RIGGING SAFE OPERATING PROCEDURES
All personnel involved with the use of rigging gear should be thoroughly instructed and trained to comply with the following practices:
1. Wire rope slings must not be used with loads that exceed the rated capacities outlined in enclosure (2) of the COMSECOND/COMTHIRDNCBINST 11200.11. Slings not included in the enclosure must be used only according to the manufacturer's recommendation.
2. Determine the weight of a load before attempting any lift.
3. Select a sling with sufficient capacity rating.
4. Examine all hardware, equipment, tackle, and slings before using them and destroy all defective components.
5. Use the proper hitch.
6. Guide loads with a tag line when practical.
7. When using multiple-leg slings, select the longest sling practical to reduce the stress on the individual sling legs.
8. Attach the sling securely to the load.
9. Pad or protect any sharp comers or edges the sling can come in contact with to prevent chaffing.
10. Keep slings free of kinks, loops, or twists.
11. Keep hands and fingers from between the sling and the load.
12. Start the lift slowly to avoid shock loading slings.
13. Keep slings well lubricated to prevent corrosion.
14. Do not pull slings from under a load when the load is resting on the slings; block the load up to remove slings.
Figure 6-58.-Hoisting with shears.
15. Do not shorten a sling by knotting or using wire rope clips.
16. Do not inspect wire rope slings by passing bare hands over the rope. Broken wires, if present, can cause serious injuries. When practical, leather palm gloves should be worn when working with wire rope slings.
17. Center of Balance. It is very important that in the rigging process that the load is stable. A stable load is a load in which the center of balance of the load is directly below the hook, as shown in figure 6-59. When a load is suspended, it will always shift to that position below the hook. To rig a stable load, establish the center of balance (C/B). Once you have done this, simply swing the hook over the C/B and select the length of slings needed from the hook to the lifting point of the load.
18. When using a multi-legged bridle sling, do not forget it is wrong to assume that a three- or four-leg hitch will safely lift a load equal to the safe load on one leg multiplied by the number of legs. With a four-legged bridle sling lifting a rigid load, it is possible for two of the legs to support practically the full load while the other two only balance it (fig. 6-60).
Figure 6-59.-Example of a load shifting when lifted.
Figure 6-60.-Multi-legged bridle sling lifting a load.
NOTE: If all the legs of a multi-legged sling are not required, secure the remaining legs out of the way, as shown in figure 6-61.
Figure 6-61.-Secure sling legs that are not used.