As a teenager, I spent many summer days sunbathing in my backyard drenched in baby oil. Today I’m more likely to be slathering on sunscreen and wearing a hat and sunglasses. Our fascination with tanning may have begun with the invention of the bikini in 1946, later instilled in our social conscience by the blond haired Coppertone girl and her cocker spaniel. It’s hard to believe it was as recently as the 1990s when we first started hearing in earnest from dermatologists about how damaging the sun is to our skin. Terms like melanoma, SPF, and ultraviolet (UV) rays are now part of our common vocabulary.
This awareness transcends health and ventures into the world of safety. In 2003 the Web Sling and Tie Down Association (WSTDA) released test results showing UV degradation on synthetic web slings. According to the WSTDA, web slings can lose up to 40 percent of their strength when exposed to the sun for just 16 months. Recommendations for prevention are incorporated into the 2004 document “Recommended Standard Specification for Synthetic Web Slings.” The standard cautions that degradation can take place without visible indications, although some tip-offs include bleaching, stiffness, and abrasion. It identifies factors that affect the degree of loss and suggests ways to reduce the sun’s effect on slings.
In February, the Technical Committee of the Associated Wire Rope Fabricators (AWRF) voted to consider doing similar testing on synthetic round slings. The key difference here is that the core yarns that make up the load-bearing portion of a round sling are protected by an outer cover. Those covers come in a variety of colors and transparencies. The question has been raised whether some covers protect better than others. At press time, the project was in the hands of the Round Sling Subcommittee and the scope and methodology of the testing were not yet determined.
In talking with a number of interested parties, it seems the topic may not be as straightforward as it first appears, but it is sure to be one of much debate in the coming months and years. While I don’t pretend to be an engineer or scientist, it only takes common sense to know that the sun does impact the viability of synthetic slings, just as it does our skin. Which types of fibers and to what degree in a given period are among the questions yet to be answered.
In the meantime, look to existing research to guide your inspections of synthetic slings. Go to the Products/Standards section at www.wstda.com to purchase the UV Degradation Report and the standard mentioned previously. Likewise, ASME B30.9 may be useful as well as information from manufacturers of synthetic slings. Look for additional discussion about this in the Guest Perspectives in May issue of Crane Hot Line on pages 14 and 15.
Just as Australia continues its National Skin Cancer Awareness Campaign to combat the statistic that it has the highest incidence of skin cancer in the world, awareness is also essential to the safety of sling users. Greater study can only lead to a better understanding of the issue as well as improved use and inspection of synthetic slings. I applaud these industry organizations for delving more deeply into these issues.
And since construction workers spend so much of their time outdoors, I also want to mention that this month is National Skin Cancer Awareness Month. It may not have a direct correlation to cranes and rigging, but a reminder to workers to take precautions to protect their skin is a worthy topic for your next safety meeting.