OSHA and ASME safety standards require the user to conduct:
All wire ropes will wear out eventually and gradually lose work capability throughout their service life. That?s why periodic inspections are critical. Applicable industry standards such as ASME B30.2 for overhead and gantry cranes or federal regulations such as OSHA refer to specific inspection criteria for varied applications.
Regular inspection of wire rope and equipment should be performed for three good reasons:
All wire ropes should be thoroughly inspected at regular intervals. The longer it has been in service or the more severe the service, the more thoroughly and frequently it should be inspected. Be sure to maintain records of each inspection
Inspections should be carried out by a person who has learned through special training or practical experience what to look for and who knows how to judge the importance of any abnormal conditions they may discover. It is the inspector?s responsibility to obtain and follow the proper inspection criteria for each application inspected.
Here?s what happens when a wire breaks under tensile load exceeding its strength. It?s typically recognized by the ?cup and cone? appearance at the point of failure. The necking down of the wire at the point of failure to form the cup and cone indicates failure has occurred while the wire retained its ductility.
This is a wire with a distinct fatigue break. It?s recognized by the square end perpendicular to the wire. This break was produced by a torsion machine that?s used to measure the ductility. This break is similar to wire failures in the field caused by fatigue.
Shown here is a wire rope that has been subjected to repeated bending over sheaves under normal loads. This results in fatigue breaks in individual wires ? these breaks are square and usually in the crown of the strands.
This is an example of fatigue failure of a wire rope subjected to heavy loads over small sheaves. The breaks in the valleys of the strands are caused by ?strand nicking.? There may be crown breaks, too.
Here you see a single strand removed from a wire rope subjected to strand nicking. This condition is a result of adjacent strands rubbing against one another. While this is normal in a rope?s operation, the nicking can be accentuated by high loads, small sheaves or loss of core support. The ultimate result will be individual wire breaks in the valleys of the strands.
How Often to Inspect
Both AMSE Standard B30.9 and OSHA require that wire ropes receive two types of inspections:
Inspection shall be made at least annually and shall include a record of the inspection or of apparent conditions to provide the basis for a continuing evaluation. Inspection shall be conducted on the entire length of the sling, including splices, end attachments and ttings.
The following procedures are offered as a guide for conducting inspections:
According to ASME B30.9, you must remove a wire rope sling from service immediately if any of the following conditions are present:
|Cable-laid grommet||20 per lay|
|Less than 8-part braid||20 per braid|
|8-part braid or more||40 per braid|
Once the inspector has determined a sling is no longer usable, he should tag it immediately, ?Do Not Use.? The sling should then be destroyed as soon as possible by cutting the eye and ttings from the rope. This will prevent accidental reuse of the sling.
All of our synthetic web products are designed for long life under punishing conditions, but they will eventually wear out after extended use. The key is knowing when to replace them, and that?s why it?s very important to inspect your slings on a regular basis.
We?ve developed an inspection program based on the procedure outlined in ASME B30.9 Slings Standard that will make the most of your investment. It?s based on four sound beliefs:
The frequency of inspection depends on three important factors:
It?s a good idea for the person handling the slings to visually inspect all slings before each lift. Additional inspections should be performed at least annually by a qualified designated person and permanent records kept.
OSHA specifies, ?Each day before being used, the sling and all fastenings and attachments shall be inspected for damage or defects by a competent person designated by the employer. Additional inspections shall be performed during sling use, where service conditions warrant.? In other words, you should visually inspect your sling before each lift.
Remove all slings, including Flexi-Grip? round slings, from service if you see damage such as the following, and return to service only when approved by a designated person. These are removal criteria established by ASME B30.9 Slings Standard:
In addition, we recommend three other important reasons to remove slings from service:
While most of these standards are very specific regarding reasons for removal, others require your good judgment. The critical areas to watch are wear to the sling body, the selvage edge of webbing and the condition of the sling eyes.
Our synthetic web products don?t merely meet our own strict standards for workmanship and performance. They also meet or exceed these military and federal specifications:
In addition, all work conforms to standards established by the following national safety institutions and their respective regulations:
ASME B30.9 Slings – American Society of Mechanical Engineers
These are some of the most common types of web sling damage caused by abuse and misuse. When you see any of these problems during your regular inspection, stop. Replace the sling immediately because the damage is done. Never attempt to mend the sling yourself and, more so, never attempt to lift with these slings.
Whether a sling is damaged from improper use or normal wear, the same rule applies in all cases: Always cut the sling eyes and discard the sling right away when you see damage. Only with properly working slings can you take a load off your mind.
The distinguishing sign of a tensile break is a frayed appearance close to the point of failure or damage. This usually happens when a sling is loaded beyond its existing strength. The photo shows an example of a sling pulled to destruction on a testing machine. You can avoid tensile breaks by never overloading your sling
You can easily see a cut in your sling when you see a clean break in the webbing structure or fibers. This can results when a sling contacts a load edges, protrusions and corners, abrasive surfaces or unprotected edge of a load. This can happen anywhere on the sling body or eyes. Many slings feature Red-Guard warning yarns to alert you of serious cuts. One way you can avoid cuts from contacting sharp corners is to use wear pads on the sling to protect the fabric.
Cut and Tensile Damage
A good example is the photo shown here. It shows what can happen when you use a sling that?s already been cut by an object along one edge of the sling body. The cut sling should be removed from service, continued use will ultimately lead to sling failure. The solution, obviously, is to never use a sling after it?s been cut.
Anytime you see frayed fibers on the surface exposing the ?picks,? or cross fibers, of the webbing that hold the load-bearing (lengthwise) fibers in place, it?s abrasion damage. The most common abrasion damage occurs either when the sling slips while in contact with a load during a lift or when the sling is pulled from under a load. When you see the Red-Guard warning yarns exposed, it?s your signal that serious damage ? and loss of lifting capacity ? has occurred. We recommend that slings with any damage to load-bearing fibers be discarded. Wear pads are one way to avoid this damage.
It?s true nylon and polyester webbing are stable when exposed to many common chemicals, but they should never be exposed to any strong acids or corrosive liquids whenever possible. The same is true for metal fittings on slings
Example 1 (top photo). This is what happens when sulfuric acid, like car battery acid, is heated to the boiling point and dropped on nylon webbing. The charring on the surface fibers deteriorates the sling and will continue to get worse, severely affecting the webbing strength.
Example 2 (bottom photo). This is what happens when nylon webbing is immersed in sulfuric acid at room temperature for three weeks, resulting in major damage. Note the fibers are softened and swollen, and the entire fabric is grossly distorted, virtually destroying the webbing. You can help prevent this damage by never storing slings in areas where they may be exposed to acid or acid fumes, which are as destructive as liquid.
When inspecting a web or round sling, it shall be taken out of service immediately and returned for repair or replacement when any of the defects on the right are present.
|Missing or illegible sling identification (tag)|
|Acid or caustic burn|
|Melting or charring of any part of the sling|
|Holes, tears, cuts, abrasive wear, or snags that expose core yarns|
|Broken or worn stitching in load bearing splices|
|Excessive abrasive wear|
|Knots in any part of the sling|
|Discoloration and brittle or stiff areas on any part of the sling, which may mean chemical or ultraviolet/sunlight damage|
|Damaged rigging hardware per ASME B30.26|
|Fittings that are pitted, corroded, cracked, bent, twisted, gouged, or broken|
|Damaged hooks per ASME B30.10|
NOTE – All incoming slings for inspection and repair in the Twin-Path? department shall be identified with an “Inspection/repair” number (Ex.: TP0001) and entered in a repair log book after inspection.
6.1 Verify that a customer-owned item tag is attached which documents the customer?s name, date received, item description, and reason for return.
6.2 Inspect the sling for the following information on the tag:
6.3 Inspect the sling for any signs of damage according to the most current ASME B30.9 standard and manufacturer recommendations. This shall include any cuts, abrasions, heat damage, missing tell-tails, damaged fiber optics, missing or damaged Check-Fast? inspection System and/or abnormal deformities which shall be identified.
6.4 Should the core yarns be exposed, pull them out through the cover to check their condition. If cut, broken, or showing any damage, the sling is to be rejected and identified. If acceptable, tape over the exposed core yarns and reinsert by pulling on both ends of the sling. 6.5 Mark all cuts or abrasions on the sleeve.
6.6 If applicable, verify that the Tell-Tails extend at least 3 inches beyond the tag area of each sling (at least 5? for slings with a vertical rated capacity of 70,000 lbs. and up or those slings which are 25? long and over). Repairs shall be performed in accordance with step 6.17 of this procedure.
6.7 If applicable, verify that the fiber optic system is operational. (Repairs shall be performed in accordance with step 6.19 of this procedure).
6.8 If applicable, verify that the Check-Fast? Inspection System is not missing or damaged (Repairs shall be performed in accordance with step 6.19 of this procedure).
6.9 Verify that the tag is attached and legible and complies with the most current ASME B30.9 standard. Warnings shall be consistent with the most current verbiage found on the Slingmax? website (www.slingmax.com). (Repairs shall be performed in accordance with step 6.18 of this procedure).
6.10 Document all inspection results on the Inspection and Repair Form
6.11 All slings are required to be proof tested after repairs are performed. If repairs are not required or verification of the slings condition is needed, proof testing should be completed as outlined below.
6.12 Document the test results on a test form or computerized test cert.
6.13 Place sling in box until a determination of approval for repairs or replacement is received from the customer. Item is to be placed in the customer owned item area.
6.14 Receive the sales order package from the office. The package shall include the Inspection and Repair Form for the specific items to be repaired.
6.15 Perform the repairs identified on inspection form as follows:
6.16 Patches on the outer cover.
6.16.1 Make a patch (using the same material as the outer sleeve) with the appropriate sized Covermax? material.
Note: Single wall tubing (outer cover only) may be used if the repaired area still has the inner cover intact. Otherwise standard double-wall Covermax? shall be used.
6.16.2 Place the patch over the area to be repaired. Sew the along the entire length of the patch. The patch should be sewn inside out to hide the stitching and turned right side out over the repair area. Slingmax Technical Bulletin 44 should be referenced.
NOTE – Thread – The thread which is used to sew the sling covers and tag shall be fully compliant with the most current WSTDA-TH-1 standard (with the exception of Sparkeater Slings which is Aramid). Stitching – All stitches shall be lock-stitched and preferably continuous. When the stitching is not continuous, it shall be back-stitched or overstitched to prevent unraveling.
6.16.3 Stitch the patch ensuring to avoid penetrating the core yarns.
6.17Repairs to the Tell-Tails.
6.18 Replacement of the tag.
6.18.4 Ensure the repair agent is identified on the tag.
6.18.5 Sew the tag onto the sling by stitching on the centerline ensuring that stitches do not penetrate the core strands.
6.18.6 Remove any loose threads.
6.19 Replacement of the fiber optic system.
6.19.1 Mark the location of the cover material seam overlap.
6.19.2 Remove the tag by removing the stitches which secure the tag to the sling. Care shall be taken to avoid damage to the cover material.
6.19.3 Remove the stitches securing the sling overlap. Remove the remainder of the stitches to allow the cover to be pulled back 40? enabling access to the filler core strands.
6.19.4 Remove the tape which separates the strand paths.
6.19.5 Pull out the damaged fiber optic cable.
6.19.6 Position the tail stock at the appropriate position as determined by the sling length. Tighten the tail stock.
6.19.7 Using locking pliers or other suitable tool, clamp the end of the cover with the long (40?) rolled back cuff to the cross bar.
6.19.8 Insert the end of the replacement fiber optic cable into the path which originally had the fiber optic. Form a loop with the fiber optic cable leaving a 10? tail and tape into place.
6.19.9 Jog the fiber optic cable into the cover until the original loop is located at the drive roller.
6.19.10 Remove the tape from the fiber optic cable.
6.19.11 Using manufacturer identifying tape, bundle and tape the core strands. Starting at the 40? cuff, tape the two individual paths of the core material up to the opposite end of the sling.
6.19.12 Insert a metal probe through the previously placed fiber optic access hole. Insert the end of the fiber optic cable through the probe. Guiding the fiber optic cable, pull the probe and the fiber optic cable through the hole.
6.19.13 Roll the cover material over the exposed core. Ensure that the original marks placed instep 6.19.1 line up. Remove the sling from the fabricating machine.
6.19.14 Follow the steps shown in 6.19 for the replacement of the tag.
6.20 Replacement of the Check-Fast? Inspection System
6.21 Perform the second person inspection. Inspect for the following:
6.21.1 Document this inspection.
6.22 The non-conformance (NCR) process shall be initiated, if during the repair and inspection process, new deficiencies occur which cannot be corrected easily and quickly to bring the product into conformance.
6.23 Completed slings should be rolled or folded and individually packed in a polyethylene bag when possible. Insert appropriate literature including the warning/instruction sheets. Bagged slings should then be packed and sealed in an appropriate sized container for shipping. The outer container shall be stamped ?Opening Box with Sharp Tool May Cut and Damage Contents?.
6.24 Verify that the sales order package is documented as required and return the completed package to the office.