National Commission for the Certification of Crane Operators (NCCCO) Mobile Crane Practice Exam

By what percentage do most manufacturers require a crane's load chart capacity to be reduced for duty cycle operations such as high-volume concrete placement?

1. 10%

2. 15%

3. 20%

4. 30%

The correct answer is: 20%

Most manufacturers require a crane's load chart capacity to be reduced by 20% for duty cycle operations like high-volume concrete placement. This reduction is necessary due to the dynamic nature of such operations, which can involve constant movement and repositioning of the crane, leading to increased stresses on the equipment. The added factors of material weight, potential vibrations, and the extended time a load may remain on the hook necessitate this precaution to ensure safety and maintain operational integrity. By adhering to this guideline, operators can account for the additional forces at play during these types of lifting operations, thus preventing possible overload scenarios that could result in equipment failure or accidents.