🏗️ Safety in Slinging and Signalling (Rigging and Banksman) – In-Depth Theory Guide

🔓 Open Questions Explained

1. Effects of a Slewing Load

Q: State 2 effects of a slewing load that a slinger should be aware of.

✅ A:

• Outward Arc Swing: When slewing (rotating) a crane, the load doesn’t follow a perfect circle – it swings outwards due to inertia. This can pose risks to nearby workers and structures.

• Continued Swing After Stop: Once the boom stops moving, the suspended load will continue swinging forward and backward due to momentum. This “pendulum effect” can destabilize the crane or cause impact damage if uncontrolled.

🔍 Why it matters: Awareness helps slingers maintain safe distances and ensure the area is clear during boom movements.

2. WLL vs SWL

Q: What is the difference between Working Load Limit (WLL) and Safe Working Load (SWL)?

✅ A:

• WLL: Manufacturer’s maximum designed load capacity under ideal conditions.

• SWL: Adjusted load capacity based on how the sling is used (angle, hitch type, etc.).

📘 Example: A sling may have a WLL of 2 tons, but if used in a choke hitch at an angle, the SWL might reduce to 1.5 tons.

3. Miscommunication with Crane Operator

Q: What should a slinger do if they suspect the crane operator misunderstood an instruction?

✅ A:

1. STOP the operation immediately.

2. Reissue the instruction clearly.

🧠 Key point: Never assume the operator understood. Clarify before proceeding.

4. Behaviours Near Rated Capacity

Q: List 4 behaviours seen when lifting near crane capacity.

✅ A:

• Boom/Jib Deflection: Slight bending before lift-off due to high tension.

• Rearward Bounce: Crane structure “springs” back when load is lowered.

• Compression of Stabilizers: Load-side supports compress more under pressure.

• Lightening of Opposite Stabilizers: Non-load side supports may lift or feel light.

⚠️ Important: These are warning signs that you’re approaching equipment limits.

5. Estimating Load Mass

Q: Name 2 things needed to estimate load mass.

✅ A:

• Volume of the Load

• Material Density

🧮 Formula:
Mass = Volume × Density

📌 Example: A 1m³ concrete block (density ≈ 2400 kg/m³) = 2400 kg

📝 Multiple Choice Questions Deep Dive

6. Why wait before de-rigging a load?

✅ Correct: A. To allow any settling/movement of the load to occur.

📌 Insight: Movement could cause injury or instability if approached too early.

7. Crane operator does not acknowledge your instruction?

✅ Correct: A. Repeat the instruction and request acknowledgement.

💬 Communication is safety. Never proceed without confirmation.

8. Damage spotted on the load container during test lift?

✅ Correct: A. Instruct the operator to lower it carefully.

🔧 Do not attempt repairs during lifting. Lower, inspect, and reassess.

9. Unsafe or unauthorized action observed?

✅ Correct: B. Cease operation and make the load safe.

🚫 Zero tolerance for unsafe practices.

10. Uninstructed crane manoeuvre?

✅ Correct: A. Halt the operation and clarify.

👷 The slinger is in control of signalling. Operators should not act independently.

11. Purpose of risk assessment?

✅ Correct: B. Identify hazards and how to prevent them.

📊 It’s not just paperwork – it saves lives.

12. Meaning of ‘centre of gravity’?

✅ Correct: C. Point where perfect balance occurs.

🎯 Critical for balanced lifting. Load imbalance = hazard.

13. How is lifting radius calculated?

✅ Correct: D. From the centre of the slewing column.

📏 The radius directly affects crane capacity. Longer radius = less capacity.

14. Responsibility for load plans?

✅ Correct: A. True – Appointed Person is responsible.

👤 The AP ensures all lifts are planned and safe.

15. Function of a spreader beam?

✅ Correct: A. Helps maintain optimal slinging angles.

🔗 Improves balance and reduces angle stress on slings.

16. Definition of “mass”?

✅ Correct: C. The amount of matter in an object.

🧪 Mass ≠ weight. Mass is constant; weight changes with gravity.

17. Does hoist rope length affect swing?

✅ Correct: B. False – it does affect swing.

🔄 Longer rope = greater swing potential.

18. Best sling material for sharp edges?

✅ Correct: B. Chains

🔪 Webbing or fiber can get cut. Use chain slings or protect edges.

19. What does WLL stand for?

✅ Correct: A. Working Load Limit

20. SWL vs WLL again

✅ Correct: A. SWL is application-based; WLL is absolute.

📚 Tip: Always check configuration-specific SWLs.

21. Double choke hitch on a pipe?

✅ Correct: D. Apply from opposite sides to reduce rotation.

🔁 Balanced hitching minimizes spin.

22. Wind speed to stop crane operations?

✅ Correct: D. As per lifting plan.

🌬️ Lifting plans specify limits based on crane type & conditions.

23. What to do with slings after operations?

✅ Correct: A. Inspect and stow properly.

🧼 Good storage = longer lifespan = safer lifts.

24. Red threads in fiber webbing?

✅ Correct: C. Take out of use immediately.

🚩 Red = worn core. Discard to prevent sling failure.

25. International signalling standard?

✅ Correct: A. ISO 15716

📖 This is the global reference for standard hand signals in lifting.

✅ Conclusion

Proper knowledge of rigging and signalling is vital for site safety, efficient operations, and compliance with international standards. Each question in this test highlights critical decision-making points for slingers and banksmen.

💬 Have questions or want more practical examples? Drop a comment below or share your real-world lifting scenarios!