2015 CRW - Rigging Inspections: "It's Not That Bad"

transcript

It’s NOT That Bad

Mike RiggsRigging Institute, LLC

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”

ASME B30.9-1.9.4

Chain Sling WearChain normally wears at the interlink bearing points and at the side barrel of the link.

INTERLINKBEARING POINT

SIDE BARREL

Normal wear areas on a chain sling are at the compressive stress area of the links.

Chain Sling Wear

Compressive Stress

Tensile Stress

To determine loss, measure the questionable area with calipers or no-go gauges.

Chain Sling Wear

It takes very little wear beyond the minimum wear dimension, to cause a severe reduction of the chain’s ultimate strength.

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)

Wire Rope Sling FittingsMechanically spliced slings are fabricated in two ways:

Damaged / Suspect Flemish Eye 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.

Cracked Aluminum SleeveCracked Steel Sleeve

Wire Rope Sling Fittings

Aluminum Sleeve – Failed at 5,480 lbs

Steel Sleeve – Failure Load Unknown

Wire Rope Sling FittingsDamaged / Suspect Turnback (loopback) Sleeves.

VRC: 5,000 lbs (2.5 tons) – Min. Break: 25,000 lbs1/2” Turnback Sling Testing – Worn Die

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

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

EE1-903 Nylon Web Sling Cut Testing

No Damage: 27,510 lbs

VRC: 4,800 lbs – Min. Break: 24,000 lbs

Actual Breaks

EE1-903 Nylon Web Sling Cut Testing

1/8” Cut: 22,910 lbs

1/4” Cut: 17,670 lbs

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

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%

Actual Minimum

VRC: 4,800 lbs – Min. Break: 24,000 lbsEE1-903 Nylon Web Sling Cut Testing – 2

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.

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.

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)

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.

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

Fuzziness

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

Test ID: 483 — EE2-602

Test ID: 484 — EE2-602

Actual Break: 24,790 lbs

Actual Break: 13,300 lbs

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

Sling Protection

UV Degradation – Synthetic Roundslings

Synthetic Roundslings

It is difficult to determine the original color of this sling.

Do roundslings lose strength when they are in this condition?

Original Color

Expect up to a 30% loss of strength in severe faded conditions.

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.”

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.

Original Testing - Results

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%

Slingmax® Testing - Results

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

Slingmax® UV Degradation Testing

DBL Wall Yellow Polyester Tubing exposure to UV

No exposure

500 hrs exposure

Slingmax® UV Degradation Testing

No exposure

500 hrs exposure

DBL Wall Black Polyester Tubing exposure to UVSlingmax® UV Degradation Testing

No exposure

500 hrs exposure

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.

www.rigginginstitute.com

Thank you

? ? ? ? ? ? ? ?Mike Riggs

It’s Not THAT Bad!

2015 CRW - Rigging Inspections: "It's Not That Bad"

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