I once told Don Blair I thought I could tell when to retire a line that had always been used in natural crotches by the visible wear, but I asked, “How do you know when to retire a line that has only been used with a block and a lowering device?” Kind of at a loss, he said all he could suggest was to keep a log, the same advice given by the people interviewed for your article, “Ins & Outs, Ups & Downs of Rigging Rope” (TCI Magazine, July 2020). But no one said what this log should look like, and the question remains, even if you have a log of the history of use for a rigging line, when do you retire it?
Kurt Woltersdorf, owner
Don Blair, CTSP, a 38-year TCIA member and president of Blair’s Arborist Equipment, LLC, in Hagerstown, Maryland, responds:
The arborist states that the rigging line has only been used with a block-and-lowering-device system. Running through a block and on a lowering device does help to reduce the sort of abrasion that would be encountered if only doing natural-crotch rigging. However, depending upon how the rope is rigged, there may still be times when the rope runs hard against the trunk or limb on its way down. Therefore, the line should be checked thoroughly and carefully for signs of abrasion. Remember the protocol for inspections: initial, frequent and periodic.
Initial – Upon receipt of new equipment, make sure it is in new, serviceable condition and free of defects. Make sure it is exactly what you ordered.
Frequent – In the yard, if the rigging line is drawn from supply along with the lowering device, and in the field if on the truck, inspect before first use. You do not need a microscope. As you lay out the rope, pay attention to its condition. Learn the feel of burns, hard spots and nicks every time the rope runs through your hands. Check the rope at the end of the day when it is being put away, coiled or flaked into a bag. If it’s wet, dirty or muddy, dry it and/or clean it before the next use.
Periodic – This is a scheduled inspection by a designated employee qualified to examine and inspect. The frequency of use determines the cycle of inspection.
Inspection: If the lowering line is eye-spliced, look carefully at the stitching that runs through the splice. If any of the stitches are broken, that is a good indication the rope was subjected to an impact load that has quite likely compromised the fibers and weakened the line. Withdraw it from service and replace it.
If the lowering line has been used carefully, and continues to pass all stages of inspection, or a damaged or worn section can be removed, making the remaining length of line serviceable, time then becomes the most important factor. I would recommend checking with the manufacturer of the cordage you employ and ask them what they consider the outside service life of the specific product you are using. Considering product liability from the manufacturer’s perspective, you can expect them to take a conservative approach in their answer.
With all of this said, I will continue to say, as I have for more than 50 years, “The best time to replace any piece of equipment is before it breaks!” That advice should ring especially loud when
considering life-support components of your climbing system, all components of any rigging system and anything else that can kill or maim if it fails (and this includes the tree). The more critical the product is to your life and livelihood (as well as the rest of your team), the more you should pay attention to how it’s being used.
Apply this final thought to every aspect of your personal and professional life, and you will be amazed at how many problems you can avoid: “If there’s doubt, there is no doubt!”
Tchukki Andersen, CTSP, BCMA and TCIA staff arborist, also responds:
Retire a rigging rope based on use and visual and tactile clues, including looking for deformities, wear, fraying, etc. And yes, keeping a log will help you keep track of how much weight the rope has seen over time; some manufacturers offer rope logs in their packaging.
Rope-retirement criteria is basically a combination of what the manufacturer would recommend and the number/severity of wear factors.
Talk to the rope manufacturer regarding use. Then handwrite a use log that tracks the amount of weight loaded with an estimate of cycles of use. Say you know you used a specific rope about 15 times for removing about five 180-pound pieces, four 300-pound pieces and three 500-pound pieces. Record that total weight. The manufacturer should have a chart for its rope similar to the one accompanying this response (Figure 1) that you then can use to determine if the rope has reached its capacity over time.
If the rope isn’t showing signs of wear, then use the accompanying cycles-to-failure chart (Figure 2, from TCIA’s Best Practices for Rigging in Arboriculture manual) to determine when to retire it. If you see signs of wear before the cycles to failure have been reached, retire the line. When in doubt, retire the line.