U.S. requirements for suspended manned working platforms of cranes

The use of cranes or jib cranes to lift personnel will bring great danger to the employees being lifted. In order to avoid casualties, OSHA regulations (Federal Regulations, Title 29, 1926.550) restrict the use of cranes in the construction industry to lift personnel, and stipulate the safety measures taken for such operations.

The regulations of the Occupational Safety and Health Administration for lifting personnel are written in instructional language, requiring employers to provide the best protection for lifting personnel to avoid danger in the lifting operation, and to ensure that the lifting personnel arrive safely under the premise of complying with relevant requirements and standards. destination. OSHA regulations prohibit the use of cranes or jib cranes to lift personnel unless there is no other safer option.

1. General requirements for manned lifting devices and components

1) Load and safety factor. The safety factor of the steel wire rope used for lifting personnel shall not be lower than 7. The safety factor of the steel wire rope used for anti-rotation must not be less than 10. When the manned platform is in a static position, all braking and locking devices of the crane or jib crane must be set to a locked state. The total load weight of the manned platform and its transmission device shall not exceed 50% of the rated load of the crane or jib crane and device. The load of the manned platform shall not exceed its rated load capacity or bearing capacity. Only the personnel required to complete the task (tools, equipment and materials required for the work) are allowed on the manned platform. Materials and tools must be safe, and load balance should be maintained even when the platform is moving.

2) Protection device. Cranes with variable boom angles must be equipped with a boom angle indicator visible to the operator. Telescopic boom cranes must be equipped with a device that can clearly indicate the extension length of the boom, or the loading radius used for lifting must be accurately determined before the lifter. Cranes and jib cranes must also be equipped with a set of over-rolling protection devices to avoid contact between the movable pulley and the end of the boom, or the over-rolling protection devices should stop lifting before the danger occurs.

3) Manned platform. The platform used for lifting personnel must have a safety factor of not less than 5 and be designed by a qualified engineer or a person capable of structural design. The suspended platform should be designed with the smallest inclination to prevent the personnel on the platform from losing stability. A standard guardrail system must be provided for each manned platform, from the bottom guard plate to the middle fence should be guarded to prevent tools, materials or equipment from falling. This platform must have a built-in life-saving grab line and provide sufficient protection space for employees. The nameplate or other permanent mark is used to clearly indicate the weight and rated load capacity or maximum load-bearing capacity of the platform. In order to prevent objects from falling in the air, the platform needs to be protected in space, and relevant personnel must wear safety helmets.

If there is a safety door for entry and exit, it must not swing outward when ascending, and there must be a control device to prevent it from accidentally opening. All rough and sharp edges and corners of the platform should be polished smoothly to avoid personal injury. All welds and components of the manned platform must be completed by qualified welders, who must be familiar with the strength, type and materials of welding specified in the platform design.

4) Rigging. When using a wire rope as the upper halter to connect the platform and the hoisting rope, the halter bracket must be connected or tied to the main hoisting rope so that the load can be distributed in the upper halter bracket steadily. The upper halter and accessories connecting the working platform to the main hoisting rope shall not be used for any other purpose. Assembled accessories, such as hooks, must be closed and locked to prevent the opening of the hook from opening. For example, alloy anchor shackles with screws, nuts and fixing nails should be used. Tangle knots (wrap the wire rope around the hook and cover the hook opening) are not allowed.

2. Inspection and testing

Cranes and jib cranes used to lift personnel must be installed on a solid foundation, and cranes or jib cranes must be installed on a horizontal surface with an inclination of less than one hundredth.

Before the employees move up or down, they must carry out an unmanned lift test. In the trial lift test, a weight not less than the expected lift load must be placed on the manned platform. Lifting must start at ground level or where employees will enter the platform, and pass through various locations where the manned platform will be lifted or placed. The trial promotion test must be completed at the moment before the personnel are loaded onto the platform.

1) The operator of the crane or jib crane must check all systems, controls and safety devices to ensure that: functions are normal; barrier-free exists; all lifting arms or lifting loads that are allowed to reach the work site are allowed to operate to maintain a limited lift Within 50% of the rated capacity. If the crane or jib crane is moved to a new location, or other operations have been performed, a trial lift test must be performed again before manned lifting. After the trial lift test, the manned platform should be raised a few inches and checked to ensure that it is in a safe condition.

2) Before lifting personnel, check must be performed to ensure: check that the lifting ropes are not knotted; check that the ropes of each part are not entangled with each other; check that the main accessory device has been placed in the middle of the platform; check that there is no slack part in the rope; check that the ropes are all It has been firmly placed on the rope groove of the lifting pulley.

After the lift-up test, professionals should promptly conduct a comprehensive surface inspection of the crane, the manned platform, and the support or ground on which the crane is placed, to determine whether the lift-up test has found any safety hazards that may affect all components or structures. The hidden safety hazards discovered during the inspection must be eliminated before the lifting personnel.

If the platform and the conveying device enter the construction site for the first time or after repairing or eliminating hidden dangers, they must pass the 125% load-bearing test of the platform's rated load capacity before lifting the personnel. It can be verified by keeping the load platform (where the load is evenly distributed) in the suspended position for 5 minutes. Then a competent person must check the platform and the conveyor for omissions. If a problem is found, repair it immediately and perform another test. Manned lifting is not allowed until it is proved that the test requirements have not been fully passed.

3. Lifting operation

When the crane engine is started and the manned platform is used, it must be controlled by the operator. The movement of the manned platform must be cautious and slow, and no sudden acceleration of the crane, jib crane or platform is allowed.

1) Meeting before lifting. Before carrying out personnel lifting operations, the employer shall hold a meeting with all employees involved in manned lifting operations (including crane or jib crane operators, signal personnel, employees being lifted and personnel responsible for lifting operations) and review whether they are in compliance with occupational safety And health management requirements and procedures. This meeting should be held before the test promotion at each new construction site. For any personnel assigned to participate in this operation for the first time, such a meeting should be held again.

2) Safe operation. When employees perform personnel lifting operations, they must abide by the following safety operating guidelines:

①Use seat belts, unless the use of seat belts will lead to more unsafe conditions;

② Keep all parts of the body inside the elevator platform when ascending, descending and stagnating;

③Ensure that the lifting platform is in a safe state before entering and exiting the structure for operations, unless such protective actions will lead to unsafe conditions;

④ Put on a body harness or a full body protection device with a lanyard. A full set of body protection devices must be attached to lower load pulleys or loose steel cables or structural parts inside the manned platform.

⑤The carried personnel are in a position where they can be seen and can directly communicate with the operator or signal personnel.

3) Operators of cranes and jib cranes must comply with the following safe operation guidelines:

① When the crane or jib crane engine is started or when the platform is in use, continuous control must be maintained;

②If there are any dangerous weather conditions or possible dangerous situations, stop all lifting operations;

③When the crane or jib crane is used for manned lifting, it is not allowed to lift any other load.

4. Movement of the crane

It is forbidden to carry people when the crane is in a moving position, unless the employer proves that this is the least dangerous way to complete the task, or uses a portal crane, tower crane or truck crane.

If the crane moves during the lifting and lowering of people, it must comply with the following requirements: it must be restricted to move on a fixed track or runway; the movement must also be restricted to the radius of the boom during the ascent; the boom must be in line with the moving The directions are parallel; a comprehensive operation test must be carried out before the platform is loaded with people; if the crane uses rubber tires, the condition and air pressure of the tires must be checked, and the specified load-bearing capacity must meet the 50% of the rated load capacity that can maintain the rise limit. If required for movement, the cantilever support can be partially retracted.

During manned lifting operations, the general requirements of occupational safety and health management regulations should be observed, and it was determined that there is no safer way to choose to minimize or avoid possible casualties.

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