Background

WorkSafe Victoria has investigated several incidents where crane components have failed. If the cranes had been suspending personnel in workboxes at the time of these failures, the incidents could have resulted in the serious injury or death of the personnel.

Minimum standards for cranes to suspend workboxes

Only cranes that comply with the requirements of Australian Standard AS 2550.1 – 2011 Cranes, hoists and winches – Safe use, Part 1: General requirements, clause 6.19 'Suspension of persons by crane' should be used to lift personnel in a workbox.

With respect to the braking design of the crane it shall comply with AS 1418.1 – 2002 Cranes, hoists and winches, Part 1: General requirements, clause 7.12 'Braking' and it has:

  1. at least two brakes, independent of each other where failure of a brake or any single component in the brake – drive train will not result in loss of control of the load, or
  2. a brake acting directly on the hoist drum and a hoisting mechanism or other brake capable of holding the load when not under power.

Note: For cranes that utilise a luffing hoist the above shall also apply for the luffing hoist.

Crane brake design

Where the crane design complies with the requirements of having two independent brakes configured so that the failure of a brake or single component in a drive train will not result in loss of control of the load the requirements of clause 7.12.8.3 shall apply.

Where this is not the case the crane should be modified to comply with (i) above or clause 7.12.8.5 of Australian Standard AS 1418.1 – 2002 shall apply.

Clause 7.12.8.5 'Special lifting applications' of Australian Standard AS 1418.1 – 2002 Cranes, hoist and winches, Part 1: General requirements, stipulates that for special lifting applications where the loss of one component of the hoist drive train will result in loss of control of the workbox, an additional brake must be fitted to the hoist drum that complies with clause 7.12.8.3 'Multiple brake hoists'.

WorkSafe advises that:

  • Where a crane has not been specifically designed for lifting personnel, such as mobile and tower cranes, the lifting of personnel in a workbox is considered to be a special lifting application.
  • Where there is either a coupling, spline, clutch, gearing or other non-rigid connection between a brake and the hoist drum, this brake is not considered to be 'fitted to the hoist drum' and an additional brake, fitted to the hoist drum through a rigid mechanical connection, must be installed.
  • Where the crane incorporates a single brake fitted to the hoist drum and relies on the braking system of the drive train to act as a secondary brake, the pre-testing requirements identified in the maintenance and monitoring requirements below shall be complied with.
  • To fully comply with the requirements of clause 7.12.8.5, the further requirements of automatic overspeed control; emergency stop function and utilisation coefficient must be complied with.

Note: For cranes that utilise a luffing hoist the above shall also apply for the luffing hoist.

Condition of the crane

All cranes that are to be used to lift personnel should have full service records. A crane greater than 10 years old that has not undergone a 10-year inspection in accordance with the requirements of Australian Standard AS 2550.1 should not be used to lift personnel in a workbox.

A crane that has suffered damage or been overloaded and has not then been subjected to a 10-year major inspection should not be used to lift personnel.

Maintenance and monitoring requirements

Where a crane utilises a single brake acting directly on the drum, confirmation of the braking efficiency of the hoisting drive train shall be confirmed.

Confirmation of the braking efficiency shall as a minimum incorporate the following requirements.

Before commencing the lift of personnel, the crane shall hoist and hold a load:

  1. equivalent to the line pull of the hoist winch, or
  2. at least 200% of the maximum hoisted load as defined in clause 1.4.3 of AS 1418.17.

In either case the crane shall hoist and hold a load that is not less than 200% of the maximum hoisted load as defined in clause 1.4.3 of AS 1418.17.

With the load stationary all power and hydraulic/pneumatic power shall be released and the brake 'backed-off' or isolated to the extent it no longer applies a restraining force.

The load shall then be monitored for movement or creep. The drive train shall be considered to be a satisfactory braking system if no movement or creep is detected over a 5-minute testing period.

Note:

  1. Where the crane is used to lift loads other than the workbox, the above test shall be repeated prior to re-lifting the workbox.
  2. During operation of the crane with a workbox, the line pull of the hoist winch shall not exceed that used in the above test.

Further information

  • AS 2550.1 – 2011 Cranes, hoists and winches, Safe use, Part 1: General requirements, clause 6.19 'Suspension of persons by crane'
  • AS 1418.1 – 2002 Cranes, hoists and winches, Part 1: General requirements, clause 7.12 'Braking'
  • AS 1418.1 – 2002 Cranes, hoists and winches Part 1: General requirements, clause 7.12.8.3 'Multiple brake hoists'
  • AS 1418.1 – 2002 Cranes, hoists and winches, Part 1: General requirements, clause 7.12.8.5 'Special lifting applications'