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Understanding Sling Angles - A Comprehensive Guide

By: Dawnerz

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Time to read 6 min

Have you ever wondered why sling angles are so important in the lifting and rigging industry? Are there optimal sling angles that ensure safe and efficient operations? How do you calculate sling angles accurately?


In this article, we will dive deep into the world of sling angles and provide you with a comprehensive guide to understanding their significance. Whether you are a professional rigger or simply curious about the mechanics behind lifting heavy loads, this article will answer all your questions.

What Are Sling Angles?

A sling angle , also known as a horizontal angle, refers to the angle at which a sling meets the load being lifted. It is a critical factor in rigging operations as it directly impacts the load capacity and stability of the lift. By accurately measuring and understanding sling angles, operators can ensure safe and efficient lifting operations. The recommended angle is 30° for stability, though 60° is preferred for safety. Multi-leg slings are tagged for 60°, but can be used at 45° or 30°. However, 60° is the standard for most lifts.

Understanding and maintaining proper sling angles are crucial for the safe and effective operation of lifting equipment. By following industry guidelines and calculating the correct sling angles, operators can optimize load distribution, minimize stress on slings, and reduce the potential for accidents or equipment failure.

How to Accurately Measure Sling Angles

The tension and stress on each sling leg are influenced by the sling angle. To calculate the tension, multiply the load weight by a tension factor based on the angle. Here are the tension factors for common angles:

Sling Angle Load Chart

It is crucial to have a designated person who is competent and qualified to measure sling angles and approve lifts for safety. This individual should have a thorough understanding of sling angles and how they affect rigging performance. They should be trained to use sling angle calculators and understand the proper techniques for accurately measuring angles.

Responsibility for Measuring Sling Angles

In the lifting and rigging industry, the responsibility for measuring sling angles lies with a competent and qualified person. This individual, often referred to as the designated person , plays a critical role in ensuring that proper angles are achieved during lifting operations.


According to OSHA guidelines, a qualified person is defined as someone who possesses recognized credentials or has extensive knowledge and training in the field. It is the employer's responsibility to determine if an employee meets the qualifications based on their training, certificates, degrees, and applicable experience.


On construction sites or shop floors, the employer designates a competent person who possesses the necessary knowledge, skills, and experience to accurately measure sling angles . This designated person ensures that the lifting operations are carried out safely and efficiently, minimizing the risk of accidents and equipment failure.


By entrusting the responsibility of measuring sling angles to a competent and qualified person, businesses can prioritize rigging safety and maintain compliance with industry regulations. This proactive approach helps prevent workplace incidents, protects employees, and reduces the financial and reputational risks associated with accidents.

competent person

Lifting with Angles Smaller than 30°

When lifting with angles smaller than 30°, it is important to proceed with caution to ensure safety and prevent accidents. The critical lift plan should be implemented to mitigate the risks associated with small angles. This plan involves a comprehensive assessment of the lift, taking into account factors such as the weight of the load, the angle of the sling, and the equipment being used.


A qualified person should be responsible for approving the lift and overseeing its execution. This person should possess the necessary knowledge and experience to assess the risks and make informed decisions about the lift's feasibility and safety. Lifting with small angles requires precise calculations and careful execution.


One option to consider when working with small angles is the use of a spreader bar . A spreader bar is a lifting device that helps distribute the load more effectively and improves the lifting angle. By using a spreader bar , the stress on the slings can be minimized, reducing the risk of failure.


The ASME B30.9 Slings standard mandates the implementation of a critical lift plan for loads below 30°. Compliance with this standard ensures that proper precautions are taken to safeguard the lifting operation and protect the personnel and equipment involved.

Sling Angle

Recommended Precautions

Less than 30°

Implement a critical lift plan and involve a qualified person for approval.

30° and above

Follow standard lifting procedures and ensure proper rigging.

Importance of Knowing Sling Angles

Understanding and calculating proper sling angles is vital for ensuring the safety of lifting operations. The goal is to lift and deliver loads efficiently while minimizing risks to employees.


Optimizing Tension and Stress: By knowing the correct sling angles, the tension and stress on the slings can be optimized. This helps distribute the load evenly and reduces the risk of sling failure, protecting both workers and the lifted objects.


Minimizing Accidents: Knowing sling angles allows for the proper selection and use of rigging equipment. By using the appropriate angles, the rigging capacity can be maximized, reducing the chances of accidents and ensuring a safe working environment.


Preventing Damage: Incorrect sling angles can lead to damage to both the lifted objects and the slings themselves. By understanding and calculating optimal sling angles , the risk of damaging equipment, structures, or products can be minimized, saving time and money on repairs or replacements.


Safety should always be the top priority when conducting lifts. Proper knowledge and implementation of sling angles contribute to the overall safety and efficiency of lifting operations.

Conclusion

To ensure rigging safety , it is crucial to have a thorough understanding of sling angles. Improper sling angles can jeopardize the working load limit and significantly increase the risk of accidents and injuries. By accurately measuring sling angles, using the appropriate equipment, and adhering to safety guidelines, lifting operations can be carried out safely and efficiently.


Remember, safety should always be the top priority. Consult with qualified personnel who are competent and experienced in calculating and approving sling angles. Their expertise will help determine the correct rigging and ensure that the applied force is distributed evenly and effectively.


By prioritizing rigging safety , you can minimize the chances of lift failures, damages, and workplace incidents. Remember to refer to industry standards and guidelines, such as those set by OSHA and ASME, to ensure compliance and create a culture of safety in your lifting operations. Stay vigilant, be proactive, and make sling angles a key consideration in your rigging practices.

FAQs

What is the effect of angle on slings?

Using slings at an angle can become deadly if that angle is not taken into consideration when selecting the sling to be used. The tension on each leg of the sling is increased as the angle of lift, from horizontal, decreases. It is most desirable for a sling to have a larger angle of lift, approaching 90°.

What is the best sling angle for lifting?

Lifting and rigging specialists tend to prefer 60° angles. When a multi-leg sling is tagged, it is tagged for 60°. Slings also can be used at 45° or 30°, but for most of the lifts, 60° is the baseline sling angle that riggers want to use.

How do sling angles affect the actual stress?

This means that as the horizontal angle between the sling legs decreases, the load on each sling leg increases. The stress is the same whether a sling is used in the basket hitch or 2 slings are used, as with a 2-legged bridle hitch.

What is the maximum recommended angle between the slings?

All multi-leg chain slings exert a horizontal component of force, which increases as the angle from the vertical becomes greater. No chain sling should be used if the angle from the vertical exceeds 60˚, as beyond this point the forces in the legs drastically increase.

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