A Detailed Guide to Breaking Strength vs Working Load Limit
Have you ever picked up a strap and wondered about those numbers on it? Those numbers usually tell you the working load limit or breaking strength. Knowing these can really help you figure out how much weight the rigging can handle safely.
But here’s the thing: terms like “Breaking Strength” (BS) and “Working Load Limit” (WLL) often get mixed up, and we get how confusing that can be. Since these terms are crucial for picking the right tow straps, recovery straps, winches, and ratchet straps, we want to break them down as simply as possible.
In this article, we’ll dig into the differences between breaking strength and working load limit. Our goal is to help you pick the right recovery gear and understand the ratings for your equipment. By getting a clear handle on these terms, you can secure fragile or heavy loads without worrying about gear failure. So, read on to learn more about WLL, breaking strength, and safety factors!
What exactly is breaking strength?
Breaking strength (BS) is all about the maximum force a ratchet strap can take before it tears or gets damaged. Think of it as the absolute limit of what each part of the strap setup—whether it’s the webbing, the ratchet, or the end fittings—can handle. Every part gets independently tested to find out its breaking strength.
Now, here’s the kicker: the BS of the whole tie-down setup is only as strong as its weakest link. So, if your webbing can handle 3,500 pounds but your end fittings are only rated for 3,000 pounds, your strap’s breaking strength is 3,000 pounds. And just a heads-up, breaking strength isn’t the same as the weight your strap can safely secure. That’s a different number you’ve got to keep in mind for safe hauling. Let me give you an example—if your strap has a breaking strength (BS) of 3,000 lbs, that doesn’t mean it can safely secure a load of 3,000 lbs.
Note that you should never push a product to its breaking strength. If you use a tow strap or shackle near or at its breaking strength (BS), it’s likely to fail, maybe not right away, but definitely after a few uses. So, if you can’t use a product at its breaking strength, how do you figure out its safe limits? That’s where the working load limit (WLL) comes in.
What about working load limit?
Working load limit (WLL) is basically the safe weight limit for your ratchet straps or any other rigging gear. It’s the maximum weight that the equipment can handle on a regular basis without risking damage or failure.
Think of it as a safety margin that manufacturers build in to make sure you’re not pushing the gear to its breaking point. Take one of the retractable ratchet straps from Strapinno for example, the strap is used for tying down cargo, motorcycle, boat, and kayak, and has a 1800lbs/816kgs breaking strength and 600lbs/272kgs working load limit. It means that you can safely secure up to 600 pounds with it, day in and day out, without worrying about it giving out on you.
It’s important to always pay attention to the WLL when you’re tying down a load because it ensures you’re using the strap within its safe limits. Going beyond this limit can lead to strap failure, which can cause damage or even accidents. So, always check the WLL to keep your load secure and your ride safe.
What is safety factor?
A product’s safety factor (SF) is basically the ratio of its breaking strength to its working load limit (WLL). For instance, if you’ve got a shackle with a safety factor of 6:1, and its breaking strength is 30,000 pounds, then its WLL is 5,000 pounds. Safety factor shows how much stronger the product is compared to what you’ll be using it for. The higher the safety factor, the safer the product.
Now, these safety factors aren’t always regulated. The Cordage Institute, which sets standards for rope use, suggests a safety factor between 5:1 and 12:1. However, most winch lines and straps only have a safety factor of 4:1 or 3:1, and some military gear even goes as low as 2:1!
You can use the safety factor to figure out the WLL from the breaking strength. Just divide the breaking strength (BS) by the safety factor. For example, if a steel cable has a 1,800-pound MBS and a 3:1 SF, divide 1,800 by 3, and you get a 600-pound WLL. Simple as that!
Breaking Strength vs. Working Load Limit
Alright, now that we’ve got a handle on the key values for recovery gear, let’s break it down. Breaking strength is the maximum force a strap can take before it fails. Think of it as the absolute limit. On the other hand, the working load limit (WLL) is the safe weight you can use the strap for day in and day out without any worries.
Always go by the WLL to make sure your cargo is safe and secure during transport. It’s the number you should be focusing on to avoid any mishaps. Now, let’s dive into the main differences between breaking strength and working load limit, and how you should use each one properly.
Breaking Strength
It’s crucial to remember that you should never use a product at or near its breaking strength (BS), except in an absolute emergency when there are no other options. For instance, if your ATV is about to get swept away in a rapidly rising river, then sure, test the limits of your strap—just make sure everyone is safe first.
Also, once you’ve subjected a piece of gear to forces near its breaking strength, even if there aren’t any visible signs of damage, it’s time to retire it. These products are designed to handle their BS only once without failing. Using them again could lead to catastrophic failure.
When you’re picking out recovery gear like tow straps, shackles, and ratchet straps, don’t focus solely on the breaking strength; what really matters is the working load limit, which we’ll cover soon. That said, it’s still smart to choose products with a breaking strength well above the forces they’ll face. For example, if you’ve got a 700-pound ATV, go for gear with a breaking strength in the thousands—around 3,000 pounds—considering the safety factor and working load limit. This way, you’re playing it safe and making sure your gear won’t let you down.
Working Load Limit
Always keep an eye on the WLL when you’re tying down a load—it’s your guarantee that you’re using the strap within its safe limits. When you’re choosing lifting or rigging gear, you’ve got to determine the right working load limit (WLL) based on what you’re lifting or pulling and how much weight or force will be involved. The WLL should be equal to or greater than the load you’re working with. If you push beyond this limit, you risk strap failure, which can lead to damage or even accidents.
You also need to think about factors like the angle of the load, how many attachment points you’re using, and the condition of the equipment. These things can all affect how much weight the gear can safely handle.
Usually, tie-down straps have their working load limit (WLL) and breaking strength listed right on the label. But if that info isn’t there, you can easily calculate it yourself. It’s pretty straightforward! To figure out the WLL, you need to know the breaking strength and the safety factor. Just divide the breaking strength by the safety factor. For instance, if the breaking strength is 10,000 pounds and the safety factor is 5:1, then the WLL would be 2,000 pounds.
How do I know my strap is failing?
To make sure your lifting equipment is in top shape, you need to inspect it regularly. If you spot any damage, get rid of the equipment. Here are some examples of what to look for:
- 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 that raises doubts about the equipment’s strength
When you’re picking out a ratchet strap, lifting sling, shackle, or any other product, make sure it’s suitable for the type of load, the environment, and how it attaches to your vehicle.
Read more: How to Maintain Retractable Ratchet Straps?
Importance of Proper Labeling
To make things easy, all of Strapinno’s ratchet straps come with labels. These labels tell you the strap’s breaking strength and working load limit, so you don’t have to do any math.
Just check the labels to ensure you’re using the right strap for your needs and following the recommended load limits. This clear labeling system helps keep everything safe and compliant during transportation.
Why Retractable Ratchet Straps?
Retractable ratchet straps, or retractable tie-downs, are a real game-changer for keeping your stuff safe during transport. Unlike regular ratchet straps, these guys automatically retract, so setting them up and using them takes less than a minute. Plus, you won’t have any excess straps flapping around while you’re driving. We all know how annoying that can be.
Choosing the Right Retractable Tie-Downs
When picking retractable ratchet straps, it’s crucial to match the breaking strength and working load limit with the weight and type of your cargo. Make sure you choose straps that meet or exceed your needs for safety and reliability during transport.
Also, consider factors like weather conditions, how the load is distributed, and where the straps attach to your vehicle. These can all impact the performance of your straps.
Read more: Retractable Ratchet Straps vs. Traditional Ratchet Straps
Safety Precautions and Proper Usage
To get the most out of your tie-downs and ensure safe transportation, follow these quick tips:
- Regularly check the straps for wear and tear, like fraying, cuts, or damaged hardware.
- Make sure the strap is positioned correctly, with no twists or knots that could weaken it.
- Apply tension evenly across the webbing to distribute the load properly.
- Ensure the ratchet mechanism is fully engaged and locked to prevent slipping.
- Use edge protectors when securing loads with sharp or rough edges to protect the strap and your vehicle.
What are the requirements for the straps?
Tie-down straps need to meet specific performance standards set by the Federal Motor Carrier Safety Administration (FMCSA). The Web Sling and Tie Down Association (WSTDA) also lays out standards and guidelines to ensure web slings and tie-downs are safe and high-quality.
At Strapinno, we make sure our tie-down straps meet these standards by following the WSTDA guidelines. These guidelines cover everything from design and testing to proper labeling, ensuring our straps are top-notch and reliable for your needs.
Final thoughts
Remember, the working load limits are what really matter when you’re picking out a strap. Strapinno’s got you covered with all kinds of retractable ratchet straps that have the right working load limits and breaking strength. So, let’s find the strap that fits your needs. But most importantly, stay safe out there, and enjoy your travels knowing your gear is locked down with the strength and reliability of retractable tie-downs!
FAQs
1. What is the difference between breaking strength and working load limit?
Breaking strength is the maximum force a strap or piece of equipment can handle before it fails. Working load limit (WLL) is the maximum force that the equipment can safely handle during regular use.
2. What is the ratio of the breaking strength to the working load limit?
The ratio we’re talking about is known as the safety factor, and it can vary depending on the equipment. Typically, it’s about 3:1 or 4:1, meaning the breaking strength is three or four times the working load limit. Just a side note—3:1 is a common ratio you’ll see with ratchet straps when comparing their BS to their WLL.
3. What is the difference between WLL and MRC?
The difference between WLL (Working Load Limit) and MRC (Maximum Rated Capacity) comes down to how they’re used and the safety margins involved:
- WLL (Working Load Limit): This is the maximum load a piece of gear, like a ratchet strap or shackle, can safely handle during regular use. It’s a conservative number that includes a safety margin to prevent any failures during normal operations.
- MRC (Maximum Rated Capacity): This is the absolute max load the equipment is rated to handle under specific, often controlled, conditions. It’s the upper limit of what the gear can handle, but it doesn’t have the same built-in safety margin as the WLL.
In simple terms, WLL is what you should follow for everyday use to keep things safe. MRC, on the other hand, is the maximum capacity the equipment can technically handle, but it’s not something you want to rely on for regular use.
4. What is the working load limit of a sling that has a breaking strength of 10,000 pounds?
If the safety factor is 5:1, the working load limit would be 2,000 pounds (10,000 ÷ 5).
5. What is the difference between load capacity and working load limit?
Load capacity is the general term for the maximum weight equipment can handle. Working load limit is a more specific term referring to the maximum weight the equipment can safely handle during normal use.
6. How do you calculate working load limit?
You calculate the WLL by dividing the breaking strength by the safety factor. For example, if the breaking strength is 10,000 pounds and the safety factor is 5:1, the WLL is 2,000 pounds.
7. What is the difference between SWL and WLL?
SWL (Safe Working Load) and WLL (Working Load Limit) essentially mean the same thing—they both refer to the maximum safe load the equipment can handle during regular use.
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Learn more about Strapinno’s patent ratchet strap safety technology here.
