Sling Angles and Lifting Capacity
The Problem
When using two or more slings to lift a load, many workers overlook the critical impact of sling angles on lifting capacity. A poorly chosen angle can overload slings, lead to sling failure, and cause catastrophic accidents. Today, we’ll discuss how sling angles affect lifting capacity and the steps we can take to ensure safe and proper rigging operations.
Identify the Hazards
Safety Practices and Preventative Measures
Understand How Sling Angles Impact Capacity
- Flatter angles = more load on each sling leg = reduced lifting capacity.
Examples of Capacity Reductions:
- 1,000 kg capacity at a 0-degree angle (horizontal)
- 866 kg at a 15-degree angle
- 707 kg at a 30-degree angle
- 500 kg at a 45-degree angle
Best Practices for Sling Angles:
- Optimal Angle: Use a sling angle of 60 degrees or greater from the horizontal plane.
- Why 60 Degrees?: It provides a balance between lifting strength and reduced tension on the slings.
- Effects of Shorter Slings: Shorter slings result in lower sling angles and increased load on the sling legs.
- Choker Hitches: Similar angle effects apply; improper angles can significantly reduce capacity.
Involve a Competent Person in Rigging Operations
- A competent person must oversee all rigging and lifting activities.
- Always follow the sling manufacturer’s specifications and ensure sling angles are within recommended safe limits.
Real-Life Case or Scenario
On a recent worksite, a crew attempted to lift a 2,000 kg load using two slings set at a 30-degree angle. The sling capacity was significantly reduced, and one sling failed under tension, causing the load to fall. Fortunately, no one was injured, but the incident highlighted the importance of correct sling angles and proper planning. Had a 60-degree angle been used and a competent person reviewed the lift, the failure could have been avoided.
Employee Responsibilities
Before the Lift:
- Inspect slings and verify rated capacities.
- Calculate sling angles and confirm suitability.
During the Lift:
- Monitor sling angles throughout the lift.
- Stop the lift if any part of the setup looks unsafe.
Report Hazards:
- Notify a supervisor or competent person immediately of damaged equipment or unsafe sling angles.
Employer Responsibilities
- Supply well-maintained lifting and rigging gear that meets recognized Canadian or international standards.
- Ensure a competent person is available to oversee rigging operations.
- Provide training on sling angles, rigging techniques, and safe lifting practices.
- Follow Canadian occupational health and safety regulations and applicable industry codes of practice for load lifting and rigging.
Discussion & Questions
- What’s the safest sling angle to use when lifting a heavy load, and why?
- Has anyone experienced an issue caused by incorrect sling angles?
- What can we do to ensure sling angles are safe before starting a lift?
Encourage workers to share practical examples and raise any questions.
Commitment/Action Plan
Let’s commit to inspecting slings, calculating angles, and working with a competent person before every lift. If something doesn’t look right, stop, assess, and adjust. Taking a few minutes to confirm your sling angles could prevent a serious accident.
Wrap-Up
Sling angles matter. Using the wrong angle can overload the gear and cause the load to drop. By choosing the right method, consulting competent personnel, and inspecting gear, we can carry out safe and efficient lifts. Thank you for your attention—stay sharp and lift safely.
Standards Overview
Canadian occupational health and safety regulations require lifting and rigging equipment to be:
- Used within rated capacities.
- Maintained and inspected regularly.
- Operated under the supervision of a competent person.
- Sling angles assessed and planned appropriately before use.
Disclaimer
“The information provided in this toolbox talk is intended for informational and educational purposes only. It is not a substitute for professional legal, safety, or regulatory advice. The content reflects general best practices and industry standards but may not be applicable to all workplace environments or jurisdictions.
It is the responsibility of employers, supervisors, and workers to ensure compliance with applicable federal, provincial, and territorial laws, regulations, and standards, including but not limited to those set by the Canadian Centre for Occupational Health and Safety (CCOHS) and relevant provincial occupational health and safety authorities. Site App Pro, its affiliates, agents, or representatives—as well as the authors, presenters, and distributors of this toolbox talk—assume no liability for the use or application of the information provided.
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