1. Application Engineer ACRP May 10th 2012
Mark Pederson
Application Engineer
ACRP May 10th 2012

2. Overview Lifting Sling Testing Inspection Retirement Criteria Hardware
Introduction to Effect of D:d ratio
Single leg tests
Grommet tests
Basket tests
Choker tests
Published Spec Sheet
Inspection Retirement Criteria
Sources for Guidelines
Mechanisms that Cause Damage
Inspection Items
Hardware
Class1 Rope Hardware
Class2 Rope Hardware
Synthetic Rope Specific Hardware

3. Intro to Effect of D/d on Efficiency
The Tighter the Bend the greater the stress Concentration
With High Modulus fibers this effect is more dramatic
Sling on a Pin:

4. Intro to Effect of D/d on Efficiency
Sling on a Pin:

5. Intro to Effect of D/d on Efficiency
Sling on a Pin:
Parallel Core Is effected in a bend

6. Intro to Effect of D/d on Efficiency
Sling on a Pin:
Braided Construction is beneficial

7. Single Leg Testing Single Leg Weakest at base of splice
2:1 D/d recommended
Efficiency > 1x Rope Strength

8. Single Leg Testing Single Leg
Single leg slings are used to baseline most rope strengths
Theoretical load distributions
There is a true loss in bend around pin but each leg around pin only carries ~½ T

9. Single Leg Testing Single Leg Testing Straight Pull D:d = 8 , 4 , 1
D/d = 1 did not show significant strength loss, however break occurred at the back of the eye (on the pin)

10. Grommet Testing Grommet strength is actually <2x rope strength
Current industry recommendations range from x entered

11. Grommet Testing
Grommet configuration highlights bending losses

12. Grommet Testing
D/d  Grommet Strength, Bearing size is critical for assuring proper design and maintaining grommet efficiency

13. Grommet Testing
D/d  Grommet Strength, Bearing size is critical for assuring proper design and maintaining grommet efficiency

14. Grommet Testing A 1.6-1.8x B 1.7-1.9x C 1.7x D 1.75x
Splice Placement on D:d >4 :
Splice area centered on the pin allows the legs to more evenly adjust upon loading.
Two splices do not produce a more efficient sling.
Testing has proven that the splice is more efficient with lower D:d ratios
A x
B x
C 1.7x
D 1.75x

15. Grommet Testing Grommet Weakest on the back of pin 8:1 D/d recommended
Efficiency ≤ 1.6x Rope Strength

16. Basket Testing
Basket

17. Choker Testing Current recommendations: Test Results*:
ASME B % (PET roundslings)
Flory/Richards* 60% (HMPE slings)
Test Results*:
12-strand, HMPE fiber
Ranged from 60% - 75%
(varied by manufacturer)
Choke Angle is critical
Choker strength

18. Choker Testing
Single leg and Grommet in Choker
3/8” and ¾”

19. Lifting Sling Table Layout Similar to ANSI table layout
5:1 Safety Factor built in
Common horizontal angles rated for basket lifts
Minimum D/d recommended
Reductions for lower basket D/d
Inspection and retirement Criteria included

20. Sling Table

21. Updated Sling Table
Choker Slings
Adjustable Slings

22. Large Diameter Sling Testing
Tested slings in a large range of sizes
Developed a model that is used to design project specific lifts

23. Overview Lifting Sling Testing Inspection Retirement Criteria Hardware
Single leg
Grommet
Basket
Choker
Published Spec Sheet
Inspection Retirement Criteria
Sources for Guidelines
Mechanisms that Cause Damage
Inspection Items
Hardware
Class1 Rope Hardware
Class2 Rope Hardware
Synthetic Rope Specific Hardware

24. Inspection Retirement Criteria
Sources for Guidelines
Cordage Institute - International association of rope twine and related manufactures/Suppliers .
Educating on the proper use of products through standards CI
“Fiber Rope Inspection and Retirement Criteria
Rope Type, Damage Description, Reference Txt, Reference Picture, Repair , Downgrade , Retire

25. Inspection Retirement Criteria
Sources for Guidelines
Handbook of fibre rope technology [Book] by Henry A. McKenna, J. W. S. Hearle, Nick O'Hear, Textile Institute (Manchester, England) in Books
Very similar to the Cordage Institute

26. Inspection Retirement Criteria
Sources for Guidelines
Samson Rope

27. Inspection Retirement Criteria
Mechanisms that Cause Damage
Excessive Tension / Shock Loading
Cyclic Tension Wear
External Abrasion
Cutting
Pulled Strands and Yarns
Flex Fatigue or Bending Fatigue
Terminations
Knots
Axial Compression and Kink Bands
Hockle, Twist , Kink or Corkscrew
Sunlight Degradation
Chemical and Heat Degradation
Dirt or Grit Particulate

28. Inspection Retirement Criteria
Initial Inspection IF
Rope Displays Moderate Wear
No history of use
Potential injury or damage to equipment
= Downgrade or Retire the rope
Samson / Cordage Institute / Handbook of fibre rope technology

29. Inspection Retirement Criteria
Cyclic Tension Wear
IF:
Broken Internal Filaments over Length
Matted Filaments at strand rub areas
=Downgrade / Retire
Samson / Cordage Institute / Handbook of fibre rope technology

30. Inspection Retirement Criteria
External Abrasion
IF:
Rope Cross Section reduced by 10% in whole rope
=Downgrade / Retire
Rope Cross Section reduced by 25%
=Repair/ Retire
Samson / Cordage Institute / Handbook of fibre rope technology

31. Inspection Retirement Criteria
Cutting
IF:
Rope Cross Section reduced by 10% in whole rope
=Downgrade / Retire
Rope Cross Section reduced by greater than 10%
=Repair/ Retire
Samson / Cordage Institute / Handbook of fibre rope technology

32. Inspection Retirement Criteria
Pulled Strand
Less than 15% of strands are pulled out a repair can be made.
Greater than 20% of strands are pulled out a repair should not be made. Downgrade the rope and retire
Samson / Cordage Institute / Handbook of fibre rope technology

33. Inspection Retirement Criteria
Flex Wear on Pulleys/ Rollers
IF:
Internal Fusion
Wear on strand crowns
Broken filaments at strand rub points
=Downgrade / Retire
Samson / Cordage Institute / Handbook of fibre rope technology

34. Inspection Retirement Criteria
Flex Wear on Pulleys/ Rollers

35. Inspection Retirement Criteria
Spliced Eye
IF:
Cuts
Splice Pulling out
Incorrect Splice
Damaged Thimble
=Repair

36. Inspection Retirement Criteria
Creep
IF:
Rope Exceeds limits set by manufacture
History of the rope indicates it is a concern
=Retire

37. Inspection Retirement Criteria
Compression

38. Inspection Retirement Criteria
Sunlight Degradation
IF:
Polypropolene, Brittle and broken outer fibers
= Retire
Ropes less than 1” diameter, 1yr plus exposure, aramid, nylon, polypro
=Retire/ Downgrade

39. Inspection Retirement Criteria
Chemical And Heat Degradation
IF:
Known exposure
= Retire
Discoloration, Brittle Fibers, Stiff,
=Retire

40. Inspection Retirement Criteria
Dirt or Grit
IF:
Dirt or Grit is found internally
Broken an powdery fiber present
= Retire

41. Overview Lifting Sling Testing Inspection Retirement Criteria Hardware
Single leg
Grommet
Basket
Choker
Published Spec Sheet
Inspection Retirement Criteria
Sources for Guidelines
Mechanisms that Cause Damage
Inspection Items
Hardware
Class1 Rope Hardware
Class2 Rope Hardware
Synthetic Rope Specific Hardware

42. Hardware Hardware Class1 Rope Hardware
Lower Strength , Higher Elongation Fibers
Plastic Thimbles , Non Reinforced Thimbles , Plastic Spools

43. Hardware Hardware Class2 Rope Hardware
High Strength , Low Elongation Fibers
Tubular Thimbles, Reinforced Thimbles, Aluminum Spools

44. Hardware Hardware Synthetic Rope Specific Hardware / Shackles
Wide body shackle
Crosby Sling Saver Spool

45. Hardware Shackles Standard and Wide Body Small D/d for Grommets
Quick Easy and readily available

46. Thank you!
Questions