Sling Angles and Lifting Capacity

PPE
English (NZ)

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

  • Overloading Slings: As the sling angle becomes flatter (closer to horizontal), the load on each sling leg increases, reducing its capacity and risking failure.

  • Improper Sling Angles: A low sling angle significantly increases tension and stress on the slings.
    ‍
  • Lack of Oversight: Lifting operations conducted without oversight from a competent person can result in unsafe practices.

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 that sling angles are within recommended safe limits.

Real-Life Case or Scenario

Where possible, use an actual incident that you have experienced or been involved in.

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. If a 60-degree angle had been used and a competent person had 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 of damaged equipment or unsafe sling angles immediately.

Employer Responsibilities

  • Supply well-maintained lifting and rigging gear that meets AS/NZS standards.

  • Ensure a competent person is available to oversee rigging operations.

  • Provide training on sling angles, rigging techniques, and safe lifting practices.
    ‍
  • Follow WorkSafe NZ’s Approved Code of Practice for Load-Lifting Rigging and relevant guidance.

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 drop the load. 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

 WorkSafe NZ requires lifting and rigging equipment to be:

  • Used within rated capacities
  • Maintained and inspected regularly
  • Operated under the supervision of a competent person
  • Sling angles must be assessed and planned appropriately before use

Disclaimer

These toolbox talks are provided for informational and educational purposes only and are not a substitute for professional legal, health and safety, or regulatory advice.

The content reflects recognised best practices and general industry standards as at the date of publication. However, it may not be applicable to all workplace environments or specific operational contexts.

It is the responsibility of the Person Conducting a Business or Undertaking (PCBU), as well as officers, workers, and other duty holders under the Health and Safety at Work Act 2015 (HSWA), to ensure compliance with all relevant laws, regulations, and WorkSafe New Zealand guidance.

The authors, presenters, and distributors of this toolbox talk disclaim all liability for any loss, damage, or injury arising from the use or reliance on the information provided. Users should seek advice from a suitably qualified health and safety professional or legal advisor for guidance tailored to their specific circumstances.

Always follow your organisation’s policies, procedures, and safe work practices to manage risks and maintain a safe and healthy workplace.

All Rights Reserved Site App Pro 2025

Last Updated:
May 12, 2025