Using a workbox or man cage
A workbox is designed to be supported by a crane, hoist, forklift truck or other mechanical device to provide an elevated work area for persons working from the box. It consists of a platform surrounded by an edge protection system and should be designed in accordance with AS 1481:17 Cranes (including hoists and winches) – Design and construction of workboxes.
Where reasonably practicable, other working platforms, such as an elevating working platform or scaffold, should be used as an alternative to the workbox.
The safety requirements and considerations include that:
- the workbox is not suspended over persons
- the workbox is designed for the task and securely attached to the crane. The workbox, lifting attachments and records should be checked by a competent person before use
- the workbox is fitted with suitable anchorage capable of withstanding the fall forces specified in AS/NZS 1891.4 Industrial fall-arrest systems and devices – Selection, use and maintenance. Workers must be attached to the anchorage by a lanyard and harness unless the workbox if fully enclosed
- workers remaining within the workbox while they are being lifted or suspended
- workers do not enter or leave the workbox when it is suspended (except in emergency)
- the crane if fitted with the means to safely lower it in an emergency or a power supply failure
- the crane is suitably stabilised at all times while the workbox is used
- the crane has “drive up” and “drive down” control on both the hoisting and luffing motions and those controls are used. No declutching allowing free fall is to be used while a workbox is in use
- an effective means of communication between any person in the workbox and the operator is provided
- the crane is fitted with a safety hook and moused (lashed) accordingly
- the operator remains at the controls of the crane at all times
For specifications for the use of crane workboxes refer to AS 2550.1 Cranes, Hoists and Winches—Safe Use—General Requirements.
Forklifts with a workbox
A workbox fitted to a forklift must be securely attached to the forklift carriage and engineer-designed and constructed in accordance with AS 2359 Powered industrial trucks
Safety considerations include that:
- people are not raised on the tynes of forklift trucks or the pallet
- no other device (for example, ladder or pallets) is used to gain additional height (see Figures 13 and 14)
- the safety gate is self-locking and kept shut when in the elevated position.
BUILDING MAINTENANCE UNITS
Designers of buildings should consider the methods by which maintenance, repairs or cleaning will be undertaken on buildings or structures.
A building maintenance unit is a power-operated suspended working platform that is fixed permanently to a building or structure. It is used for access for building maintenance or window cleaning (see Figure 15).
Safety considerations include that:
- the platform has sufficient, clearly designated safety harness anchorage points designed to withstand the forces by a fall of any person anywhere on the platform
- the units are designed in accordance with AS 1481.13 Cranes (including hoists and winches) Building Maintenance Units and operated by a competent person in accordance with AS 2550.13 Cranes – Safe Use – Building Maintenance Units