TECHNICAL BULLETIN:02 Date: 13 Dec 00
The following has been extracted from the Code of Practice for Cranes
CRANE LIFTED WORK PLATFORMS (MAN CAGES)
A crane lifted platform is the piece of equipment from which employees carry out their work which is either attached to the crane's hook or the head of the crane's boom.
Conditions that apply to the use of a crane-suspended work platform are:
- All platforms shall be designed, manufactured and tested in accordance with NZS3404 (50% overload) or BS2573 (50% overload) or a standard which is acceptable to OSH.
- The platform is to be fitted with side walls or guardrails with midrails and toe-boards, or guardrails with any other suitable barrier such as expanded metal or chain mesh. The sidewalls or guardrails should be of a minimum height of 1 metre and be able to withstand, without obvious deflection, a horizontal force of 440 Newtons or a vertical force of 690 Newtons applied separately in any position.
- The floor of the platform shall be slip-resistant and free draining. Electrically insulated platforms need not be free draining, but can be fitted with an insulated insert complying with ANSI 92.2. Insulated buckets should be dried using sponge and bucket before use.
- Platform gates, where fitted, shall be able to be secured in position and open inwards or slide sideways and be self-closing.
- A safe means of access to the platform shall be provided. If access is by means of steps or a fixed ladder, the rise of steps or rungs shall be uniform and shall not exceed 300mm. The steps or rungs shall be slip-resistant.
- Machines designed for specific activities may have different platform and guardrail layouts provided an equivalent level of safety is afforded operators.
- All cranes being used for suspended work platform use shall have power lowering capability. Free fall capability should be "locked out".
- Cranes with automatically applied brakes to the hoist or twin lever operated hoists may operate with two hooks.
- Where a crane that is to be used has multiple hoist drums and is fitted with a hoist system that allows either hook block to free fall, the hook block not in use shall be removed and the wire rope stowed.
- Cranes operating swinging or fixed platforms shall operate within their safe working limits.
- All cranes being used with swinging platforms shall have Anti-two block devices fitted.
- When operating swinging work platforms from the hook, all hook safety latches shall be fully operational.
- When a work platform is suspended from a hook, the crane operator shall be in attendance at all times and shall operate the crane within the manufacturer's recommendations.
- The crane operator shall carry out appropriate inspections of equipment daily before use.
- Persons working on the platform shall wear the appropriate safety harness at all times. In the case of a platform suspended from the hook, all harnesses shall be independently attached to the hook. Where the platform has a roof or cover there shall be a harness anchor point incorporated in the structure under the roof.
- Appropriate personal protective equipment shall be worn at all times.
- Persons working from the platform shall be able to have appropriate communication with the crane operator at all times.