Slings
A comprehensive library of technical data for the selection and use of rigging slings. This resource provides verified insights into design factors, rated load calculations, and mandatory identification requirements to ensure compliance with Alberta OH&S legislation and ASME B30.9 Standards. Beyond Technical specs, common industry misconceptions to clarify complex rigging regulations are addressed.
Key Focus Areas:
- Identification: Requirements for mandatory tags and rated load markings.
- Inspections: Requirements for initial, frequent, and periodic assessments.
- Environmental Limits: Guidelines for temperature and chemical exposure.
- Rigging Practices: Critical data on hitch configurations and load control.
The following information is compliant with ASME B30.9 Slings.
For more detailed information, please refer to the full ASME standard.
General Information
TRAINING
All users of slings must receive training in the following areas:
- Selection of appropriate sling types and configurations
- Inspection procedures and identification of removal criteria
- Personnel safety precautions during handling and use
- Environmental effects on sling performance (e.g., temperature, chemical exposure)
- Proper rigging practices to ensure safe and effective load handling
Employers and Supervisors looking for help determining the competency of trained riggers, click here.
DESIGN FACTORS
Synthetic Web slings, Polyester Roundslings and Wire Rope slings must have a minimum design factor of 5.
Alloy steel chain slings must have a minimum design factor of 4.
RATED LOADS
The term rated load is also known as, Working Load Limit (WLL), Safe Working Load (SWL) and Capacity.
(a) The manufacturer is responsible for determining the rated load of the sling.
(b) At a minimum, this rated load must take into account the following factors:
(1) Strength of individual components
(2) Total number of legs
(3) Design factor
(4) Type of hitch used
(5) Angle of loading
(6) Fabrication efficiency (Only for web slings, polyester roundsling and wire rope slings)
(7) Connecting hardware size and shape (Only for web slings, polyester roundsling and wire rope slings)
(c) For quadruple-leg or double-basket slings, the rated load must not exceed that of a triple-leg sling (Only for chain slings)
SLING IDENTIFICATION
Identification Requirements
Each sling must be marked to show:
(a) Manufacturer’s name or trademark, or if repaired, the entity doing the repairs
(b) Rated load for at least one hitch type and the angle it is based on
(c) Number of legs in the sling assembly
(d) Diameter or size (only for chain)
(e) Manufacturer’s code or stock number (Only for web slings and polyester roundslings)
(f) Core material (Only for polyester roundslings)
(g) Cover material, if different from the core material (Only for polyester roundslings)
EFFECTS OF ENVIRONMENT
Temperature.
Chain slings must not be used at temperatures above 204°C (400°F) or below -40°C (-40°F) without consulting the sling manufacturer.
Wire Rope Slings with IWRC must not be used at temperatures above 204°C (400°F) or below -40°C (-40°F) without consulting the sling manufacturer.
Wire Rope Slings with Fiber core must not be exposed to temperatures in excess of 82°C (180°F) without consulting the sling manufacturer.
Web and Polyester Roundslings must not be used in contact with an object or at temperatures in excess of 90°C (194°F) or below -40°C (-40°F).
Chemically Active Environment
Chemically active environments can degrade the strength of all slings. This includes exposure to chemicals in the form of solid, liquid, gas, vapor, or fumes. Before using slings in such conditions, consult the sling manufacturer or a qualified person.
Inspections & Removal Criteria
All inspections must be carried out by an authorized individual. If any deficiencies are found, they must be assessed by a qualified individual to determine whether they pose a hazard. If a hazard is confirmed, appropriate corrective actions must be identified and implemented.
Initial inspection
Before use, all new, altered, modified, or repaired slings must be inspected by a designated person to verify compliance with applicable standards.
Initial inspections do not require written records. For alloy steel chain slings, written records are required and must reference the individual sling identification.
Frequent Inspection
(a) Each shift before a sling is used, a visual inspection for damage must be conducted. Slings used in severe or special service should be inspected before every use.
(b) Slings must be removed from service if any condition exists that may pose a hazard or raise concerns about its safety.
(c) Frequent inspections do not require written records.
Periodic Inspections
(a) A thorough inspection of the sling for damage must be periodically carried out by an authorized person.
For chain slings each link and component should be examined one by one, with particular attention paid to exposing and inspecting all surfaces, including the inner surfaces of links. For wire rope slings inspect all splices, end attachments and fittings.
The sling must be evaluated for any conditions noted under “Removal Criteria”, and a determination made as to whether or not they constitute a hazard.
(b) Frequency of Periodic Inspections: These inspections must occur at intervals no greater than one year. The frequency of these inspections should be based on
(1) How often the sling is used
(2) The severity of the operating conditions
(3) The nature of the load-handling activity
(4) Insights based on the observed service life of similar slings in comparable environments
(c) Suggested Inspection Intervals:
(1) Normal service – yearly
(2) Severe service – monthly to quarterly
(3) Special service – as recommended by a qualified person
(d) Documentation confirming completion of the most recent periodic inspection must be maintained.
(e) For chain slings a written record of the most recent periodic inspection must be kept which includes the condition of the sling.
Removal Criteria
(see ASME B30.9 for full details)
A sling must be removed from service if conditions such as the following are present,
(a) Missing or illegible sling identification
(b) Signs of heat damage
(c) For hooks, removal criteria as stated in hook section
(d) For hardware, removal criteria as stated in hardware section
(e) Any other visible damage, or condition that causes doubt as to the continued use of the sling
Additional for Alloy Steel Chain Slings
(a) Chain links or components (except hooks)-that are cracked, bent or broken must not be repaired; they must be replaced.
(b) Do not use a mechanical coupling link for repairs within the body of an alloy chain sling unless it is a direct replacement for a link originally approved by the manufacturer or a qualified individual.
Additional for Wire Rope Slings
(a) The wire must not be repaired.
(b) Repairs are limited to end attachments only
Additional for Web Slings
(a) Repairs to load-bearing splices are not permitted.
(b) Temorary repairs to sling or fittings are not permitted
Additional for Polyester Roundslings
(a) Repairs to load-bearing yarns are not permitted.
(b) Temorary repairs to sling or fittings are not permitted
Rigging Practices
Sling Selection
(a) Slings that appear to be damaged must not be used unless inspected and deemed safe to use by a qualified person.
(b) Slings must be selected based on their suitability for the specific load type, hitch configuration, and environmental conditions,.
(c) The sling’s rated load must not be exceeded. For muli-leg slings, no leg must be loaded above the single-leg rating.
(d) When a choker hitch is not identified on the sling tag, the choker hitch rating must be calculated as 80% of the sling’s straight-line rating, except for wire rope slings which must be calculated at 75%. (see ASME B30.9 for specific details)
(e) In a choker hitch, the rated load for angles of choke that are less than 120 degrees should not be used without reducing the rated load. Consult the sling manufacturer or a qualified person.
(f) When using multiple-leg slings to lift nonsymmetrical loads, a qualified person must do an analysis to ensure that no single leg is overloaded.
(g) Multiple-leg slings must be selected according to the rated load corresponding to the specific sling angles shown on the identification tag. If used at angles not specified, the rated load must be verified by the manufacturer or a qualified person.
(h) Slings must not be used at horizontal sling angles less than 30 degrees except as permitted by the manufacturer or qualified person.
(i) When a sling leg is configured as a basket hitch—where the lower connector (hook) attaches to the master link—the basket hitch must be rated no higher than its single-leg capacity, unless the master link is engineered to safely support this arrangement
(j) Fittings must be of the correct shape and size to properly seat in the hook, shackle or other lifting device.
(k) Chain Slings only – The rated load of a basket hitch must be decreased when D/d ratios smaller than 6/1 are used. Consult the sling manufacturer or qualified person.
(l) Wire Rope sling only – The rated load of a basket hitch must be decreased when D/d ratios smaller than 25/1 are used. Consult the sling manufacturer or qualified person.
(m) Polyester Roundsling only – The rated capacity of a polyester roundsling may need to be reduced depending on the size and shape of any attached fittings or lifting devices.
(n) Synthetic Web slings and Polyester Roundslings must not be used to support suspended personnel platforms
Cautions to Personnel
(a) Keep all parts of the body clear of areas between the sling and the load, as well as between the sling and the crane or hoist hook.
(b) Personnel must avoid positioning themselves in line with or adjacent to sling legs that are under tension.
(c) Never stand beneath or walk under a suspended load.
(d) Riding on the sling is strictly prohibited.
Effects of Environment
Slings must be stored in a location that protects them from mechanical damage, corrosion, moisture, extreme temperatures, and kinking.
Rigging Practices
(a) Only shorten or adjusted slings by methods approved by the sling manufacturer or a qualified person.
(b) Never shorten or lengthen a sling by knotting or twisting.
(c) The slings must be hitched in a manner that provides control of the load.
(d) For Synthetic Web slings and Polyester Roundslings, suitable protection must be used whenever the sling comes in contact with edges, corners, or protrusions to prevent sling damage. For Alloy Steel Chain slings and Wire Rope slings, appropriate protection should be used to prevent damage to the sling.
(e) Avoid shock loading.
(f) Do not allow loads to rest on the sling.
(g) Do not pull a sling out from under a load that is resting on the sling.
(h) Avoid twisting and kinking slings.
(i) Be alert for possible snagging while lifting, whether a load is attached or not.
(j) When using multiple basket or choker hitches, rig the load to prevent the slings from slipping or sliding along the load.
(k) When a basket hitch is used the legs of the sling should support or contain the load from the sides, above the centre of gravity, so the load remains under control.
(l) Do not drag slings on the floor or over an abrasive surface.
(m) For choker hitches, the choke point should only be on the sling body, never on a fitting.
(n) For choker hitches, an angle of choke less than 120 degrees should not be used without derating the sling.
(o) Slings should not be constricted, bunched, or pinched by the load, the hook, or any splice or fitting.
(p) The load must be applied to the hook so that it is centred in the base (seat or saddlel) of the hook to prevent point loading on the hook, unless the hook is specifically designed for point loading.
(q) Web slings only – An object placed in the eye of a sling should not be wider than one-third (⅓) of the eye length.
(r) Wire Rope slings only – An object placed in the sling eye should not be wider than half of the length of the eye, and no smaller than the sling’s nominal diameter.
(s) Alloy Steel Chain slings only – Mechanical links should not bear directly on the load, hook, or other fitting when used to join chain links in an endless sling.
For additional requirements see ASME B30.9
Misconceptions
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If you have attended a training course you are a competent rigger.
Training is only one factor in being competent to carry out rigging tasks without supervision. You must also be qualified and have sufficient experience to work safely on your own.
Referenced Standards:
ALBERTA OHS ACT
1(d) “competent” in relation to a person, means adequately qualified, suitably trained and with sufficient experience to safely perform work without supervision or with only a minimal degree of supervision
(3)(a) If work is to be done that may endanger a worker, the employer must ensure that the work is done by a worker who is competent to do the work.
Training
Workers using Alloy Steel Chain slings must be trained in the proper selection, inspection and usage. This includes being aware of potential impacts to their work environment or fellow workers.
Refer to the ASME Standard B30.9 – 2025 Chapter 9-1 Alloy Steel Chain Slings for more detailed information.
A sling's capacity stays the same when used around an edge or corner.
Alloy steel chain slings are greatly effected when used around an edge or corner. Wrapping a chain around a 90 degree corner applies point loading on the links and can cause damage or failure of the chain. Also, using chain around a small radius will reduce the weight capacity that the sling can lift. Riggers must know what the minimum radius or D/d ratio recommended by the manufacturer is before using a sling in this situation.
Referenced standards:
ALBERTA OHS CODE
12 An employer must ensure that equipment or PPE is of sufficient size, strength and design, made of suitable materials, to withstand the stresses imposed on it during operation and to perform the function for which it was designed.
296 An employer must ensure that sharp edges on loads to be hoisted are guarded to prevent damage to slings or straps of the rigging.
SLING SELECTION:
- Selection Criteria
Choose slings suitable for the load type, hitch, and environment as per Sections 9-1.5 and 9-1.8. - Load Limits
Do not exceed the sling’s rated load. For multi-leg slings, no leg should exceed its single-leg rating. - Choke Hitch Ratings
If not specified, assume choke hitch rating = 80% of straight-line rating unless otherwise provided by manufacturer or qualified person. For choke angles <120°, ratings must come from manufacturer or qualified person. - Basket Hitch Ratings
Reduce rated load when D/d ratio <6 (refer to Table 9-1.10.1-1 or consult manufacturer/qualified person). - Multi-Leg Sling Use
For nonsymmetrical loads, a qualified person must analyze to prevent overloading. Select based on rated load for specific angles; other angles require manufacturer or qualified person guidance. - Angle Restrictions
Do not use slings at angles <30° unless approved by manufacturer or qualified person. - Special Configurations
When a sling leg forms a basket hitch with the hook attached to the master link, limit rating to single-leg rating unless master link is rated for that setup. - Component Fit
Components must be the correct shape and size to seat properly in hooks or lifting devices.
For more detailed requirements, refer to the ASME Standadard B30.9-2025 Chapter 9-1 Alloy Steel Chain Slings
If you have attended a training course you are a competent rigger.
Training is only one factor in being competent to carry out rigging tasks without supervision. You must also be qualified and have sufficient experience to work safely on your own.
Referenced Standards:
ALBERTA OHS ACT
1(d) “competent” in relation to a person, means adequately qualified, suitably trained and with sufficient experience to safely perform work without supervision or with only a minimal degree of supervision
(3)(a) If work is to be done that may endanger a worker, the employer must ensure that the work is done by a worker who is competent to do the work.
Training
Workers using wire rope slings must be trained in the appropriate selection, inspection and usage. Including potential impacts to the work environment and other workers.
Refer to the ASME Standard B30.9-2025 Chapter 9-2 Wire Rope Slings for more detailed information.
A sling's capacity stays the same when used around an edge or corner.
Wire rope slings are greatly effected when wrapped around a 90 degree corner. This is called point loading and can cause damage or failures to the wire rope. Additionally, use of wire rope around a small radius reduces the weight capacity of the sling. Refer to the manufacturer’s guidelines for the minimum radius or D/d ratio recommended.
Referenced Standards:
Alberta OHS Code
296 An employer must ensure that sharp edges on loads to be hoisted are guarded to prevent damage to the slings or straps of the rigging.
SLING SELECTION: Condition & Inspection
Do not use slings that appear damaged unless inspected and approved per Section 9-2.9.
- Proper Selection
Choose slings suitable for the load type, hitch, and environment. Never exceed the sling’s rated load; for multi-leg slings, each leg must stay within its single-leg rating. - Choker Hitch Ratings
If not marked, assume:
Single-leg & bridle slings: 75% of straight-line rating.
Cable-laid slings: 70%.
For grommet/endless slings, consult manufacturer or qualified person. - Angles & Load Distribution
For choke angles <120°, use ASME Table 9-2.10.1-1 or consult manufacturer. For multi-leg slings with nonsymmetrical loads, a qualified person must analyze to avoid overload. Select multi-leg slings based on rated load at specified angles; other angles require manufacturer guidance. - D/d Ratio & Angle Limits
If D/d ratio is below 15:1 (hand-tucked splice) or 25:1 (mechanical splice/swaged), reduce rated load per manufacturer or Wire Rope Sling Users Manual. Do not use slings at angles <30° unless approved by manufacturer or qualified person. - Special Configurations & Fittings
Basket hitch using master link: limited to single-leg rating unless master link is rated for that setup. Fittings must fit properly in hooks, shackles, or other connectors.
For more detailed information, refer to the ASME Standard B30.9 – 2025 Chapter 9-2 Wire Rope Slings.
Any size object can be used in the eye of a Wire Rope Sling where no thimble is present.
An object in the eye of a wire rope sling should not be wider than 1/2 the length of the eye, nor less than the nominal sling diameter.
Referenced Standards:
RIGGING PRACTICES:
- Avoid Constriction
Slings should not be pinched, bunched, or constricted by load or fittings. - Hook & Eye Guidelines
Load should be centred in hook bowl (unless hook is designed for point loading). Object in sling eye: width ≤ ½ eye length and ≥ sling diameter.
Refer to the ASME Standard B30.9-2025 Chapter 9-2 Wire Rope Slings for more detailed information.
If you have attended a training course you are a competent rigger.
Training is only one factor in being competent to carry out rigging tasks without supervision. You must also be qualified and have sufficient experience to work safely on your own.
Referenced Standards:
ALBERTA OHS ACT
1(d) “competent” in relation to a person, means adequately qualified, suitably trained and with sufficient experience to safely perform work without supervision or with only a minimal degree of supervision
(3)(a) If work is to be done that may endanger a worker, the employer must ensure that the work is done by a worker who is competent to do the work.
TRAINING
Workers using synthetic webbing slings must be trained in the proper selection, inspection and usage. Including understanding potential impacts to the work environment and other workers.
Refer to the ASME Standard B30.9-2025 Chapter 9-5 Synthetic Webbing Slings for more detailed information.
A sling's capacity stays the same when used around an edge or corner.
Synthetic web slings are greatly effected when wrapped around a 90 degree corner. This is called point loading and can cause damage to the sling fibres or cause the webbing to fail. When using synthetic web slings around a small radius, the weight capacity of the sling must be reduced.
Referenced Standards:
Alberta OHS Code
296 An employer must ensure that sharp edges on loads to be hoisted are guarded to prevent damage to the slings or straps of the rigging.
SLING SELECTION:
- Proper Selection:
Choose slings suitable for load type, hitch, and environment. - Load Limits:
Never exceed the sling’s rated load. For multi-leg slings, no leg should exceed its single-leg rating. - Choker Hitch:
If rating is not specified, assume choker hitch = 80% of straight-line rating. For choke angles <120°, use ASME Table 9-5.10.1-1 or consult manufacturer/qualified person. - Multi-Leg Slings:
For nonsymmetrical loads, a qualified person must analyze to prevent overload. Select based on rated load for specific angles; other angles require manufacturer guidance. - Angle Restrictions:
Do not use slings at angles <30° unless approved by manufacturer or qualified person.
For more detailed information, refer to the ASME Standard B30.9-2025 Chapter 9-5 Synthetic Webbing Slings.
Synthetic Web Slings are not affected by water.
Water absorption can decrease the strength of nylon synthetic webbing by as much as 15%. (Once dried completely the sling’s full strength returns.)
Any size object can be used in the eye of Synthetic Webbing Slings.
An object in the eye of a synthetic webbing sling should not be wider than 1/3 the length of the eye.
Referenced Standards:
RIGGING PRACTICES
- Avoid Constriction:
Slings should not be bunched, pinched, or constricted by load, hook, or fittings. - Hook Loading:
Load should be centred in the hook bowl unless hook is designed for point loading. - Eye Size:
Object in sling eye should be ≤ one-third of eye length.
Refer to the ASME Standard B30.9-2025 Chapter 9-5 Synthetic Webbing Slings for more detailed information.
Synthetic Webbing Slings can be cleaned with water.
Do not wash synthetic web slings. As well as a reduction in strength, mechanical and chemical damage can result.
If you have attended a training course you are a competent rigger.
Training is only one factor in being competent to carry out rigging tasks without supervision. You must also be qualified and have sufficient experience to work safely on your own.
Referenced Standards:
ALBERTA OHS ACT
1(d) “competent” in relation to a person, means adequately qualified, suitably trained and with sufficient experience to safely perform work without supervision or with only a minimal degree of supervision
(3)(a) If work is to be done that may endanger a worker, the employer must ensure that the work is done by a worker who is competent to do the work.
TRAINING
Workers using polyester roundslings must be trained in the proper selection, inspection and usage. Including potential impacts on the work environment or other workers.
Refer to the ASME Standard B30.9-2025 Chapter 9-6 Polyester Roundslings for more detailed information.
A sling's capacity stays the same when used around an edge or corner.
Polyester Roundslings are greatly effected when wrapped around a 90 degree corner. This is called point loading and can cause damage to the internal fibres or cause the sling to fail. When using Polyester Roundslings around a small radius, the weight capacity of the sling must be reduced. Refer to the manufacturer’s guidlines to determine the minimum radius or D/d ratio recommended.
Referenced Standards:
Alberta OHS Code
296 An employer must ensure that sharp edges on loads to be hoisted are guarded to prevent damage to the slings or straps of the rigging.
SLING SELECTION:
- Proper Selection:
Choose slings suitable for load type, hitch, and environment. - Load Limits:
Never exceed the sling’s rated load. For multi-leg slings, no leg should exceed its single-leg rating. - Choker Hitch:
If rating is not specified, assume choker hitch = 80% of straight-line rating. For choke angles <120°, use ASME Table 9-6.10.1-1 or consult manufacturer/qualified person. - Multi-Leg Slings:
For nonsymmetrical loads, a qualified person must analyze to prevent overload. Select based on rated load for specific angles; other angles require manufacturer guidance. - Angle Restrictions:
Do not use slings at angles <30° unless approved by manufacturer or qualified person.
For more detailed information, refer to the ASME Standard B30.9-2025 Chapter 9-6 Polyester Roundslings, and the WSTDA-RS-1 Section 4.7.
When attaching Polyester Roundslings to a load using shackles or other connecting devices, the diameter used within the sling does not matter as long as the capacities are equal to the sling's rating.
The strength of a polyester roundsling is affected by the size/diameter of the connection hardware. Reference the relevant manufacturer guidelines to assess the appropriate minimum diameter allowed for the capacity of the sling being used.
Referenced Standards:
SLING SELECTION:
Fittings:
Must fit properly in hooks, shackles, or other devices. Rated load may need reduction based on fitting size/shape. Hardware must comply with WSTDA-RS-1 Section 4.7 or manufacturer guidance.
For more detailed information, refer to the ASME Standard B30.9-2025 Chapter 9-6 Polyester Roundslings, and the WSTDA-RS-1 Section 4.7.
Polyester Roundslings can be wrapped around chamfered (beveled) corners.
Polyester Roundslings shall not contact edges that are chamfered or flattened at an angle unless the edges conform to edge radius requirements.
Referenced Standards:
RIGGING PRACTICES
- Protection:
Protect slings from edges, corners, protrusions, abrasive surfaces, or hardware with adequate padding unless edges are rounded per WSTDA-RS-1 Section 4.6 or manufacturer guidance. - Handling:
Do not rest loads on slings or drag slings on floors/abrasive surfaces. Do not pull slings from under a load while it’s resting on them. - Avoid Constriction:
Slings should not be bunched, pinched, or constricted by load, hook, or fittings. - Alertness:
Personnel must watch for snagging during all load-handling activities.
For more detailed information refer to the ASME Standard B30.9-2025 Chapter 9-6 Polyester Roundslings and the WSTDA-RS-1 Section 4.6.
Questionnaires
Suppliers and Employers are equally responsible for ensuring the products supplied to and used at the job site are compliant with industry and legislative standards. Click on the appropriate questionnaire below when acquiring information from the supplier or manufacturer for each of the specified products.
Refer to Alberta OHS Act – Obligations of Worksite Parties and the applicable ASME B30.9 Standards.