Rigging and Lifting Slings | Training Tuesday

industrial rigging and lifting sling being sewn

There’s a lot of different terminology and rules to remember about synthetic rigging and lifting slings – but Hercules SLR has you covered. 

When you think of a heavy duty sling, you might wonder why a rigger would choose a synthetic material over something ‘heavy duty’, like chain. They exist for a reason—Some benefits of synthetic rigging and lifting slings include: 

  • Economical
  • Flexible/Easy-to-store
  • Great for applications where steel or wire rope slings could damage a delicate load. 

RIGGING AND LIFTING SLINGS | WHAT THEY’RE MADE OF

Synthetic slings, or textile slings are made out of fabricated materials like nylon or polyester. Colour codes are used to identify the synthetic sling’s material. The colour is identified by a label on rigging and lifting slings – These are: 

  • BLUE: Polyester (ES) 
  • GREEN: Polyamide (PA)
  • BROWN: Polypropylene (PP) 

In terms of their construction, synthetic slings are often known as web slings or round slings. 

RIGGING AND LIFTING SLINGS | SAFETY TIPS

There are many safety tips to keep in mind when lifting with synthetic slings. Here are a few simple safety tips and tricks to keep in mind:

  • Store synthetic slings in a cool, dry place that’s free from exposure to ultra-violet light, like sunlight. 
  • Never pull your sling from under a load 
  • If the tags/labels are unreadable, don’t use the sling 
  • Be careful when using the sling around sharp corners or edges—Sharp corners can tear the synthetic sling 

RIGGING AND LIFTING SLINGS | INSPECTON

Synthetic slings should be inspected on a semi-regular basis. There are three types of inspection you must do with your synthetic sling(s)—These are: 

1) INITIAL INSPECTION

Before using your synthetic sling, a designated person or the user must check the sling to make sure it’s the correct to use for the application, and to ensure the sling meets the manufacturer’s specifications. A designated person is someone who has a recognized degree or certificate in an applicable field (like rigging) or someone who has extensive knowledge, training, experience and has successfully demonstrated the ability to solve or resolve problems that relate to the application.

This inspection should happen whether the sling is new, repaired or altered in any way. 

2) FREQUENT VISUAL INSPECTION 

Whoever is handling the sling, should conduct a visual inspection(s) each time it’s used. Further conditions for frequent visual inspection is:

A) A visual inspection for damage shall be performed by the user or other designated person each date or shift the sling is used. 

B) If the sling has any conditions that could cause hazard, the sling should be removed from service and not returned until it’s been approved by a designated person. 

3) PERIODOC INSPECTION 

Each part of the sling must be inspected individually—Take care to expose and examine all surfaces and individual component. 

Periodic inspections should not exceed one year—Inspect your synthetic sling at least once annually. Inspection frequency is based on how often slings are used, the kind of lifts being made, experience gained on service life of slings and how severe service conditions are.

Severe service conditions are defined as: 

  • Normal service—Yearly
  • Severe service—Monthly to quarterly
  • Special service—This is recommended by a qualified person 

When you inspect your sling, look for these conditions: 

  • Bent or twisted fittings 
  • Chemical damage
  • Crushing or knots 
  • Cuts and broken stitching 
  • Exposed internal cover due to cut or abrasion 
  • Heat damage 
  • Holes, cuts, tears or snags 
  • Missing or illegible sling identification
  • Severe abrasion
  • Twin path tell-tails not extending 1/2″ past the tag area 
  • Ultra-violet ray damage
  • Worn or broken stitching 

rigging and lifting synthetic web slings and orange synthetic round sling

 

 

 

 

 

 

 

 

 

RIGGING AND LIFTING SLINGS | KNOW YOUR ANGLES 

What do we mean when we discuss sling angles? Sling angle is the space where the sling and the horizontal part of the load meet. 

Rated capacity, rated load or working load limit refers to the maximum working load that the sling manufacturer says the sling can hold. The terms ‘rated capacity’ and ‘working load limit’ are commonly used to describe rated load. The angle is important as the sling angle creates tension, which can impact the rated capacity of the sling.

Safe sling angles are typically 45­° greater from the horizontal point of the load. 

When we talk about sling angles, it’s important to talk about sling hitches. Hitches refer to the different way a sling can be applied to a load. The angle of multi-leg slings will effect the rated capacity of the bridle or multi-leg sling.

The most common types of hitches found in rigging are: 

  • VERTICAL: Method of rigging a web sling where the load’s attached to one end of the web sling, and the other end of the web sling is attached to the lifting device. 
  • CHOKER: Method of rigging a web sling in which the web sling is passed around the load, then through itself, then attached to the lifting device. 
  • BASKET HITCH (90°): Method of rigging a web sling where the web sling is passed around the load, and both ends are attached to the lifting device. A method of rigging a sling where it’s passed around the load, then through one loop eye, end fitting, or other device, while the other loop eye or end fitting at the other end is attached to the lifting device. Any hitch less than 5 degrees from the vertical may be considered a vertical hitch. 

The degree of the angle determines the rated capacity of the sling—To find out if a sling has the rated capacity you need for a lift, take the angle between the sling leg and the horizontal, then multiply the sling’s factor. 

As the sling angle decreases, so does the rated capacity. Here’s a chart for example:

SLING ANGLE DEGREES  LOSS FACTOR
90 1
85 0.996
80 0.985
75 0.966
70 0.94
65 0.906
60 0.866
55 0.819
50 0.766
45 0.707
40 0.643
35 0.574
30 0.5

 

RIGGING AND LIFTING SLINGS: OTHER FACTORS THAT REDUCE CAPACITY

It’s important to remember that rated capacities are based on perfect conditions. There are many other factors that reduce capacity. These include:

  • Swing: Suspended loads can swing, which place more dynamic forces on the hoist in addition to the weight of the load. These additional forces (see point below) are difficult to quantify and account for, and could cause tip-over of the crane or failure of hoisting hardware. The force of the swinging causes the load to drift away from the machine, which increases the radius and side-loading on equipment. Keep the load directly below the boom point or upper load block. This is best accomplished by controlling the load’s movement with slow motions. 
  • Condition of equipment: Again, WLL and rated capacities are based on perfect conditions – this includes equipment and hardware. Damaged equipment should be taken out of service immediately. 
  • Dynamic forces: WLL and rated capacities are meant for static loads. Safety factor accounts for the dynamic motions of the load & equipment. 
  • Weight of tackle: Hoisting equipment’s rated capacity doesn’t account for the additional weight of blocks, hooks, slings, equalizer beams and other parts of the lifting tackle. The weight of these accessories combined must be added to the load’s total weight, the capacity of the lifting equipment including design safety factors and should be large enough to account for the extra load to lift. 

RIGGING AND LIFTING SLINGS | TERMINOLOGY 

Read on to discover MORE rigging and lifting sling vocabulary you need to know.

ABNORMAL OPERATING CONDITIONS: Environmental conditions that unfavourable, harmful or detrimental to/or for the operation of a sling, such as excessively high or low ambient temperatures, exposure to weather, corrosive fumes, dust or moisture-laden atmospheres and hazardous locations. 

ABRASION: The mechanical wearing of a surface that results from friction with other materials or objects. 

ANGLE OF CHOKE: Angle that’s formed with in a sling body as it passes through the choking-eye or fittings.

ASSEMBLY: Another word for sling.

AUTHORIZED: Approved by a duly-constituted administrative or regulatory authority.  

BODY (SLING): The part of a sling between the eye(s), end-fittings or loop eyes. 

BRIDLE SLING: A sling composed of multiple legs with the top ends gathered in a fitting that goes over the lifting hook. 

D/d RATIO: The relationship between the curvative upon which the sling is used (D) and the nominal sling diameter (d).

DESIGNATED PERSON: Selected or assigned by the employer or employer’s representative as being competent to perform specific duties.

END-FITTING: Terminal hardware on the end of a sling. See sling

EYE OPENING: The opening in the end of a sling of the attachment of the hook, shackle, or other lifting device or the load itself.

FABRICATION EFFICIENCY: The sling assembly strength, as a percentage of the material strength prior to fabrication.

FITTING: Hardware on the end of a sling, also known as a component

GROMMET SLING: A type of endless sling. 

LENGTH, SLING: The distance between the extreme bearing points of the sling.

SINGLE-LEG SLINGS WITHOUT END FITTINGS: Measured from pull to pull with or from bearing to bearing of eyes.

SINGLE-LEG SLINGS WITH END FITTINGS: Measured from pull to pull of end fittings or eyes. 

LOOP EYE (WEB SLING): A length of webbing that has been that’s been folded back upon itself, forming an opening, and joined to the sling body to form a bearing surface. 

PLY: A Layer of load bearing webbing used in a web sling assembly. 

PROOF LOAD: The specific load applied in performance of the proof tests. 

PROOF TEST:A nondestructive load test made to a specific multiple of the rated load of the sling. 

SPECIAL OR INFREQUENT: Service that involves operation other than normal or severe, which is approved by a qualified person. 

SPIRAL: A single transverse coil that is the basic element from which metal mesh is fabricated.

SPLICE (WEB SLING): The part of the sling that’s lapped and secured to become an integral part of the sling.

ASSEMBLY SPLICE (WEB SLING): Any splice that joins two or more parts of the sling without bearing any of the applied load.

LOAD BEARING SPLICE (WEB SLING): The part of a sling that is lapped and secured to become an integral load bearing part of the sling. 

TRIANGLE CHOKER FITTING: An end-fitting for metal mesh or synthetic web slings; similar to the triangle fitting, except that is also a transverse slot through which a triangle fitting can be passed to facilitate a choker hitch on the load.

TRIANGLE FITTING: An end fitting for metal mesh or synthetic web slings, containing a single eye opening for connecting the sling to the lifting device. 

YARN: A generic term for a continuous strand of fibers. 

WE HOPE THIS HELPS—WHETHER YOU WORK OFFSHORE, IN ENTERTAINMENT OR CONSTRUCTION, THIS HANDY GUIDE TO RIGGING AND LIFTING SLINGS TERMS WILL HELP YOU TALK SLINGING SLANG WITH EASE.

HERCULES SLR RIGS IT RIGHT

NEED A LIFT? HERCULES SLR PROVIDES EQUIPMENT, INSPECTIONS & REPAIRS FOR ALL YOUR RIGGING NEEDS—WE LIFT ANYTHING

INFO@HERCULESSLR.COM  1-877-461-4877


FOR RELATED ARTICLES ON RIGGING AND LIFTING SLINGS,

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POLY-WHAT?! ALL ABOUT SYNTHETIC SLINGS

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Hercules SLR is part of the Hercules Group of Companies. We have a unique portfolio of businesses nationally, with locations coast-to-coast. Hercules Group of Companies provides extensive coverage of products and services that support a variety of sectors across Canada which includes the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, mining and marine industries. 

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any hoisting solution your business or project will need. Call us today for more information. 1-877-461-4876 or email info@herculesslr.com

Webbing Sling Q&A: Heavy-Duty Strength for Delicate Lifts

webbing sling from hercules slr

WEBBING SLING: EVERYTHING YOU NEED TO KNOW

If you’re a rigger or work in material handling, you likely encounter webbing slings often in your work. A synthetic webbing sling is fantastic to lift delicate or soft materials, since their soft surface offers more protection than abrasive materials, like wire rope. 

Webbing slings come in two types — duplex and simplex. A duplex webbing sling is made with two synthetic fabric layers stitched together for extra reinforcement. A simplex webbing sling is made with only one synthetic fabric layer.

“Just one layer? That won’t do anything,” you might be thinking—but how wrong you’d be! Even though a webbing sling may not have the same reputation for strength as say, steel, a webbing sling is surprisingly strong. 

There are some misconceptions and often-asked questions about synthetic materials in the industry—so we’ve asked Hercules SLR experts from our Brampton, Ontario branch to help. 

Read on to find out the questions we hear about webbing slings, and how our experts’ answer. 

Q: What are they usually made from? 

Answer: A flat webbing sling is usually made from woven polyester, nylon (otherwise known as polyamide) and polypropylene.   

Q: Do flat webbing slings come in just one width? 

Answer Flat webbing slings come in different widths – but their ultimate flexibility and strength is noted by the number of webbing layers stitched together. 

webbing sling at hercules slr

Q: Should I use paint or dye to colour code webbing slings? This should help me identify them quickly and easily, right?

AnswerNO! Don’t use paint to colour code webbing slings—the solvents in the paint could corrode the synthetic material. A torn or broken sling is unsafe, and will drastically reduce it’s SWL. To identify a synthetic sling’s material, look for the label colour: 

Polyester (PES)—Blue Label, or blue with a green line down the center of the webbing. 

Polyamide (PA)—Green label

Polypropylene (PP)—Brown label

Q: What chemicals will affect webbing slings?

Answer: Polyester isn’t affected much by acid, but alkali’s will damage a polyester webbing sling. An alkali, or alkaline is basically a substance with a pH level higher than 7. Examples of alkali substances are sea water, baking soda, bleaches, lye and even blood. Polyamide’s are basically immune to alkali damage, but are damaged by even moderately-strength acids. They can also lose up to 15% of their SWL when wet. Polypropylene is resistant to acids and alkali’s, which makes them a good choice when you have to lift something which needs protection from chemicals. Be sure the polypropylene is stabilized to protect from ultraviolet degrading. 

Q: What markings should I look for on a webbing sling?

Answer: Look for the safe-working load (SWL), identification number and the label’s colour code.

 Q: How do I store my webbing sling?

AnswerIt definitely matters! Be sure to store your slings in a dry, cool place. Keep them out of sunlight or other ultra-violet radiation, and don’t store them in damp conditions. 

Q: So, they’re really strong – does that mean I can use them to lift anything? 

AnswerDon’t use a webbing sling for a critical lift! Make sure you use extra caution and have a detailed lifting plan for using a webbing sling with delicate or fragile lifting operations. 

Q: Okay, so what’s a critical lift?!

Answer: A critical lift is defined by WorkSafe BC as a lift with high risk factors that could cause the crane or hoist to fail, or poses a significant potential harm to human life. A critical lift is also one that needs a detailed rigging plan before the operation. 

Other factors that can make a lift critical are: 

  • When a piece of powered lifting equipment exceeds it’s rated capacity by 75%;
  • A mobile crane or boom truck goes over rated capacity by 90% lifting a load over 50% of its maximum permitted load radius; 
  • Tandem lifts— which is when more than one piece of powered lifting equipment is used, or is used to lift another piece of lifting equipment);
  • A person is being lifted;
  • The load is under-water or submerged. 

Q: Can I tie a knot in a webbing sling to make it shorter?

Answer: Never! Don’t knot, tie or twist a webbing sling. Don’t manipulate the sling’s angle, either—use the sling however the angle forms naturally.  

hercules slr webbing sling formation types
Figure 1—Webbing Sling Types

Q: When should I not use a webbing sling? 

Answer: Don’t use a webbing sling if you don’t know the SWL. Don’t use if the eyes or other part of the webbing sling is damaged, if the sling’s eye opens more than 20°. There are 5 different types of possible webbing sling eye formations—see figure 1. If using a Type 1 webbing sling (called a choker sling), be sure to protect the eye before use. 

Q: What should I keep in mind when using a webbing sling? 

Answer: There are a few things to consider to use a webbing sling safely—you should always: 

  • Avoid shock-loading;
  • Protect the sling with sleeves when sharp edges could tear its fabric—friction can cause heat damage, which is the most common form of ‘heat’ damage to webbing slings. To prevent, don’t let the sling run along the load’s surface and that it’s not pulled on any sharp corners. This is also known as ‘point loading’, when the load is pulled on a sharp corner, creating heat which results in heat fusion in the sling material. 
  • Never pull a sling from underneath a load.

DOWNLOAD OUR SYNTHETIC SLING INSPECTION GUIDE

References: https://en.oxforddictionaries.com/definition/alkali, https://www.worksafebc.com/en/law-policy/occupational-health-safety/searchable-ohs-regulation/ohs-regulation/part-14-cranes-and-hoists 

Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on FacebookTwitter and LinkedIn for more news and upcoming events.

Poly-What?! All About Synthetic Slings

what-are-synthetic-slings

Synthetic slings are generally available in two varieties – flat-woven web slings and round slings. Textile slings should perform in accordance with ASME standards B30.9-5.

Synthetic Slings: flat-woven web sling (or webbing sling)

Synthetic flat-woven web slings are usually made with woven polyester, polyamide (which is a fancy word for nylon) or polypropylene, and have an eye (basically, a loop) stitched at each end. They are available in Simplex (one layer) or Duplex (two layers).

Web slings are made with a safety factor of at least 5:1 – although other industries may require a higher safety factor.

Synthetic Slings: round slings

Round slings (also known as ’roundslings’) are made from load-bearing fibres with a protective, abrasion-resistant outer later. Their round form is known as ‘endless construction’, and are available in different lengths and capacities.

Synthetic Slings: beat the heat

Consider the temperature of both your surroundings and the load you will lift – synthetic materials have selective resistance to heat, which will effect which sling you choose.

Synthetic sling heat ranges are:

  • Polyester and polyamide: -40°C to 100°C
  • Polypropylene: -40°C to 80°C

These synthetic materials protect against a variety of chemicals, however – they offer different levels of protection against chemicals like acids. Synthetic sling chemical resistance is:

  • Polyamide (Nylon): Resistant to the effects of alkalis, but is attacked by acids.
  • Polyester: Resistant to acids, but damaged by alkalis.
  • Polypropylene: Shows little affect from acids or alkalis. Sustains damage from solvents and paint.
Synthetic Slings: colour codes

Synthetic material in slings are colour coded, in order to identify them properly. The label will be a specific colour, and may also have the type of material written as an abbreviation.

The colour codes are:

what-are-synthetic-slings-
Figure 1: Synthetic Sling Labels

 

Synthetic Slings: eye formations
what-are-synthetic-slings
Figure 2: web sling types

The loop at the end of the web sling is called an eye formation – there are various formations to suit different applications.

There are six different types of web sling types – see figure 2. The six names for these slings are:

  • Type 1—Choker
  • Type 2—Basket
  • Type 3—Eye & Eye
  • Type 4—Twisted Eye
  • Type 5—Endless
  • Type 6—Reversed Eye
Synthetic Sling: round slings

These are made with multiple, high-tenacity yarns, which are covered with a protective sleeve. These are usually made from polyester – but, polyamide (nylon) and polypropylene are available too.

To identify these slings, an identification label is sewn into the cover which details user information and traceability requirements.

They are flexible, light-weight and very flexible.

Synthetic Sling: pre-use inspection

Follow these steps before using your synthetic sling each time – this will ensure you and coworkers will stay safe, and eliminates potential of the sling breaking and damaging the load.

If you find damage on your synthetic sling, it should be removed from service immediately – refer it to a competent person to have it inspected and repaired if necessary.

During your pre-use check, you should:

  • Check the sling label is present and legible and includes manufacturer, rated load for at least one hitch, material type, number of legs (if more than one) and the manufacturers code/stock number.
  • Check that the sling body has no signs of tears, cuts or severe abrasion
  • Check formed eyes for damaged stitching
  • Verify end fittings (where present) function correctly and are undamaged.
  • Check for signs of chemical damage.
  • Check that sling has undergone its periodic thorough inspection.
  • No knots in sling.
Synthetic Slings: shackles, hooks n’ hardware

When you attach a sling to hooks or shackles, take care to ensure the slings don’t bunch around the accessory. Bunching can cause damage since only a portion of the webbing supports the load.

When securing a load with webbing slings, don’t be concerned with the d/d ratio (diameter around the bent sling divided by the body diameter of the sling) – but you must consider the width of the webbing. Follow the manufacturer’s recommendations when you lift with synthetic web slings.

what-are-synthetic-slings
Note: the sling that lies in the shackle fits perfectly – there’s no bunching or a sling that protrudes from the shackle pin.

Hercules SLR – Custom Rigging and Lifting Solutions

Hercules SLR offers custom lifting solutions. We’ll match you with the best equipment and hardware for your project needs, and we’ll customize equipment to meet your specifications.

Need a lift? Drop us a line at info@herculesslr.com to speak with one of our rigging experts – we’ll take you where you need to be.

Need proof? Read about the Frankensling we made for The Town of Oakville Marina, our rigging fundamentals course that Hercules staff from across Canada completed at the Hercules Training Academykeep your synthetic round slings in good working order with our Free Downloadable Synthetic Round Sling Inspection Guide or read our blog on how to prevent synthetic round sling damage.


Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on Twitter, LinkedIn and Facebook for more news and upcoming events.

Behind-the-Scenes: Life of a Slingmaster Sling

slingmaster-sling-hercules-slr-rigging

slingmaster-slingA SlingMaster sling lives a short,  but full life. We’ve covered the less-talked about non-destructive testing here  and here – but what exactly does destructive testing look like, and why do we use it?

Destructive testing is the process used to test a product and find its ultimate load (the load at which the item being tested fails or no longer supports the load) – in this case, a SlingMaster webbing sling’s breaking or tensile strength. This helps our riggers’ determine how our slings perform under different conditions.

First, one of our industrial seamstresses measures and cuts the length of the sling.

Then, the sling travels to our warehouse for destructive testing. The buttons are pressed, and the stretch begins.

The sling is pulled from each end with increasing force applied in increments – this mimics the sensation of a sling supporting a load.

Watch the video below to see the life-cycle of a SlingMaster sling – from birth, to death-by-destructive testing:

Did you know Hercules SLR offers custom rigging solutions? If you have something you want to lift, lower, hoist or move – give us a call. We’ll take you there.

Speak with one of our experts and let us find you the best sling for you or your company’s needs – e-mail us at info@herculsslr.com or call us at 1 (877) 461-4876 for more information.


Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on FacebookTwitter and LinkedIn for more news and upcoming events.