Warnings

Sling Warnings

Slings can fail if damaged, misused, or overloaded. Inspect before use. Damaged slings shall not be used. Use only if trained. Do not exceed rated capacity. Protect sling from being cut by load edges, corners, protrusions, and abrasive surfaces. Avoid exposure to acid, alkali, and temperatures over 180 degrees Fahrenheit. Death or injury can occur from improper use or maintenance.

Inspection of Wire Rope

INTRODUCTION

The most important aspect of operating a rope safely is regular proper inspection. ASME crane safety standards such as B30.2 and B30.5 provide detailed inspection procedures and retirement criteria. Both standards specify that all running ropes in service should be visually inspected once each working day and shall consist of observation of all rope that can reasonably be expected to be in use during operations on that day. The inspection must be more than just a quick look. It needs to be done carefully and in enough light to find damage or broken wires that may require the rope to be taken out of service. It must also be remembered that a dirty or greasy rope is almost impossible to inspect properly, as dirt and grease may hide problem areas. The individual making the inspection should be familiar with the machine, the wire rope, and that application. The B30 standards provide information on both a frequent inspection to be done daily and a much more detailed periodic inspection that is done on a weekly or monthly basis.

FREQUENT INSPECTION

As stated previously, all running ropes in service should be visually inspected once each working day and shall consist of observation of all rope that can reasonably be expected to be in use during operations on that day. The inspector should know where and how rope on the particular application wears out so that the daily inspection can be focused on the known wear areas. Special care should always be taken when inspecting common repetitive wear sections such as:

Flange step up, cross over points and repetitive pick up on the drum; areas of the rope operating through a reverse bend in the reeving system, equalizer sheaves, and end connections. The inspector should be concerned with discovering gross damage that may be an immediate hazard. Specific types of damage include the following:

Distortion to the uniform structure of the rope; broken wires; corrosion, gross damage to or deterioration of end connections, evidence of heat/electrical/lightning damage, and localized change in lubrication condition.

When damage is discovered, a qualified person must evaluate affected sections as detailed in the rope replacement section below to determine if the rope needs to be removed from service. The B30 standards do not require frequent inspections to be documented, but it is a good idea to keep a frequent inspection log on the crane, simply noting time, date and identity of the inspector.

PERIODIC INSPECTION

The inspection frequency needs to be based on factors such as expected rope life as determined by experience on the particular installation or similar installations, severity of environment, percentage of capacity lifts, frequency rates of operation, and exposure to shock loads. Inspections need not be at equal calendar intervals and should be more frequent as the rope approaches the end of its useful life. There are many duty cycle rope applications where the service life is less than a month, or sometimes even a week in severe service conditions, so a periodic level of inspection may have to be performed daily.

The periodic inspection must cover the surface of the entire rope length and no attempt should be made to open the rope. In addition to common repetitive wear sections checked during the frequent inspection, additional sections prone to rapid deterioration such as the following need special attention.

  • Locations where rope vibrations are damped, such as the following: sections in contact with equalizer sheaves, or other sheaves where rope travel is limited; sections of the rope at or near end connections where corroded or broken wires may protrude; bridle reeving in the boom hoist ropes; repetitive pickup points and  crossover and change of layer points at flanges on drums; fleeting or deflector sheaves.

In addition to specific types of damage listed in the frequent inspection section, these additional items need to be addressed: Measuring the rope diameter in numerous locations to assess uniform loss of diameter along the entire length of rope; close visual observation of the entire length to identify; lengthening of lay in localized areas; diameter reduction in localized areas; distortion of rope structure (kinking, birdcaging, crushing); steel core protrusion between the outer strands; internal corrosion; wear of outside wires; more detailed inspection of end connections for broken wires and corrosion; severely corroded, cracked, bent, worn or improperly applied end connections; waviness (corkscrew effect) of rope; high or low strand.

To establish data as a basis for judging the proper time for replacement, a dated report of rope condition at each periodic inspection must be kept on file. This report shall cover points of deterioration listed above. If the rope is replaced, only the fact that the rope was replaced need be recorded.

Certain types of ropes and applications require special attention and require reduced time intervals between periodic inspections:

  • Rotation Resistant ropes have a unique construction and are susceptible to damage and increased deterioration when working under difficult conditions such as duty cycle operation.
  • Boom hoist ropes because of the importance of their function and because their location may make inspection difficult

ROPE REPLACEMENT

There are no precise rules to determine the exact time for the replacement of the rope since many variable factors are involved. Once a rope reaches any one of the removal criteria, it must be replaced immediately unless allowed to operate to the end of the work shift by the judgment of a qualified person. If the report was not removed immediately, it shall be replaced before the end of the next work shift. Specific inspection attributes and removal criteria are:

(1) Broken wires: (a) For ropes operating on equipment covered by B30.5: In running ropes, 6 randomly distributed wire breaks per rope lay or 3 wire breaks per strand per rope lay. A rope lay is the distance that it takes one outer strand to make one complete revolution around the rope. A 6-strand rope will typically have a rope lay of 6.4 times the rope diameter (i.e. a 1/2” 6x25FW EIP IWRC RRL rope will have rope lay of 3.2”) (b) For ropes operating on equipment covered by B30.2, in running ropes is 12 randomly distributed wire breaks per rope lay or four wire breaks per strand (c) For all categories of Rotation Resistant ropes, the retirement criteria is 2 wire breaks in 6 rope diameters or 4 wire breaks on 30 rope diameters (i.e. 6 rope diameters in a 1” rope is 6”) (d) One broken outer wire at the contact point with the core which has worked its way out of the rope structure and protrudes, loops out or is slightly raised from the body of the rope

Note: Broken wire removal criteria cited in this volume apply to wire rope operating on steel sheaves and drums and wire rope operating on multilayer drums regardless of sheave material. Due to the difficulty in detecting wire breaks when polymer are utilized with single layer drums, the user should contact the sheave manufacturer for broken wire removal criteria.

Reductions from nominal diameter greater than 5% (Minimum Value = Nominal Diameter x .95)

Distortion of rope structure: (a) Damage resulting in distortion of the rope structure (e.g., kinking, birdcaging, crushing) (b) Steel core protrusion between the outer strands (c) Localized change in lay length (d) Changes in original geometry due to crushing forces where the diameter across the distorted section is 5/6 of the nominal diameter.

(4) Waviness (corkscrew effect) in the rope that causes overall diameter to increase to a value greater than 110% of nominal rope diameter.

(5) A high or low strand that is higher or lower than that of the strand diameter above or below the surface of the rope.

(6) Any apparent damage from a heat source including, but not limited to welding, power line strikes, or lightning.

(7) Widespread or localized external corrosion as evidenced by pitting, and obvious signs of internal corrosion such as magnetic debris coming from valleys.

(8) Severely corroded, cracked, bent, worn, grossly damaged, or improperly installed end connections

Note: Consult the latest edition of the ASME B30 Volume that applies to your crane as removal criteria may be updated over time based on the latest knowledge and information. All rope that has been idle for a month or more due to shut down or storage of a crane should be given a detailed inspection according to the requirements of the periodic inspection provided by the B30 standards.

ROPE SERVICE LIFE

A long-range inspection program should be established and should include records on the examination of ropes removed from service so that a relationship can be established between visual observation and actual condition of the internal structure. There are a wide variety of wire rope constructions available to be used on cranes. It is important that the correct rope be used for each application. Because wire rope wears in service, the method by which the rope wears is an important factor in determining the most suitable rope. Replacement rope must have a rated strength at least equal to the original rope supplied or recommended for the machine. Any change from the original specification for the rope must be specific by the wire rope manufacturer, crane manufacturer, or a qualified person. When there is a question, consult with Bridon American about the rope construction most appropriate for the application.

Synthetic Web Sling Safety Bulletin

Warning: This bulletin contains important safety information about the use of synthetic web slings. However, it does not contain all the information you need to know about handling, lifting and manipulating materials and loads safely. Sling use is only one part of a lifting system and it is your responsibility to consider all risk factors prior to using any rigging device or product. Failure to do this may result in severe injury or death due to sling failure and/or loss of load.

The following six points briefly summarize some important safety issues:

  1. All users must be trained in sling selection, use and inspection, cautions to personnel, environmental effects and rigging practices.
  2. Inspect sling for damage regularly, if the sling is damaged, remove it from service.
  3. Protect sling from damage. ALWAYS protect slings in contact with edges, corners, protrusions, or abrasive surfaces with materials of sufficientstrength, thickness and construction to prevent damage.
  4. Do not exceed a sling’s rated capacity. Always consider the effect of sling angle and tension on the sling’s rated capacity.
  5. Do not stand on, under or near a load with the sling under tension. All personnel should be alert to dangers of falling and/or uncontrolled loads, sling tension and the potential for snagging.
  6. Maintain and store slings properly. Slings should be protected from mechanical, chemical and environmental damage.
  1. All Sling Users Must be Trained and Knowledgeable

All web sling users must be trained on the proper use of web slings. The American Society of Mechanical Engineers, Safety Standard for Slings (ASME B30.9) states:

“Synthetic webbing sling users shall be trained in the selection, inspection, cautions to personnel, e­ffects of the environment and rigging practices as covered” by Chapter 9-5.

OSHA Guidance on Safe Sling Use (29 CFR 1910.184) states that a “qualified person” is one:

“who, by possession of a recognized degree or certificate of professional standing in an applicable field, or who, by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject matter and work.”

It is important that all sling users be knowledgeable about the safe and proper use and application of slings and be thoroughly familiar with the manufacturer’s recommendations and safety materials provided with each product. In addition, all sling users need to be aware of their responsibilities as outlined in all applicable standards and regulations.

If you are unsure whether you are properly trained and knowledgeable, or if you are unsure of what the standards and regulations require of you, ask your employer for information and/or training— DO NOT use web slings until you are absolutely sure of what you are doing. Remember, when it comes to using web slings, lack of skill, knowledge and care can result in severe INJURY or DEATH to you and others.

2.Slings Must Be Regularly and Properly Inspected

Even seemingly “minor” damage to a web sling can significantly reduce its capacity to hold or lift objects and increases the chance that the sling will fail during use. For example, one sling manufacturer has shown that a 3/8″ (9.5mm) cut (much smaller than the cut shown in Table 2) caused a sling to break under load at almost hal­ts non-damaged capacity. Therefore, it is very important that web slings are regularly and properly inspected. If you are not sure whether a sling is damaged, DO NOT USE IT

2a. How to inspect slings

To detect possible damage, you should perform a visual inspection of the entire sling and also feel along its entire length, as some damage may be felt more than seen. You should look and feel for any of the types of conditions listed in Table 1. Table 2 shows examples of some of these types of damage, but note that they are relatively extreme examples provided for illustration purposes only.

2b. What to do if you identify damage in a sling

If you identify ANY of these types of damage in a sling, remove it from service immediately even if the damage you feel or see is not as extensive as shown in the pictures in Table 2. Slings that are removed from service must be destroyed and rendered completely unusable unless they can be repaired and proof tested by the sling’s manufacturer or other quali­fied person. You should never ignore sling damage or attempt to perform temporary ­field repairs of damaged slings (e.g., tie knots in the webbing, etc.).

The entire web sling must be inspected regularly and it shall be removed from service if ANY of the following are detected:

  • If sling identification tag is missing or not readable.
  • Holes, tears, cuts, snags or embedded materials.
  • Broken or worn stitches in the load bearing splices.
  • Knots in any part of the sling webbing.
  • Acid or alkali burns.
  • Melting, charring or weld spatter on any part of the web sling
  • Excessive abrasive wear or crushed webbing.
  • Signs of Ultraviolet (UV) light degradation.
  • Distortion, excessive pitting, corrosion or other damage to­tting(s).
  • If provided, exposed red core yarn. However if damage is present and red yarns are not exposed DO NOT USE the sling.
  • Any conditions which cause doubt as to the strength of the web sling.

2c. How often to inspect slings

A three-stage procedure is recommended to help ensure that web slings are inspected with appropriate frequency:

Initial Inspection—Whenever a sling is initially received, it must be inspected by a designated person to help ensure that the correct web sling has been received and is undamaged and that the web sling meets applicable requirements for its intended use.

Frequent Inspection—The entire sling must be inspected before each shift or day in Normal service and before each use in Severe service applications.

Periodic Inspection—Every sling must be inspected “periodically” by a qualified and designated person. In order to validate the frequent level of inspection, the periodic inspection should be performed by someone other than the individual(s) who most commonly performs the frequent inspection. The frequency of periodic inspections is based on the sling’s actual or expected frequency of use, severity of service conditions, the nature of the work performed with the sling and experience gained during the inspection of other slings used in similar circumstances. General guidelines for the frequency of periodic inspections are:

  • Normal service—yearly
  • Severe service—monthly to quarterly
  • Special service—as recommended by a qualified person Periodic inspections intervals must not exceed one year.

Written records are not required for frequent inspections, but WSTDA WS-1 or ASME B30.9 require that a written record of the most recent periodic inspection be maintained. See WSTDA WS-1 or ASME B30.9 for more information about definitions of Normal, Severe and Special service conditions.

3. Slings Must be Adequately Protected from Damage

3a. Avoid environmental degradation

Environmental factors such as an exposure to sunlight, dirt or gritty-type matter and cyclical changes in temperature and humidity, can result in an accelerated deterioration of web slings. The rate of this deterioration will vary with the level of exposure to these conditions and with the thickness of the sling material. For example, single ply slings will generally degrade more rapidly with this exposure than multiple ply slings. Web slings that are used outdoors regularly should generally be permanently removed from service within a period of 2 to 4 years. All web slings that are exposed to these conditions should be highly scrutinized during their inspections.

  • Visible indications of such deterioration can include the following:
  • Fading of webbing color.
  • Uneven or disoriented surface yarn of the webbing.
  • Shortening of the sling length.
  • Reduction in elasticity and strength of the sling material due to an exposure to sunlight, often evident by an accelerated abrasive damage to the surface yarn of the sling.
  • Breakage or damage to yarn fibers, often evident by a fuzzy appearance of the web.
  • Stiffening of the web, which can become particularly evident when web slings are exposed to outdoor conditions without being used or cyclically tensioned.

3b. Avoid actions that cause damage to slings

  • You should always avoid any action that causes the types of damage identified in the previous section of this Safety Bulletin, including (but not limited to):
  • Dropping or dragging slings on the ground, floor or over abrasive surfaces.
  • Pulling slings from under loads when the load is resting on the sling—place blocks under load if feasible.
  • Shortening or adjusting sling using methods not approved by the sling manufacturer or qualified person.
  • Twisting, kinking or knotting the sling.
  • Exposing slings to damaging acids or alkalis.
  • Exposing slings to sources of heat damage or weld spatter.
  • Using slings or allowing exposure to temperatures above 194°F (90°C) or below -40°F (-40°C).
  • “Tip loading” a sling on a hook instead of centering it in the base or “bowl” of the hook.
  • Using hooks, shackles or other hardware that have edges or surfaces that could damage sling.
  • Running/driving over slings with a vehicle or other equipment. Synthetic slings are affected by some chemicals ranging from little to total degradation. Time, temperature and concentration factors affect the degradation. For specific applications, consult the manufacturer. In addition, water absorption can decrease the strength of nylon web slings by as much as 10–15% (its strength returns when the sling dries completely). For specific applications, consult the manufacturer.

3c. Safeguard slings with sufficient protection

Synthetic web slings can be damaged, abraded or cut as tension and compression between the sling, the connection points and the load develops. Surfaces in contact with the sling do not have to be very abrasive or have “razor” sharp edges in order to create the conditions for sling failure. Therefore, web slings must ALWAYS be protected from being cut or damaged by corners, edges, protrusions or abrasive surfaces with protection sufficient for the intended purpose.

There are a variety of types of ways to protect slings from such damage. A qualified person might select and use appropriate engineered protectors/softeners—commercially available products (e.g., sleeves, wear pads, edge wraps, body wraps, corner protectors, etc.) specifically designed to protect slings from damage. A qualified person might also design and construct their own methods of protection so long as the sling is adequately protected from and/or kept off of the damaging edge surface.

Regardless of the particular method chosen, the goal is to ensure that the sling, under tension, maintains its ability to securely lift the load while avoiding contact with damaging or abrasive surfaces under tension. A qualified person must carefully consider the most appropriate means to accomplish this goal. The protection used should not be makeshift (i.e., selecting and using cardboard, work gloves or other such items based solely on convenience or availability).

Regardless of the approach taken, a qualified person must ensure that the protection method chosen is appropriate for the types of damage to which the slings will be exposed. For instance, some protection provides abrasion resistance, but offers virtually no protection against cuts. Several “test” lifts, done in a non-consequence setting, may be necessary to determine the suitability of the protection device(s). After each “test” lift, the protection device(s) and sling(s) need to be inspected for damage and suitability. You should keep in mind that no protection is “cut proof” and you should always operate within the specified limits of the sling and its accessories (e.g., fixtures, hardware, protection, etc.).

4. Always Use Slings Properly

When lifting loads, a trained, qualified and knowledgeable user must take into account the factors and issues addressed in this bulletin, as well as considering any other relevant factors not addressed herein (see Table 4). Among the factors related specifically to web slings, users must perform several activities, including (but not limited to) those discussed in the following subsections.

4a. Assess the load

Determine the weight of the load and make sure it does not exceed the sling’s rated capacity or the capacity of any of the components of the rigging system. Users must also determine the load’s center of gravity (CG) to make sure the rigging system used will be able to retain and control the load once lifted.

4b. Select an appropriate sling/configuration

Select a sling having suitable characteristics for the type, size and weight of the load, the type of hitch (see Table 3) and the environment. The sling must be securely attached to the load and rigged in a manner to provide for load control to prevent slipping, sliding and/or loss of the load. A trained, qualified and knowledgeable user must determine the most appropriate method of rigging to help ensure a safe lift and control of the load.

Synthetic Web Sling Load Angle

Another important consideration is the sling-to-load angle—the angle formed between a horizontal line and the sling leg or body. This angle is very important and can have a dramatic effect on the rated capacity of the sling. When the sling-to-load angle decreases, the load on each leg increases. This principle applies in a number of conditions, including when one sling is used to lift at an angle and when a basket hitch or multi-legged bridle sling is used. Table 5 provides information about increased tension as a function of sling-to-load angle (assuming equally-loaded sling legs). Sling angles of less than 30 degrees are not recommended.

Similarly, when the angle of choke is less than 120 degrees, the sling choker hitch capacity decreases. To determine the actual sling capacity at a given angle of choke, multiply the sling capacity rating (for a choker hitch) by the appropriate reduction factor determined from Table 6.

4c. Do not misuse the sling

Avoid accelerating or decelerating the load too quickly (i.e.,“shockEWI loading”).  Do not use slings to pull on stuck or snagged objects MISSING and do not use slings for towing purposes. A web sling should only be used for lifting loads.

5. Make Sure All Personnel are Clear of Loads and Alert to Risks

Even if you account for all of the factors/issues discussed in this Safety Bulletin, things can still go wrong. Therefore, all personnel must stand clear of lifted loads and never be under, on or near suspended loads.

When using slings, no part of the body should be placed between the sling and load or between the sling and lifting hook. In addition, personnel must be alert to the potential for the sling to become snagged during a lift. Never use a web sling to pull on objects in a snagged or constrained condition.

6. Properly Store and Maintain Slings

In order to prevent damage to slings when not in use, you should store slings in a cool, dry and dark location. Slings should be stored in an area free from environmental or mechanical sources of damage, such as: weld spatter, splinters from grinding or machining, heat sources, chemical exposure, etc. Also, keep slings clean and free of dirt, grime and foreign materials.

If slings are cleaned, use only mild soap and water. Rinse sling thoroughly and let it dry completely before placing the sling back into storage or use. Do not machine wash slings. Machine washing results in significant loss of sling strength.

Where to Find Additional Information

This bulletin does not provide you with all the information you need to know in order to be considered trained and knowledgeable about rigging and lifting loads, but it does provide important information about the use of web slings within a rigging system. If you need more information about web slings and rigging practices or your responsibilities according to regulations and standards, talk to your employer. You and your employer can consult a number of sources o­n formation to help ensure that you are properly trained and knowledgeable when using web slings, including (but not limited to):

  • WSTDA-WS-1—Recommended Standard Specifications for Synthetic Web Slings
  • ASME B30.9—Synthetic Webbing Slings: Selection, Use and Maintenance
  • OSHA 29 CFR 1910.184—Slings.
  • Rigging handbooks.
  • OSHA Guidance on Safe Sling Use (https://www.osha.gov/dsg/guidance/slings/synth-web.html)
  • Manufacturer’s catalog, manual, website, bulletins, etc
  • Formal training provided by manufacturers or other outside entities

Synthetic Round Sling Safety Bulletin

Warning: This bulletin contains important safety information about the use of synthetic roundslings. However, it DOES NOT contain all the information you need to know about handling, lifting and manipulating materials and loads safely. Sling use is only one part of a lifting system and it is your responsibility to consider all risk factors prior to using any rigging device or product.

Warning: This bulletin contains important safety information about the use of synthetic roundslings. However, it does not contain all the information you need to know about handling, lifting and manipulating materials and loads safely. Sling use is only one part of a lifting system and it is your responsibility to consider all risk factors prior to using any rigging device or product. Failure to do this may result in severe injury or death due to sling failure and/or loss of load.

The following six points briefly summarize some important safety issues:

  1. All users must be trained in sling selection, use and inspection, cautions to personnel, environmental effects and rigging practices.
  2. Inspect sling for damage regularly, if the sling is damaged, remove it from service.
  3. Protect sling from damage. ALWAYS protect slings in contact with edges, corners, protrusions, or abrasive surfaces with materials of sufficient strength, thickness and construction to prevent damage.
  4. Do not exceed a sling’s rated capacity. Always consider the effect of sling angle and tension on the sling’s rated capacity.
  5. Do not stand on, under or near a load with the sling under tension. All personnel should be alert to dangers of falling and/or uncontrolled loads, sling tension and the potential for snagging.
  6. Maintain and store slings properly. Slings should be protected from mechanical, chemical and environmental damage.
  1. All Sling Users Must be Trained and Knowledgeable

All roundsling users must be trained on the proper use of web slings. The American Society of Mechanical Engineers, Safety Standard for Slings (ASME B30.9) states:

“Synthetic webbing sling users shall be trained in the selection, inspection, cautions to personnel, e­ffects of the environment and rigging practices as covered” by Chapter 9-5.

OSHA Guidance on Safe Sling Use (29 CFR 1910.184) states that a “qualified person” is one:

“who, by possession of a recognized degree or certificate of professional standing in an applicable field, or who, by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject matter and work.”

It is important that all sling users be knowledgeable about the safe and proper use and application of slings and be thoroughly familiar with the manufacturer’s recommendations and safety materials provided with each product. In addition, all sling users need to be aware of their responsibilities as outlined in all applicable standards and regulations.

If you are unsure whether you are properly trained and knowledgeable, or if you are unsure of what the standards and regulations require of you, ask your employer for information and/or training— DO NOT use web slings until you are absolutely sure of what you are doing. Remember, when it comes to using web slings, lack of skill, knowledge and care can result in severe INJURY or DEATH to you and others.

2.Slings Must Be Regularly and Properly Inspected

Even seemingly “minor” damage to a web sling can significantly reduce its capacity to hold or lift objects and increases the chance that the sling will fail during use. For example, one sling manufacturer has shown that a 3/8″ (9.5mm) cut (much smaller than the cut shown in Table 2) caused a sling to break under load at almost hal­ts non-damaged capacity. Therefore, it is very important that web slings are regularly and properly inspected. If you are not sure whether a sling is damaged, DO NOT USE IT

2a. How to inspect slings

To detect possible damage, you should perform a visual inspection of the entire sling and also feel along its entire length, as some damage may be felt more than seen. You should look and feel for any of the types of conditions listed in Table 1. Table 2 shows examples of some of these types of damage, but note that they are relatively extreme examples provided for illustration purposes only.

2b. What to do if you identify damage in a sling

If you identify ANY of these types of damage in a sling, remove it from service immediately even if the damage you feel or see is not as extensive as shown in the pictures in Table 2. Slings that are removed from service must be destroyed and rendered completely unusable unless they can be repaired and proof tested by the sling’s manufacturer or other quali­fied person. You should never ignore sling damage or attempt to perform temporary ­field repairs of damaged slings (e.g., tie knots in the webbing, etc.).

The entire roundsling must be inspected regularly and it shall be removed from service if ANY of the following are detected:

  • If roundsling identification tag is missing or not readable.
  • Holes, tears, cuts, embedded materials, excessive abrasive, wear, or snags that expose the core yarn of the roundsling.
  • Broken or worn stitches in the load bearing splices.
  • If roundsling has been tied in to one or more knots.
  • Acid or caustic burns of the roundsling.
  • Melting, charring or weld spatter of any part of the roundsling.
  • Distortion, excessive pitting, corrosion or other damage to fitting(s).
  • Broken or worn stitching in the cover which exposes the core yarn.
  • Any conditions which cause doubt as to the strength of the roundsling.

2c. How often to inspect slings

A three-stage procedure is recommended to help ensure that web slings are inspected with appropriate frequency:

Initial Inspection—Whenever a sling is initially received, it must be inspected by a designated person to help ensure that the correct web sling has been received and is undamaged and that the web sling meets applicable requirements for its intended use.

Frequent Inspection—The entire sling must be inspected before each shift or day in Normal service and before each use in Severe service applications.

Periodic Inspection—Every sling must be inspected “periodically” by a qualified and designated person. In order to validate the frequent level of inspection, the periodic inspection should be performed by someone other than the individual(s) who most commonly performs the frequent inspection. The frequency of periodic inspections is based on the sling’s actual or expected frequency of use, severity of service conditions, the nature of the work performed with the sling and experience gained during the inspection of other slings used in similar circumstances. General guidelines for the frequency of periodic inspections are:

  • Normal service—yearly
  • Severe service—monthly to quarterly
  • Special service—as recommended by a qualified person Periodic inspections intervals must not exceed one year.

Written records are not required for frequent inspections, but WSTDA WS-1 or ASME B30.9 require that a written record of the most recent periodic inspection be maintained. See WSTDA WS-1 or ASME B30.9 for more information about definitions of Normal, Severe and Special service conditions.

3. Slings Must be Adequately Protected from Damage

3a. Avoid actions that cause damage to slings

You should always avoid any action that causes the types of damage identified in the previous section of the Safety Bulletin, including (but not limited to):

  • Dropping or dragging slings on the ground, floor or over abrasive surfaces.
  • Pulling slings from under loads when the load is resting on the sling—place blocks under the load if feasible.
  • Shortening or adjusting sling using methods not approved by the sling manufacturer or qualified person.
  • Twisting, kinking, or knotting the sling.
  • Exposing slings to damaging acids or alkalis.
  • Exposing slings to sources of heat damage or weld spatter.
  • Using slings or allowing exposure to temperatures above 194°F (90°C) or below -40°F (-40°C).
  • “Tip loading” a sling on a hook instead of centering it in the base or “bowl” of the hook.
  • Using hooks, shackles or other hardware that have edges or surfaces that could damage sling.
  • Running/driving over slings with a vehicle or other equipment.

Synthetic slings are affected by some chemicals ranging from little to total degradation. Time, temperature and concentration factors affect the degradation. For specific applications, consult the manufacturer.

3b. Safeguard slings with sufficient protection

Synthetic slings can be damaged, abraded or cut as tension and compression between the sling, the connection points and the cargo develops. Surfaces in contact with the sling do not have to be very abrasive or have “razor” sharp edges in order to create the conditions for sling failure. Therefore, roundslings must ALWAYS be protected from being cut or damaged by corners, protrusions, or from contact with edges that are not smooth or well rounded with materials sufficient for the intended purpose. Roundslings should be protected from abrasive surfaces.

There are a variety of types of ways to protect slings from such damage. A qualified person might select and use appropriately engineered protectors/softeners—commercially available products (e.g., sleeves, wear pads, corner protectors, etc.) specifically designed to protect slings from damage. A qualified person might also design and construct their own methods of protection so long as the sling is adequately protected from and/or kept off of the damaging edge surface.

Regardless of the particular method chosen, the goal is to ensure that the sling, under tension, maintains its ability to securely lift the load while avoiding contact with damaging or abrasive surfaces under tension. A qualified person must carefully consider the most appropriate means to accomplish this goal. The protection used should not be makeshift (i.e. , selecting and using cardboard, work gloves or other such items based solely on convenience or availability).

Regardless of the approach taken, a qualified person must ensure that the protection method chosen is appropriate for the types of damage to which the slings will be exposed. For instance, some protection provides abrasion resistance, but offers virtually no protection against cuts. Several “test” lifts, done in a non-consequence setting, may be necessary to determine the suitability of the protection device(s). After each “test” lift, the protection device(s) and sling(s) need to be inspected for damage and suitability. You should keep in mind that no protection is “cut proof” and you should always operate within the specified limits of the sling and its accessories (e.g., fixtures, hardware, protection, etc.).

Roundslings must always be protected from coming into direct contact with any edges unless the contacting edges meet both of the following criteria:

  • The edges must be smooth and well-rounded. Edges that are chamfered or flattened at an angle do not meet this criteria.
  • The size of the edge radii must be adequately large. Table 3 shows the minimum edge radii suitable for contact with

One way to measure an edge radius is to measure the distance between the leading edge of the radius that is being measured (Point A) and the point where the radius initiates from the bottom edge of the surface (Point B) (see Figure 1).

In order to protect the roundsling, it is also necessary to select and use proper connection hardware. Connection hardware should be selected so that either:

  • it conforms to the size requirements listed in Table 4 (choker and vertical hitches) or Table 5 (basket hitch)
  • the bearing stress value at the connection does not exceed 7,000 lbs./in² during sling loading (see WSTDA RS-1, Section 4.7 for the procedure for calculating bearing stress)

4. Always Use Slings Properly

When lifting loads, a trained, qualified and knowledgeable user must take into account the factors and issues addressed in this bulletin, as
well as considering any other relevant factors not addressed herein (see Table 6). Among the factors related specifically to roundslings,
users must perform several activities, including (but not limited to) those discussed in the following subsections.

4a. Assess the load

Determine the weight of the load and make sure it does not exceed the sling’s rated capacity or the capacity of any of the components of the rigging system. Users must also determine the load’s center of gravity (CG) to make sure the rigging system used will be able to retain and control the load once lifted.

4b. Select an appropriate sling/configuration

Select a sling having suitable characteristics for the type, size and weight of the load, the type of hitch (see Table 7) and the environment. The sling must be securely attached to the load and rigged in a manner to provide for load control to prevent slipping, sliding and/or loss of the load. A trained, qualified and knowledgeable user must determine the most appropriate method of rigging to help ensure a safe lift and control of the load.

Another important consideration is the sling-to-load angle—the angle between a horizontal line and the sling leg or body. This angle is very important and can have a dramatic effect on the rated capacity of leg increases. This principle applies in a number of conditions, including when one sling is used to lift at an angle and when a basket hitch or multi-legged bridle sling is used. Table 8 provides information about increased tension as a function of sling-to-load angle (assuming hitch or multi-legged bridle sling is used. Table 8 provides information  43 equally loaded sling legs. Sling angles of less than 30 degrees are not recommended.

Similarly, when the angle of choke is less than 120 degrees, the sling choker hitch capacity decreases. To determine the actual sling capacity at a given angle of choke, multiply the sling capacity rating (for a choker hitch) by the appropriate reduction factor determined from Table 9.

4c. Do not misuse the sling

Avoid accelerating or decelerating the load too quickly (i.e. “shock loading”). Do not use slings to pull on stuck or snagged objects and do not use slings for towing purposes. A roundsling should only be used for lifting loads.

5. Make Sure All Personnel are Clear of Loads and Alert to Risks

Even if you account for all of the factors/issues discussed in this Safety Bulletin, things can still go wrong. Therefore, all personnel must stand clear of the lifted loads and never be under, on or near suspended loads. When using slings, no part of the body should be placed between the sling and load, or between the sling and lifting hook. In addition, personnel must be alert to the potential for the sling to become snagged during a lift. Never use a roundsling to pull on objects in a snagged or constrained condition.

6. Properly Store and Maintain Slings

In order to prevent damage to slings when not in use, you should store slings in a cool, dry and dark location. Slings should be stored in an area free from environmental or mechanical sources of damage, such as: weld spatter, splinters from grinding or machining, heat sources, chemical exposure, etc. Also, keep slings clean and free of dirt, grime and foreign materials. If roundslings are cleaned, use only mild soap and water. Rinse sling thoroughly and allow to dry completely before placing the sling back into storage or use. Do not machine wash slings. Machine washing results in significant loss of sling strength.

Where to Find Additional Information

This bulletin does not provide you with all the information you need to know in order to be considered trained and knowledgeable about rigging and lifting loads, but it does provide important information about the use of web slings within a rigging system. If you need more information about web slings and rigging practices or your responsibilities according to regulations and standards, talk to your employer. You and your employer can consult a number of sources o­n formation to help ensure that you are properly trained and knowledgeable when using web slings, including (but not limited to):

  • WSTDA-WS-1—Recommended Standard Specifications for Synthetic Web Slings
  • WSTDA-WS-2—Recommended Operating and Inspection Manual for Synthetic Roundslings
  • ASME B30.9—Synthetic Webbing Slings: Selection, Use and Maintenance
  • OSHA 29 CFR 1910.184—Slings.
  • Rigging handbooks.
  • OSHA Guidance on Safe Sling Use (https://www.osha.gov/dsg/guidance/slings/synth-web.html)
  • Manufacturer’s catalog, manual, website, bulletins, etc
  • Formal training provided by manufacturers or other outside entities

Crosby General Warning

All products manufactured by The Crosby Group LLC, are sold with the express understanding that the purchaser is thoroughly familiar with the safe and proper use and application of the product.

Responsibility for the use and application of the products rests with the user. The Crosby Group disseminates products warnings and end user application information through various channels. In addition, Crosby provides formal product training seminars and our engineering personnel are readily available to answer your technical questions. For more information read the Crosby General Catalog, refer to Crosby’s web site @ www.thecrosbygroup.com, and contact your Crosby distributor or Crosby direct at 918-834-4611.

Failure of the product can occur due to misapplication, abuse, or improper maintenance. Product failure could allow the load to become out of control, resulting in possible property damage, personal injury or death.

There are numerous government and industry standards that cover products made by Crosby. This catalog makes no attempt to reference all of them. We do reference the standards that are most frequently asked about.

Ratings shown in Crosby Group literature are applicable only to new or “in as new” condition products.

Load Limit ratings indicate the greatest force or load a product can carry under usual environmental conditions. Shock loading and extraordinary conditions must be taken into account when selecting products for use in a system.

In general, the products displayed in Crosby Group literature are used as parts of a system being employed to accomplish a task. Therefore, we can only recommend within the Working Load Limits, or other stated limitations, the use of products for this purpose.

The Working Load Limit, or Design Factor, or Efficiency Rating of each Crosby product may be affected by wear, misuse, overloading, corrosion, deformation, intentional alteration, and other use conditions. Regular inspection must be conducted to determine whether use can be continued at the catalog assigned WLL, a reduced WLL, or whether the product must be withdrawn from service.

Crosby Group products generally are intended for tension or pull. Side loading must be avoided, as it exerts additional force or loading which the product is not designed to accommodate.

Welding Crosby load support parts or products can be hazardous. Knowledge of materials, heat treatment, and welding procedures are necessary for proper welding. Crosby Group should be consulted for information.

The assigned Ultimate Load Rating of Crosby Group products for the reeving of wire, manila, or synthetic rope is based upon design; the catalog ultimate strength for the rope parts, when totaled, may exceed the assigned Ultimate Load Rating.

The Working Load Limit of a sling must not exceed the lowest Working Load Limit of the components in the system.

The recommended Proof Load on all items in this catalog is 2 times the Working Load Limit unless otherwise shown.

Products that Crosby intends for swaging are identified in this catalog. For proper swaging machine training, operations and die selection, refer to specific product section in this manual. To develop other product for swaging requires knowledge of materials, heat treatment, product design, die design and performance of the final product.

Use only new genuine Crosby parts as replacements when servicing or repairing Crosby products.

Crosby products are to be considered as sparking, unless otherwise noted.

Product Label Replacement – In accordance with ANSI535.4-1991, “Product Safety Labels” should be periodically inspected and cleaned. “Product Safety Labels” should be replaced when they are no longer legible. Current Crosby warning and application labels, for applicable products, are available from The Crosby Group LLC.

Two decimal and fractional dimensions shown in catalog are intended as nominal dimensions only. If three decimal dimensions are shown, contact Crosby for tolerance information.

Low Temperature Service

Crosby forged and cast steel products can be used in general service conditions down to temperatures of -40° F (-40° C). McKissick blocks can be used in general service conditions down to temperatures of -4° F (-20° C).  At temperatures from 0° F to -40° F (-18° C to -40° C), good rigging practice requires special attention in the following areas.

  1. Lifting should be performed at a steady rate. Shock loading should be avoided.
  2. Equipment containing bearings should have increased inspection and maintenance schedule, and may require special lubrication.
  3. All lifting equipment should be given a thorough visual inspection before each lift.
  4. Remove nicks, gouges, or cracks by grinding (5% maximum material removal).
  5. Do not use fittings that have been welded or modified after leaving the factory.
  6. If determined to be necessary by the user, lifting equipment should undergo periodic inspection by dye penetrant or magnetic particle  surface inspection.

For operation at temperatures below -40° F (-40° C), consider “Cold Tuff” products or contact Crosby Engineering.

Elevated Temperature Service

Crosby forged and cast steel products can be used in general service conditions up to temperatures of 400° F (204° C). The following should be considered when operating up to temperatures of 400 ° F (204° C).

  1. Products that contain non-ferrous materials, and lubricants, plastics, etc. may be adversely affected by high temperatures, and typically should not exceed 200° F (93° C).
  2. Galvanized, plated or painted fittings may suffer some or total degradation of the surface finish.
  3. Extended exposure to elevated temperatures can cause severe surface scaling and significant permanent reduction of properties.
  4. Repeated heating and cooling to room temperatures can result in temper embrittlement For other operating temperatures or products, contact Crosby Engineering.

Specific warning and application instructions are included in the Crosby catalog. The instructions can be found at the end of each product section. The symbol shown to the right can be found on the page for products that have application instructions included in the Crosby catalog. The page numbers that the specific product information can be found are shown in the box for easy reference.

Slingmax Twin-Path Inspection

Inspections of Twin-Path® Products

  1. Check-Fast® External Warning Indicator (EWI) and Tell-Tail indicators shall extend past the tag area of each sling. If your sling is equipped with Check-Fast® and the EWI is not visible or both Tell-Tails are not visible, remove the sling from service. Send to manufacturer for repair evaluation.
  2. If Fiber Optic Inspection is installed in the sling, inspect by allowing light to enter the fiber optic cable. If the fiber optic cable does not transmit light from end to end, remove the sling from service and contact the manufacturer for repair evaluation.
  3. Slings shall be inspected for evidence of cutting or tearing of the outer cover. Slings with cuts shall be removed from service and sent back to the manufacturer for repair evaluation. Damage to the cover may indicate core damage.
  4. Inspect slings for evidence of heat damage. Sparkeater® slings shall not be exposed to temperatures over 300°F/150°C. Slings made with K-Spec® core yarn or polyester shall not be exposed to temperatures above 180°F/82° Cold temperature exposure down to -40°F/-40°C does not affect the strength of the products.
  5. If any part of the sling shows evidence of chemical degradation or damage, remove the sling from service. Return the sling to the manufacturer for repair to the manufacturer for repair evaluation
  6. Slings using aluminum fittings shall not be used where fumes, vapors, sprays, or mists of alkalis or acids are present
  7. Twin-Path® slings and any fittings attached shall be subjected to frequent and regular inspections. In addition to the initial inspection by a competent person and frequent written inspections, the slings shall be visually inspected before each use.
  8. Written inspections shall be performed as required and documents of such inspection by a competent person shall be kept on file in the safety department of the plant or site where used. Inspections may be performed more often based on frequency of use, severity of conditions, and experience of past service life.
  9. Slings shall be examined throughout their length for abrasion, cuts, heat damage, fitting distortion or damage, and tag legibility. If the inspector has any doubts, the sling shall be removed from service. If deterioration is found, the sling must be removed from service.
  10. Slings removed from service that are not repairable shall be destroyed and rendered completely unfit for future use.
  11. Abrasion, heat damage, or cuts to the cover may indicate a loss of strength to the core yarns, and these slings shall not be used until evaluated by the manufacturer.

Test Procedures for Twin-Path® Sling Products

  1. Proof tests shall consist of pulling the slings to twice their rated capacity.
  2. Testing of Twin-Path® sling products and core yarn shall be performed on a testing machine that meets or exceeds the standards as described in ASTM E-4.
  3. Break testing of slings shall be as above with results documented. Pin size for break testing should be of a diameter equal to half the nominal sling width, or larger.
  4. Repaired fittings or slings shall be proof-tested before they are returned to service. Certifications may be provided to the fitting or sling owner.

Slingmax Mechanical Considerations

  1. Load both paths of Twin-Path® slings equally. Do not side load. Do not load the edge of the sling.
  2. Determine the weight of the load. The weight of the load shall be within the rated capacity of the sling.
  3. Select a sling having suitable characteristics for the type of load hitch and environment.
  4. Slings shall not be loaded in excess of the rated capacity. Consideration shall be given to angle of lift which may affect the lifting capacity. Diameters of pins and edges also may affect the capacity of the lifting sling.
  5. Slings used in a choker shall not be forced to tighten around the load by pounding with hammers or other objects. Choker hitches are the least effective way to use a sling based on capacity. Two chokers should be used to balance the load. One choker in the center of the load may create an unbalanced situation which could lead to an accident.
  6. Slings used in a basket hitch must have the load balanced to prevent slippage and accidents
  7. Slings used with fittings shall be compatible with the fittings used. The lifting capacity shall be rated at the lower of the lifting or sling. Fitting openings shall be the proper shape and size to assure that the sling will seat properly.
  8. Slings in contact with edges, corners, protrusions, or abrasive surfaces shall be protected with a material of sufficient strength, thickness, and construction to prevent damage. The pin area of a shackle can cause synthetic slings to cut or tear.
  9. Slings shall not be dragged on the floor or drawn across other surfaces which may damage the sling.
  10. Slings shall not be twisted or tied in knots to shorten.
  11. Slings can be damaged by resting loads on them or by pulling slings from under a load.
  12. Do not drop objects on slings or run over them with vehicles.
  13. Slings which are damaged shall not be used.
  14. Sling hitches must provide control of the load.
  15. Portions of the human body shall be kept from between the sling and the load and from between the sling and any attachment to lifting devices such as hooks.
  16. Personnel shall stand clear of suspended loads.
  17. Personnel shall not ride on the sling or suspended loads.
  18. Avoid shock loading.
  19. Twisting and kinking the legs of the sling shall be avoided.
  20. Load applied to the hook should be centered in the bowl of the hooks. Do not point-load the hook.
  21. During lifting with or without the load all personnel shall be alert for possible snagging.
  22. The slings shall contain or support the load from the slides above the center of gravity so the load will not tilt when the load is lifted.
  23. Synthetic roundsling users shall be trained in the selection, inspection, cautions to personnel effects of environment, and rigging practices.
  24. Only legibly marked or labeled slings must be used. If the tag is not legible, or missing, the sling must not be used.
  25. Keep labels or tags away from the load the hook and the angle of choke.
  26. Synthetic slings should be inspected before each lift.

Slingmax Environmental Considerations

K-SPEC® core yarn strength retention is based on test results of components at 65°C/150°F (or less) for 6 months. K-SPEC® has a 100% strength retention when exposed to: age, 10% detergent solution, rot and mildew, sunlight and toluene; 99% strength retention when exposed to: acetic acid, gasoline, hydrochloric acid 1m, hydraulic fluid, kerosene, and sea water; 98% retention when exposed to: 25% ammonium hydroxide, 10% hypophosphite solution, and 40% phosphoric acid; 97% retention when exposed to 5m sodium hydroxide; 95% retention when exposed to Portland cement and sulfuric acid; and 88% retention when exposed to Clorox bleach, and nitric acid.