Mastering Lifting Slings: 14 Essential Safety Standards Guide
Introduction: When selecting sling specifications, the usage factor—affected by the dimensions, weight, shape of the load to be lifted, and the intended lifting method—must be included in calculations to determine the required ultimate working load. Additionally, working conditions and the type of load must also be taken into account.
1. Selection of Sling Specifications anD Types
When choosing sling specifications, factors such as the size, weight, shape of the load, lifting method, and their combined influence on usage must be considered in calculating the required ultimate working load. Working environment and load type must also be evaluated. The selected sling must have sufficient capacity and appropriate length for the intended use. If multiple slings are used simultaneously to lift a load, they should all be of the same type. The material of flat slings must not be affected by environmental or load conditions. Whether additional fittings or soft eyes are required, care must be taken to ensure that the end sections of the sling and auxiliary components match the lifting equipment.
2. Limitations on Sling Usage Angles
When using flat slings with soft eyes, the minimum eye length must not be less than 3.5 times the maximum thickness of the hook contact area, and the angle between the sling legs must not exceed 20°. When connecting a sling with a soft eye to lifting equipment, the contact point between the sling and the lifting device must remain straight unless the axial width of the sling does not exceed 75 mm; in such cases, the bending radius of the lifting attachment must be at least 0.75 times the axial width of the sling.
3. Following Good Lifting Practices
Plan the lifting operation carefully before beginning, including safe handling procedures.
4. Correct Use of Sling Connection Methods During Lifting
Slings must be properly positioned and connected to the load in a safe manner. Slings should be placed so that the load is evenly distributed across the width of the sling. Never tie knots or twist the sling; stitched areas must never rest directly on hooks or lifting equipment. Always place them on the straight section of the sling, and avoid damage to labels by keeping them away from the load, hooks, and tight angles.
5. Precautions for Using Multi-Part Composite Slings
The ultimate working load of multi-part composite slings depends on the symmetry of load distribution among the sling legs—specifically, whether the sling branches are symmetrically and uniformly distributed during lifting, each maintaining the same vertical angle. For three-leg composite slings, if the load is not evenly distributed and one leg bears the maximum force, the total allowable load will be based on the sum of the maximum capacities of the branch closest to the design angle. The same applies to four-leg composite slings, unless the load is rigid. Note: For rigid loads, most of the gravitational force may be carried by only three or even two legs, while the remaining leg serves merely to maintain balance.
6. Protection of Slings During Lifting
Keep slings away from sharp edges to prevent friction and wear. Whether near the load or lifting equipment, vulnerable parts of the sling must be adequately protected against damage from sharp edges and abrasion. Additional protective measures may be necessary when needed.
7. Ensuring Load Balance During Lifting
During lifting operations, slings must be used safely to prevent the load from tilting or slipping off. Slings should be arranged directly above the center of gravity of the load and the Lifting Points to ensure balance and stability. If the load’s center of gravity is not directly below the lifting point, the moving sling could shift beyond the lifting point, creating a hazardous situation.
8. Recommended Lifting Methods Using Slings
Using basket hitching ensures safer lifting since there is no locking action like in choker hitches, and the sling can pass freely through the lifting point. It is recommended to use two slings together, with the sling legs hanging as vertically as possible, which helps ensure equal load distribution among the branches.
When using flat slings for locking lifts, allow them to rest in their natural angle (120°) to avoid heat generation from friction. The sling should not be forced into a rigid position nor should it attempt to create a tight clamp. The correct and safe method is to use double-locking with one sling. Double-locking ensures safety and prevents the load from slipping out of the sling.
9. Ensure Personnel Safety
During lifting operations, closely monitor the work area to ensure personnel safety. Warn individuals in hazardous conditions and immediately evacuate them from danger zones if necessary. Hands or any other body parts must stay clear of rigging equipment to prevent injury when the sling becomes slack.
10. Use Proper Lifting Techniques
Lifting must be performed in a controlled, demonstrative manner—starting by gently picking up the load with the sling while it remains loose, then gradually tightening the sling as the load is slowly raised to its designated position. It is especially important that friction bears the load during basket lifting or free tensioning.
11. Control Load Rotation
If the load tends to tilt, lower it immediately and secure it properly to prevent unexpected rotation.
12. Avoid Impact, Dragging, Pulling, Friction, and Vibration to Prevent Damage
During lifting, ensure the load is properly secured to prevent accidental tipping or collision with other objects. Avoid dragging, pulling, or swinging the load, as these actions increase stress on the rigging. Never drag slings across the ground or rough surfaces when they are under load or bearing weight.
13. Controlled Load Lowering
When lowering the load, do so under balanced and controlled conditions.
14. Proper Storage of Rigging Equipment
After completing lifting operations, return the slings to proper storage. If no longer in use, store them in a clean, dry, well-ventilated area at room temperature, preferably on racks, away from heat sources, corrosive gases, chemicals, direct sunlight, or strong ultraviolet radiation. Prioritize the use of stored items and inspect each sling for damage before reuse; never store damaged slings.
If slings become contaminated with acids or alkalis during lifting, dilute with water or neutralize using an appropriate medium recommended for storage. Based on the material of the sling and relevant chemical properties, consult supplier recommendations—sometimes previously used products may be acceptable. If slings get wet during use or require cleaning, hang them up to air dry naturally.