Ensuring Safety in Critical Lifts: Best Practices for Rigging, Inspection, and Maintenance

Critical lifts represent some of the highest-risk activities in major construction projects, challenging both equipment and crane operators. According to BC Crane Safety (2024), a critical lift is defined as any lift that exceeds 90% of the crane’s rated capacity when the load radius is over 50% of the maximum permitted load radius. It also includes tandem lifts, lifts involving people on working platforms, changes in the center of gravity, variations in sling leg length during the lift, lifts on floating bases that exceed 90% of rated capacity, lifts near energized electrical conductors, and submerged loads.

Beyond this definition, the industry recognizes additional criteria for critical lifts. These may involve lifting over process equipment, working in congested areas, capacity concerns, or even specific placement requirements.

Recent reports highlight the critical nature of these operations. For instance, The Canadian Press noted a fourth crane incident within the first quarter of 2024. Although each incident had unique aspects, common failure points include:

  • Improper Training
  • Rigging Issues
  • Wires and Sheave Systems
  • Mishandling
  • Insufficient Maintenance

Nortech provides our customers with industry leading knowledge, competency training programs, and have a diverse range of NDE methods to support various forms of inspections.

Rigging

Rigging is essential for securing loads during lifting activities, directly impacting safety and operational success. Human error is a major cause of rigging accidents, which can stem from:

  • Ignorance of load weights or sling capacities
  • Inadequate load security, lifting points, or sling protection
  • Poor pre-use inspections
  • Insufficient training

Rigging can be inspected through a variety of techniques, from visual inspection, service tests to non-destructive testing. The personnel conducting these inspections shall be trained in the appropriate inspection technique and potential defects.

A recurring theme throughout this discussion is the importance of pre-use inspections and proper training.

Wires and Sheave Systems

Wire ropes and their sheave systems are critical to lifting operations. The interaction between the sheave and wire rope affects their performance and lifespan. Neglecting sheave maintenance can lead to premature wire rope failure, posing safety and operational risks.

Common issues with sheave systems include inadequate lubrication, which accelerates wear on both the wire rope and components. Recently, the adoption of composite sheaves has mitigated external wear but introduced challenges with internal wire rope breakage. Early detection of such flaws is crucial.

Visual inspections are vital for monitoring wire ropes and sheave systems. Equipment should be taken out of service if any of the following issues are detected:

  • Broken wires
  • Diameter reduction
  • Excessive corrosion
  • Rope deformation
  • Heat damage
  • Sheave lubrication system damage
  • Sheave slack
  • Misalignment
  • Excessive sheave wear

Non-Destructive Testing (NDT) methods complement visual inspections. Magnetic Flux Leakage (MFL) detects magnetic leakage lines with strong magnets and sensors, effective for identifying wire rope damage. Digital radiography provides detailed images of rope sections but lacks comprehensive coverage. Employing both visual and NDT methods helps ensure early detection and resolution of issues, enhancing safety and equipment reliability.

Mishandling

Mishandling of lifting equipment, especially cranes, is a significant contributor to equipment failure and safety risks. This issue includes operator mistakes and improper storage practices, which can lead to:

  • Mechanical damage from improper load handling
  • Component degradation due to corrosion or neglect

Proper training is essential to mitigate mishandling risks. Personnel should be trained to identify and address issues before they escalate. If cranes experience shock loads or visible damage, affected parts should be removed from service immediately for thorough inspections.

Magnetic Particle Inspection (MPI) is useful for detecting surface and subsurface defects in coated components, while Shear Wave Ultrasonics identifies internal flaws in hard-to-reach areas. These inspection techniques, combined with rigorous training and maintenance, are crucial for enhancing safety and preventing mishandling-related failures.

Improper Maintenance

Maintenance is critical for safe and effective lifting operations, though it can be costly. As noted, many issues stem from insufficient inspection and maintenance. Maintenance practices vary across North America, but the underlying principle of due diligence remains constant.

Maintenance tasks include greasing cables, pulleys, and bearings, and inspecting critical structural components. Thorough inspections by skilled technicians can prevent downtime and potentially save lives.

In summary, ensuring the safety and reliability of lifting operations requires rigorous attention to training, inspections, rigging, maintenance, and the use of advanced testing methods. By addressing these factors proactively, you can significantly enhance operational safety and efficiency. Utilizing competent and trained crane and structural certification organizations can help significantly reduce your risk.

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