What Defines a Critical Lift with a Crane?

When it comes to crane operations, safety is of utmost importance.

One key aspect of crane safety is understanding what constitutes a critical lift. In this blog post, we will explore what defines a critical lift with a knuckle boom crane and the precautions that need to be taken.

Understanding Critical Lifts…

A critical lift refers to a rigging activity that requires planning and additional safety measures to minimize the risk of crane failure or accidents [1].

It typically involves lifts that exceed certain thresholds in terms of load capacity, lift configuration, or proximity to hazardous areas.

Load Capacity Thresholds

Different sources provide varying percentages for load capacity thresholds that define a critical lift. For example, one source mentions that a critical lift occurs when the load being lifted exceeds 90% of the rated capacity of the mobile crane or boom truck [2].

Another source states that any lift exceeding 80% of the crane’s rated capacity within its specific configuration can be considered critical [4].

It’s important to consult industry-specific guidelines and provincial regulations for accurate information on load capacity thresholds pertaining to knuckle boom cranes in your province.

Lift Configuration and Proximity

Apart from load capacity, other factors related to lift configuration and proximity may also define a critical lift:

1. **Boom Length**: A critical lift can occur if the length of the boom used for lifting exceeds certain limits specified by manufacturers or industry standards.
2. **Boom Angle**: The angle at which the boom is positioned during lifting plays a crucial role in determining whether it falls under the category of a critical lift.
3. **Work Area**: If any part of the knuckle boom crane’s boom or attachment operates within close proximity (e.g., within 6 meters or 20 feet) of hydrocarbon or pressurized piping areas, it may be considered a critical lift [5].

Precautions and Safety Measures

Performing critical lifts with ‘knuckle boom’ cranes requires detailed planning and full adherence to safety protocols. Here are some precautions that should be taken:

1. **Comprehensive Planning**: Before undertaking a critical lift, a detailed plan should be developed, considering factors such as load weight, rigging techniques, lift configuration, and potential hazards.
2. **Additional Safety Measures**: Critical lifts often necessitate additional safety precautions beyond standard lifting operations. These measures may include using specialized rigging equipment, employing multiple cranes for tandem lifts, or implementing enhanced communication systems.
3. **Qualified Personnel**: Only trained and certified crane operators and riggers should be involved in critical lift operations.
4. **Regular Inspections**: Regular inspections of the knuckle boom crane should be conducted to ensure its optimal condition and identify any potential issues that could compromise safety.


In summary, a critical lift with a ‘knuckle boom’ crane, any crane to be forthright, is defined by various factors such as load capacity thresholds, lift configuration parameters (boom length and angle), and proximity to hazardous areas, environmental, ground conditions, operator skillset, tandem crane lift, unknown load, unbalanced load, etc.

To ensure safe operations during critical lifts, comprehensive planning, additional safety measures, qualified personnel, and regular inspections are essential.

Remember to consult industry-specific guidelines and regulations for accurate information on critical lifts with knuckle boom cranes in your region.

Lift safe!

*Note: The images used in this blog post are for illustrative purposes only.*

1. R. Baker & Son – What is a Critical Lift? 
2. BC Crane Safety – Critical Lifts
3. US Army Corps of Engineers – EM 385-1-1
4. SafetyInfo – Workplace Safety Program
5. HSSE World – Critical Lifts
6. Astro Crane – What is Meant by a Critical Lift?

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