporting the scaffold and the intended loads including dead, live and environmental loads. The supporting structure should be assessed by an engineer and a statement of assessment provided.
A detailed design plan should be prepared for erecting each suspended scaffold taking into account the design specifications of the scaffold, the limitations of the support structure and maximum operational wind speed or lateral forces it may be exposed to during erection or operation.
Where structural alterations to the suspended scaffold are made, the changes should be recorded on an amended design plan. The designer or another competent person should review and approve the changes before the scaffold is used for the first time.
Damage can be caused to the cradle or hoisting systems if certain activities e.g. welding, water or pressure blasting or demolition activities are carried out without protective measures being in place.
To operate correctly, enough power should be available for electrically powered hoists— ensure the voltage drop is considered.
Lateral restraints may be provided to prevent instability of the platform e.g. resulting from the work procedures or wind and may include:
tensioned wire ropes
fan units, and
Note: Every restraint is to be removed when no longer required.
Suppliers should get and keep written confirmation of the following:
The suspended scaffold system has been designed in accordance with AS/NZS 1576.1: Scaffolding – General requirements and AS 1576.4: Scaffolding – Suspended scaffolding.
Couplers supplied for use with suspended scaffold have been designed, tested and marked in accordance with AS 1576.2: Scaffolding – Couplers and accessories.
Scaffold hoists have been designed, manufactured and tested in accordance with
AS 1418.2: Cranes (including hoists and winches) – Serial hoists and winches.
The supplier of the suspended scaffold must provide written operating and safe use
instructions and warning tags to users of the equipment. Daily safety checklists may
also be provided.
Suppliers should check that:
The design of the powered scaffolding hoists being supplied is a twin rope type—
a hoist with separate hoist rope and backup rope. Alternatively, a second hoist rope
with secondary protective device should be used.
Scaffold hoists and secondary protective devices have legible data plates bearing the following information:
type model identification
details of steel wire rope used including nominal size, grade i.e. quality, construction and maximum length where applicable
rated capacity hoisting
name or identification mark of the manufacturer of the hoist
reeving requirements where applicable, and
power supply requirements where applicable.
If the cradle is fitted with a power outlet e.g. for hand tools, it should have a residual current device (RCD) on the cradle with a legible data label bearing the following information:
rating load in amps
residual tripping current—not more than 30 mA, and
power supply in volts.
Hoist controls are labelled and unless the function is obvious, the operational functions displayed. Switches should be of the spring loaded ‘deadman’ or ‘hold to run’ type that returns to safe operation. Labels should include:
emergency stop switch, and
up and down control.
The control box is compatible with how the specific type and model of hoist operates. If multiple hoists are used, each hoist should have the same operating specifications.
Where a common control box is used for multiple hoists, it should be compatible with the hoists being used and be removable, unless an alternative method is used to isolate power to the cradle for safety and security when the suspended scaffold is not in service.
Each scaffold hoist’s secondary protective device and load-limiting device is inspected and subjected to an operational test in accordance with AS/NZS 4576: Guidelines for scaffolding before each site delivery.
Inspection and testing information is provided.
An electrically powered scaffold hoist is fitted with a load-limiting device that will prevent the hoist from lifting more than 125 percent of its rated load.
A secondary protective device, often incorporated into the hoist, is capable of stopping the cradle from falling if the hoist fails.
Between each hiring of scaffold equipment, scaffolding components are inspected and maintained, so far as is reasonably practicable.
Before being set up, a competent person must inspect and verify the structural adequacy
of the suspension system and the cradle. The manufacturer of the cradle and hoist should provide the structural verification and information on the maximum working load limit (WLL).
Scaffolders and operators should consider the areas around the suspended scaffold
during design, erection and operation. The following particular areas of concern should be considered and addressed before work to erect or operate the scaffold starts:
Where the scaffold is erected adjacent to or over public spaces or adjoining property specific controls like hoardings, catch platforms or barricades should be provided.
Where the possibility exists for other workers to enter the area below the suspended scaffold specific controls should be provided e.g. catch platforms, barricades or signs.
Overhead electric lines are a significant hazard and no part of the suspended scaffold including suspension and secondary ropes should be closer than 4 metres to an overhead electric line. When operating above electric lines and access to the cradle is provided above the power line this may be achieved by coiling the tail ropes to keep them above the power lines. Where operating from the ground, anchoring the ropes at ground level can prevent them from moving closer to the power lines.
Every electric line should be considered energised unless there is written confirmation from the Electricity Supply Authority that the electric lines have been de-energised for the duration of the work. Further information on erecting a scaffold near overhead electric lines is in the Information Sheet: Scaffolding work near overhead electric lines.
Protective measures should be provided to control the movement of vehicles near scaffolds and their trailing ropes and power cables.
Where cranes operate near a suspended scaffold, there is a risk of the load snagging the scaffold or endangering people on the platform. Specific site procedures should be developed to minimise the risk.
Where corrosive substances are to be used on the scaffold or in its vicinity, it may be necessary to develop specific procedures to minimise the risk of damage to critical scaffolding components.
The dangers presented by hazardous areas should be assessed before selecting equipment e.g. electric hoists should not be used where dust can form an explosive atmosphere.
The WLL should be clearly marked on the cradle of the suspended scaffold. The WLL of a cradle will depend on factors, for example its length, type of construction and material type. Materials loaded into the cradle should be evenly distributed and not be concentrated in one area.
To prevent overloading, swing-stage operators should verify the mass of the load to be carried by the cradle including people.
Note: On many long swing stages, the load capacity will be severely reduced and only minimal tools and equipment may be able to be carried.