Working Load Limit, Breaking Strength & Safety Factor: What Do They Mean?

Ever saw random numbers on your load-bearing equipment and didn’t know what they mean? Read to learn what working load limit, break strength, and safety factor mean.

Have you picked up a ratchet strap and saw numbers labeled on the strap, and wonder what they mean? Chances are you’re reading the working load limit or break strength. Every piece of load-bearing equipment states these requirements to let you know how much weight that piece of rigging is capable of securing.

When it comes to securing fragile or heavy loads, it is crucial that the product can secure the load without breaking. Although these terms are normally stated, there is confusion about what these terms mean. Read on below to learn what working load limit, break strength, and safety factor mean.

What Does Working Load Limit Mean?

shackle displaying the wll
Displaying a Shackle with the Working Load Limit

Many people ask about the working load limit, and this is a term to not mix up with breaking strength. Abbreviated as WLL, it is the rating that should never be exceeded when using a product like a ratchet strap. Before using a piece of load-bearing equipment, always make sure to look at the working load limit before use as it is the maximum allowable loading force.

Something to keep in mind is the working load limit is always 1/3 of the breaking strength. So if a ratchet strap has a breaking strength of 15,000 pounds, then the strap will have a working load limit of 5,000 pounds.

To learn how to secure your cargo, read how to use tie downs to secure cargo loads safely and legally.

If the Working Load Limit is Included, is the Break Strength Important?

breaking strength meaning displayed on our tag
Displaying a custom strap with the Break Strength and Working Load Limit

The break strength is equally as important as the working load limit. The break strength refers to the point at which your load-bearing equipment will fail. It is expressed in pounds and/or kilograms, and will actually fail if you go over the required amount.

When a ratchet strap is made with webbing, end fittings, and a ratchet all with a 10,000-pound breaking strength, then the break strength of the overall product will stay 10,000 pounds. However, if the same strap has a ratchet with an 8,000-pound break strength, then that would reduce the product’s strength to 8,000.

What is the Correlation with Safety Factor?

factor of safety, what is factor of safety?
Multiple tie downs securing cargo loads

Safety factor, also known as Design Factor, determines the ratio between the working load limit and break strength. The working load limit’s rating should never exceed when using a sling or tiedown, and this safety factor provides an allowance for shock loading, G force, and other unforeseen factors.

How Do I Know my Load-Bearing Equipment is Failing?

To make sure your lifting equipment is performing its best, perform an inspection. If you see any damage to the product, dispose of it. To give you an insight into what kind of damage you can potentially see, read these examples:

  • Holes, tears, cuts, snags, or embedded particles
  • Broken or worn stitching
  • Abrasive wear
  • Bending
  • Melting, charring, or weld spatter
  • Acid or alkali burns
  • Any other visible damage which causes doubt to the strength of the equipment

When selecting a ratchet strap, lifting sling, shackle, or any other product, select the product that has suitable characteristics for the type of load, environment, and attachment to the vehicle.

At US Cargo Control, we want you to be safe when securing heavy loads. If you have any questions about the safety requirements, give our team a call at 800-404-7068.

4 Tips for Buying the Right Rigging & Lifting Equipment

If you work in the rigging and lifting industry you know that, when lives are on the line, close is never close enough. Safety measures, procedures, and equipment specs have to be spot-on.

Maintaining a safe job site starts with having the proper equipment for the job. But, with thousands of different rigging products, each with their own distinct characteristics, capabilities, and reputation, many riggers face the struggle of trying to choose the correct rigging and lifting equipment for the job.

Here are the 4 main things to pay attention to when deciding which rigging and lifting products are best for your particular job.

 

1. Assess what your lifting

To start, you need to assess the object or objects you are needing to lift or rig up. Does the object have sharp corners? Where is the center of gravity in your load? How much lifting space do you have? Asking these questions first will help to narrow down the potential rigging gear you can safely and effectively use for the job.

 

 

2. Know your Load Limit

working load limit on lifting gear for safety

Working load limit is the maximum weight that can safely be applied to a given piece of rigging equipment. It’s different for each individual piece of equipment, so be sure to pay close attention to this when selecting your rigging and lifting gear. Just one weak area puts the entire operation at risk. Check the weight of your load first, then ensure that you only buy equipment that is rated for that weight or more.

 

 

3. Consider Temperature & Environment

tips for choosing best rigging and lifting equipment

In applications that experience extremely high or low temperatures, certain equipment may not operate properly. For example, if you’re working in a high-heat environment, you will want to use wire rope with an independent wire rope core (IWRC) instead of a fiber core (FC). Also, consider the worksite environment. If saltwater is a factor, buy stainless steel rigging gear to prevent corrosion.

 

 

4. Opt for Quality

high quality lifting and rigging gear for manufacturing industry

Strength and durability is the name of the game when it comes to rigging and lifting gear. For the best chance of avoiding accidents and equipment that wears out quickly, you’ll want to ensure that you’re purchasing high-quality rigging equipment from trustworthy sources. It may not always be the most affordable choice, but it will be the smartest choice in the long run.

 

The importance of buying the right equipment is clear when you consider the stakes of lifting and handling heavy loads. Don’t guess. Take the time to thoroughly evaluate the job at hand before buying. When you do buy rigging and lifting supplies, be sure to check all the manufacturer specifications and ask questions if you’re unsure.

USCC has a team of dedicated product consultants that are just a phone call away. If you have product questions or would like to place an order over the phone instead of on our website, give them a call at 800-404-7068.

 

Using Tie Downs to Secure Cargo Loads Safely and Legally

During the 2017 CVSA International Roadcheck, improper cargo securement was the cause for 15.7% of vehicles being placed out of service.

Besides the risk of being placed out of service, there are a number of more serious consequences for improper cargo control securement, including citations and fines, damage to the vehicle, damage to the cargo, loss of the load, or even loss of life.

Taking the time to properly secure cargo loads using tie downs is always worth the time and effort. Read on to understand how tie downs should be used to ensure safe and legal cargo securement.

 

understand how to use tie downs

What is a tie down?

According to the Federal Motor Carrier Safety Administration (FMCSA), a tie down is a combination of securing devices (webbing, chain, rope, binders, shackles, D-rings, webbing ratchet, etc.) which forms an assembly that:

  1. Attaches cargo to, or restrains cargo on a vehicle.
  2. Is attached to an anchor point(s).

 

So, while we generally think of tie downs as just these:

how to safely use tie down straps

 

 

 

 

 

 

 

 

 

The word tie down by itself (without “straps”) can technically mean many things.

 

Working load limit for tie downs

The working load limit (WLL) for a tie down is the lowest WLL of any of its parts or the WLL of the anchor points it is attached to, whichever is less. Every device contributes to the WLL of the securement system.

using tie downs

 

 

 

 

 

 

 

 

 

Always use tie downs that are rated and clearly marked by their manufacturer. This not only gives you, the driver, peace of mind, it also makes it easy for shippers and inspectors to verify that you are using the proper equipment for the job.

 

using tie downs built with quality

 

How tie downs can be used to secure cargo

Tie downs are only safe and effective if they are properly secured to both the cargo and the vehicle. Take the time to ensure logical securement of your cargo to your vehicle.

There are two main ways tie downs can be used:

  1. Attached to the cargo.
    a. Tie downs can be attached to the vehicle and then attached to the cargo.
    b. Or, tie downs can be attached to the vehicle, passed through or around the cargo, and then attached to the vehicle again.

how to use tie downs

 

 

 

 

 

 

 

 

 

  1. Passed over the cargo.
    a. Tie downs may also be attached to the vehicle, passed over the cargo, and then attached to the vehicle again.

how to use tie downs

 

 

 

 

 

 

 

Inspecting for proper cargo securement

Remember to periodically inspect your cargo during transit. It may seem like something that is always taking up your precious time, but just one loose strap can prove to be costly or even deadly.

Adjust cargo and load securement devices as necessary to ensure that cargo cannot shift or fall from the vehicle.

 

When is it time to get new tie-downs?

There are a few obvious signs that tell you it’s time to get new tie downs.

If your cargo control equipment shows any of the following, it’s time to invest in new tie downs.

  • knots or obvious damage
  • distress
  • weakened parts
  • weakened sections

time to get new tie downs

 

 

 

Remember, all components of a tie down must be in proper working order. Keep an eye on the condition of your tie downs to avoid inspection penalties or loss of load.

 

Time for new tie down equipment? Check out US Cargo Control for a huge selection of quality tie down equipment that is clearly rated and built to last.

 

Aggregate Working Load Limits

OLYMPUS DIGITAL CAMERAWith such a wide range of strength and length in commercial tie downs, it’s important to determine the aggregate working load limit of the equipment you choose before you attempt to haul your cargo.

What does aggregate working load limit mean?

Working load limits determine how much weight or force tiedowns and other securing devices can secure without breaking. The aggregate working load limit is the sum of the working load limits for each device you use to secure your load. To meet safety requirements, the aggregate working load limit of the devices you use must be at least 50% of the total weight of all the pieces of cargo you are hauling.

shutterstock_1131225How do you determine aggregate working load limits?

You can figure out the aggregate working load limit of your securing devices by adding together:

  • 50% of the working load limit of each tiedown that is attached to an anchor point on your vehicle, and
  • 50% of the working load limit of each tiedown that is attached to your vehicle and goes over, around or through your cargo.

The sum equals your aggregate working load limit. It’s important to properly figure your aggregate working load limit and use the necessary amount of tiedowns for every load you haul. If you don’t, you risk being cited by the DOT or losing your cargo on the road, which could lead to serious injury to you or to another motorist.

New Products: BlackLine Ratchet Straps, Winch Straps and Roll Off Straps

Our new BlackLine tie down straps were developed for US Cargo Control so we could offer customers premium tie downs with the strongest webbing on the market.

The line includes 2” and 4” wide ratchet straps, winch straps and roll off straps with higher break strengths than traditional webbing, to create an increased working load limit (WLL). 2″ straps have 13,000 lb. webbing while 4″ straps feature 24,000lbs webbing. This  means 4″ ratchet straps have a WLL of 6,670 lbs., while competitor’s straps have a 5,400 lbs. WLL.

Because BlackLine products are manufactured specifically for US Cargo Control, we were able to add additional features like thicker edges for increased durability. This design is made possible with a concentration of tough webbing, not an enhancement like thin wire.

We’ve also added black powder coating on flat hooks and 2” wide ratchet assemblies both protection and sleek style. Wire hooks and chain extensions also have zinc plating for increased resistance against the elements. The black color scheme coordinates better with company logos and colors than traditional colored straps.

As with all of our straps, BlackLine ratchet straps, winch straps and roll off container straps are labeled with WLL information so they meet DOT regulations, CVSA guidelines, CHP, North American Cargo Securement, and WSTDA standards.

Read the official press release about our new BlackLine tie down straps.

 

Tie Down Strap Tag Information: Break Strength and Working Load Limit

Webbing tie down straps like ratchet straps and cam buckle straps should be marked with a tag indicating the break strength and working load limit. Blackline tie down straps from USCargoControl.com

 What does the break strength mean on tie downs?

According to the Web Sling and Tie Down Association (WSTDA), breaking strength is the load in pounds or kilograms at which point any load bearing part of the synthetic web tie down fails.

 What does working load limit mean?

The working load limit, also marked at WLL, is the maximum allowable load assigned to each synthetic web tie down by the manufacturer which is not to exceed one-third of the complete assembly breaking strength. This means a strap with a break strength of 16,200 lbs. would have a WLL of 5,400 lbs.