It’s NOT That Bad
Mike RiggsRigging Institute, LLC
It’s Not THAT Bad!
It’s Not THAT Bad!
It’s Not that Bad – Alloy Chain Slings
Alloy Chain Slings
An alloy chain sling shall be removed from service if conditions such as the following are present:
(c) Excessive wear… “Minimum thickness on chain links shall not be below the values listed in Table 9-1.9.4.1”
It’s Not that Bad – Alloy Chain Slings
ASME B30.9-1.9.4
Chain Sling WearChain normally wears at the interlink bearing points and at the side barrel of the link.
It’s Not that Bad – Alloy Chain Slings
INTERLINKBEARING POINT
SIDE BARREL
Normal wear areas on a chain sling are at the compressive stress area of the links.
It’s Not that Bad – Alloy Chain Slings
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Chain Sling Wear
Compressive Stress
Tensile Stress
To determine loss, measure the questionable area with calipers or no-go gauges.
It’s Not that Bad – Alloy Chain Slings
Chain Sling Wear
It takes very little wear beyond the minimum wear dimension, to cause a severe reduction of the chain’s ultimate strength.
It’s Not that Bad – Alloy Chain Slings
Chain Sling Wear
It’s Not that Bad – Wire Rope Sleeves
Wire Rope Slings
FLEMISH EYE
TURNBACK EYE
– Turnback Eye (Loopback) (not recommended)– Flemish Eye (recommended)
It’s Not that Bad – Wire Rope Sleeves
Wire Rope Sling FittingsMechanically spliced slings are fabricated in two ways:
Damaged / Suspect Flemish Eye Sleeves.
It’s Not that Bad – Wire Rope Sleeves
Cracked Sleeve
Improper Press
A flemish eye splice develops 60% or more of the sling’s minimum break strength.
Wire Rope Sling Fittings
Damaged / Suspect Turnback (loopback) Sleeves.
It’s Not that Bad – Wire Rope Sleeves
Cracked Aluminum SleeveCracked Steel Sleeve
Wire Rope Sling Fittings
Aluminum Sleeve – Failed at 5,480 lbs
It’s Not that Bad – Wire Rope Sleeves
Steel Sleeve – Failure Load Unknown
Wire Rope Sling FittingsDamaged / Suspect Turnback (loopback) Sleeves.
It’s Not that Bad – Wire Rope Sleeves
VRC: 5,000 lbs (2.5 tons) – Min. Break: 25,000 lbs1/2” Turnback Sling Testing – Worn Die
It’s Not that Bad – Wire Rope Sleeves
1/2”
20,000
21,290
VRC: 5,000 lbs (2.5 tons) – Min. Break: 25,000 lbs1/2” Turnback Sling Testing – Worn Die
It’s Not that Bad – Synthetic Web Cuts
Synthetic Web Slings
It’s Not that Bad – Synthetic Web Cuts
Synthetic Web Sling Cuts
ASME B30.9-5.9.4 removal criteria states:“A synthetic webbing sling shall be removed from service if conditions such as the following are present…(d) holes, tears, cuts, or snags…”
5 – Breaks: No Damage1/8” Cut1/4” Cut3/8” Cut1/2” Cut
It’s Not that Bad – Synthetic Web Cuts
EE1-903 Nylon Web Sling Cut Testing
No Damage: 27,510 lbs
VRC: 4,800 lbs – Min. Break: 24,000 lbs
It’s Not that Bad – Synthetic Web Cuts
Actual Breaks
EE1-903 Nylon Web Sling Cut Testing
1/8” Cut: 22,910 lbs
1/4” Cut: 17,670 lbs
It’s Not that Bad – Synthetic Web Cuts
VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling Cut Testing
Actual Breaks
3/8” Cut: 15,800 lbs
1/2” Cut: 14,000 lbs
It’s Not that Bad – Synthetic Web Cuts
VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling Cut Testing
Actual Breaks
No Damage:1/8” Cut:1/4” Cut:3/8” Cut:1/2” Cut:
Actual Breaks (lbs) % of Strength Loss
27,510 ……...….…… 0 % — +13% 22,910 …….…...…… 20% — 09%17,670 …….…..……. 36% ─ 26%15,800 ………..…….. 43% ─ 34%14,000 …………..….. 49% ─ 42%
It’s Not that Bad – Synthetic Web Cuts
Actual Minimum
VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling Cut Testing
It’s Not that Bad – Synthetic Web Cuts
VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling Cut Testing – 2
It’s Not that Bad – Synthetic Web Cuts
13,000
14,940
VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling 1/2”
UV Degradation
It’s Not that Bad – UV Degradation
The main source of UV light is the sun. welding arcs, fluorescent lighting and Xenon light (used in automobile headlights).
Ultraviolet (UV) light sources.
It’s Not that Bad – UV Degradation
It’s Not that Bad – UV Degradation
UV light has a shorter wavelength than violet light (the light we see) and is not visible to the human eye.
UV light degrades synthetic materials by transferring energy into the fibers often causing damage by breaking down the molecular bonds in the fiber structure.
Generally, darker colors provide better UV resistance than lighter colors and thicker materials resist UV light better than thinner.
Ultraviolet (UV) Stats.
It’s Not that Bad – UV Degradation
Synthetic Web Slings
Polyester web slings lost up to 30% of their strength during the first 12 months, then leveled off.
UV Degradation – Synthetic Web Slings
WSTDA UV Testing (2006)
UV Degradation – Synthetic Web Slings
WSTDA UV Testing (2006)
Nylon web slings lost up to 50%-60% of their strength 36 months, with NO indication of leveling off.
When a web sling is stiff and/or faded it is usually an indication of UV Degradation.
UV Degradation – Synthetic Web Slings
Recognizing UV Degradation
If the sling is constantly fuzzy through the webbing it is an indication of UV Degradation.
If you pop the sling and fibers float off the sling body it is an indication of UV Degradation.
Fading / Some Fuzziness
Original Color
UV Degradation – Synthetic Web Slings
Recognizing UV Degradation
Fuzziness
UV Degradation – Synthetic Web Slings
Recognizing UV Degradation
UV Degradation – Synthetic Web Slings
Break Testing of Two Identical UV Damaged Slings
Test ID: 483 - EE2-602 x 20’ Nylon Web Sling - Tested in basket configuration
Test ID: 484 - EE2-602 x 20’ Nylon Web Sling - Tested in basket configuration
Vertical Basket Capacity = 8,800 lbsMinimum Break Strength = 44,000 lbs
UV Degradation – Synthetic Web Slings
Test ID: 483 — EE2-602
Test ID: 484 — EE2-602
Actual Break: 24,790 lbs
Actual Break: 13,300 lbs
71%
UV Degradation – Synthetic Web Slings
EE2-804 with UV Degradation & Small Snag in EyeVertical Basket Capacity: 45,600 lb / Minimum Basket Brk: 228,000 lbs
Best – Black Protection
Better – Gray Protection
Poor – Treated
Worst – Untreated
UV Degradation – Synthetic Web Slings
Sling Protection
UV Degradation – Synthetic Roundslings
Synthetic Roundslings
It is difficult to determine the original color of this sling.
Synthetic Roundslings
Do roundslings lose strength when they are in this condition?
UV Degradation – Synthetic Roundslings
Original Color
UV Degradation – Synthetic Roundslings
Synthetic Roundslings
Expect up to a 30% loss of strength in severe faded conditions.
UV Degradation – Synthetic Roundslings
WSTDA RS-1 4.4.1 states:
“Polyester roundslings should be stored in a cool, dry and dark place to prevent loss of strength when not in use through exposure to ultra-violet rays.”
Synthetic Roundslings
Recognizing UV Degradation1) When roundsling covers are stiff and/or faded it
is a strong indication of UV Degradation.
2) When a cover is faded beyond recognition, remove the sling from service, you can be sure there is UV degradation to the core fiber.
UV Degradation – Synthetic Roundslings
Synthetic Roundslings
Original Testing - Results
UV Degradation – Synthetic Roundslings
Fiber Type
No UV Exposure
No Cover
DBL Yellow Poly Cover
DBL Org-Red Poly
CoverDBL Black Poly Cover
CoverMax® Cover
Base Line Percentage of Strength LOST at 500 Hours of UV Exposure to Covers/Fiber
Polyester 100%
Aramid 100%
K-Spec® 100% N/A N/A N/A
36% 12% 9% 5% 2%
28% 26% 27% 9% 2%
12% 1.13%
UV Degradation – Synthetic Roundslings
Slingmax® Testing - Results
UV Degradation – Synthetic Roundslings
Less light penetrates the covers that protect against UV the best.
Which set of polyester fibers has 500 hours of UV exposure?
No exposure
500 hrs exposure
UV Degradation – Synthetic Roundslings
Slingmax® UV Degradation Testing
DBL Wall Yellow Polyester Tubing exposure to UV
No exposure
500 hrs exposure
UV Degradation – Synthetic Roundslings
Slingmax® UV Degradation Testing
No exposure
500 hrs exposure
UV Degradation – Synthetic Roundslings
DBL Wall Black Polyester Tubing exposure to UVSlingmax® UV Degradation Testing
No exposure
500 hrs exposure
UV Degradation – Synthetic Roundslings
DBL Wall Cornermax® Tubing exposure to UVSlingmax® UV Degradation Testing
Synthetic RoundslingsTesting has taught us that:
1) Most roundsling core fibers show no visible indications of damage due to UV exposure.
2) When covers show fading it is a strong indicator that UV degradation to the core fiber has begun and may be advanced.
3) Most HP fibers, EXCEPT Aramid, show more resistance to UV degradation than polyester.
4) Aramid fibers are the most adversely affected by UV.5) Dark and/or dense covers protect the load fiber best.
UV Degradation – Synthetic Roundslings
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Thank you
? ? ? ? ? ? ? ?Mike Riggs
It’s Not THAT Bad!
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