Ziplining can be a fun activity catered to people of different experience levels. You can do a moderately short, slow zip line if you’re not chasing after thrills or you can zipline 60 or more feet off the ground. No matter your ziplining height or speed, you wonder whether the line is likely to break. Has it ever happened?
Yes, zip lines can break, but it’s usually not without warning. The line is comprised of galvanized wire ropes that are layered together. As many as seven cables may be attached to make one zip line, and each of those cables has smaller cables. Before they snap, the smaller cables wear down. Ziplining staff members will see the signs of wear and tear and replace the line before your ride.
In this article, we’ll talk more about what a zip line is made of. Then we’ll delve into the safety of ziplining with statistics, including how likely the line is to break when you’re riding. If you’re thinking of going zip lining but you’re on the fence, this is one article you won’t want to miss!
What Are Zip Lines Made of?
The zip line itself is one part of many that make up the zip line system. The other parts of that system include the trolley, which is where you sit, and two platforms. You use one platform as a launching pad for your zipline ride, then the second platform is where you land when you make it down to the bottom. Brakes are included as well.
Some zip line systems have one cable and others two. Reputable ziplining companies will only use zip line cables made of galvanized wire rope. The rope includes cables woven together, then those cables have even slimmer layers of woven cables. It becomes like a Russian nesting doll situation but in the best, safest way possible.
Here is an example of what a strand of galvanized wire rope that’s used for zip lining looks like. You can see that each cable includes much smaller cables, which altogether create a very sturdy ziplining rope.
Galvanized wire rope is said to be stronger than a rope of the same size made of stainless steel. Another perk is that the galvanized wire rope won’t corrode thanks to an outer rustproof layer. Zipline rope comes in different thicknesses depending on how tight the cable is. A tighter cable requires a bigger rope diameter. By shrinking the diameter, the zip line rope is looser and typically takes on a U-shape.
The size of the zip line also influences how smooth your ride is as well as how long it will last. The smoothest galvanized wire rope is typically the largest, and that’s true of long cables as well.
Do Zip Lines Ever Snap?
By now, a lot of people have heard the story of Aimee Copeland, a young woman from Georgia who, in 2012, had a zip-lining accident that led to her being infected by a flesh-eating bacteria that nearly took her life. Her line snapped, but there’s a lot more to that story that tends to get overshadowed by the flesh-eating bacteria part (which is fair!).
The zip line Copeland used wasn’t professional-grade. It was something she found by a riverside. As the People article we linked in the paragraph above states, the zip line was “not much more than a dog wire with handlebars.” It’s no wonder it snapped upon use. In this case, the results were almost deadly, but fortunately, Copeland is alive and healthy today (although she did have several limbs amputated as a result of the bacteria).
That story, as sad as it is, has no bearing on the safety of commercial ziplining with guides, as they use professional-grade equipment. Still, can that high-quality zip line ever snap? Well, we’d never say never, but it’s incredibly unlikely for a variety of reasons.
Ziplining Weight Limits
First, commercial zip lining companies employ weight limits that must be followed when allowing any riders to zip line. If you’ve read about hot air ballooning and parasailing on this blog, it’s the same case for both of these sky-bound activities as well.
The weight limit doesn’t exist to offend, but to ensure your safety. In the case of ziplining, the weight limit is typically around 250 pounds. If you weigh more than that, you shouldn’t go ziplining, as your safety can be at risk.
Galvanized Line Quality
Besides the weight limit, there’s also the quality of the line used. Galvanized 7×19 wire strand rope includes a wire strand core or fiber core for greater durability. This type of zip line is also known to have among the best breaking load.
The breaking load of galvanized wire rope is per 1,770 megapascals (Mpa), a pressure unit. The load is then expressed in kilograms or kilonewtons, with 1 kilonewton equal to 224.81 pounds.
Using 7×19 galvanized steel wire as an example, if the nominal diameter was 3 millimeters and the approximate mass was 0.034 kilograms per meter (kg/m), then the minimum breaking load per 1,770 Mpa would be 5.77 kilonewtons. That means the minimum breaking load of galvanized wire rope at that limit would be 1,297.1 pounds.
Let’s say the nominal diameter is 20 millimeters and the approximate mass is 1.524 kg/m. Now the minimum breaking load per 1,770 Mpa is 256.30 kilonewtons. Going back to what we said before, that 1 kilonewton = 224.81 pounds, if we multiply 224.81 by 256.30, we get a minimum breaking load of 57,618.8 pounds.
If you’re still not convinced, How Stuff Works talked to the Professional Ropes Course Association or PRCA’s president of its board of directors, Steve Gustafson, about the safety of zip lining. He mentions that the smallest cables of the galvanized wire rope tend to show their wear and tear first. That makes them the most important part of the zip line itself.
Every day, ahead of admitting riders for ziplining, the crew at the zip line company are instructed to check the lines for signs of wear. Before the line snaps, the crew would see that the filaments are frayed and then replace the line with fresher, stronger wire rope.
By the way, the PRCA is one of many organizations like it that oversee commercial ziplining companies. Another is the Association for Challenge Course Technology or AACT. Both organizations require that zip line operators receive professional-level accreditation. On top of that, in Europe, ziplining organizations are certified by the European Ropes Course Association, and in the United States, it’s the American National Standards Institute or ANSI. In other words, you can’t become a zipline operator without strict standards in place.
Here’s what all the info in this section tells us. While a zip line certainly can snap, by using the industry standard of galvanized wire rope and checking it every day as well as by following the recommended ziplining weight limit, there’s no reason to stress about the line snapping. The filaments in the smaller cables of the wire rope would have to have been seriously neglected to fall into such a state of disarray that the line would suddenly snap.
Is Ziplining Safe?
It’s good to know the zip line itself isn’t likely to break, but that doesn’t mean other things can’t go wrong during your ride. You could trip and fall off the platform, straining the line. Maybe your brakes malfunction and you slam into a platform or a tree on the other side of the zip line. How likely are these incidents to occur?
It’s not easy to answer that question, as there isn’t a database that collects data on ziplining injuries and deaths. What we have to go on are bits and pieces of info that, when put together, can better indicate the safety of ziplining.
One such piece of info is from Robson Forensic, which cites an American Journal of Emergency Medicine study from 2015. According to the data in that study, as of 2012, the United States had had 3,600 zip line injuries. It’s unclear what year the data comparisons started, but the journal mentions that this rate of injuries means that 11.64 people out of a million will be hurt when ziplining.
The rate of amusement park injuries, according to the same study, is 0.0127 in a million, which would make ziplining less safe than going to a theme park. Continuing with the results of the study, most injuries from ziplining are broken bones, up to 46 percent. Another 15.2 percent of those injured sustain bruises, then 15.1 percent suffer sprains and strains. Only seven percent have a closed head injury such as a concussion.
Robson Forensic mentions a piece of data from Ohio State University that found that 12 percent of all people injured in a ziplining accident need to go to a hospital. Another stat from that article is that from 2006 to 2016, 16 people died zip lining in the US. This was mostly from falling from heights, with up to 77 percent of the deaths attributed to that.
This 2016 article in Claims Journal also sheds some light on ziplining safety. Their report mentions that in 2001, the US had only 10 ziplining injuries, but by 2012, it had risen to 200 that year. This data is provided courtesy of the Center for Injury Research and Policy through The Research Institute at Nationwide Children’s Hospital. Claims Journal adds that between 1997 and 2002, the US reported 16,850 ziplining injuries, all non-fatal.
Ziplining accidents do seem to be on the rise, as do injuries. Keep in mind the above stats do not account for amateur ziplining, but only commercial operations. That said, we do want to remind you that the crew who administers your ziplining experience are accredited professionals. On top of that, many zip lining companies have not just one brake system installed, but backup brakes in case the first set of brakes fails.
No activity in which you’re high in the sky will ever be 100 percent safe, but ziplining is not as dangerous as some people make it out to be.
Ziplines themselves are made of multi-layered galvanized wire rope with smaller filaments that fray first before the line would ever break. With daily inspections required of the ziplining crew, they’d notice the filaments giving way and replace the zip line before any riders use it. We hope the information in this article puts your mind at ease so you can focus more on enjoying your ziplining ride than the rope breaking!