RESCUE ROPE: LIFELINE VS. THE BOTTOM LINE
BY CHUCK DEAN
Many fire departments throughout the country are involved in high-angle rescue and are actively using modern static rescue ropes in these operations. NFPA 1983, Fire Service Life Safety Rope and System Components, 1995 revision, is very specific about the tensile strength, size requirements, and technical construction of the ropes to ensure that any ropes used for rescue within the fire service are suitable for the task. When originally proposed, NFPA 1983 stated that only new rope should be used for rescue and that once used it should be destroyed. Obviously, that part of the standard was to ensure that the rope used for an actual rescue would meet the established criteria–and only the status of rope that was never used could be considered the most reliable. The objective of the standard was ideal–to ensure that the most reliable rope was available for the most dangerous of tasks.
Unfortunately, we did not at the time the standard was enacted and still do not operate in a perfect world. It seems that budgetary constraints often overrule the ideal, and rescue ropes have been used beyond the recommended one time use. After inspection, the ropes were put back in service or relegated to “training” purposes, even though they still were used to support life loads in this mode. This reality has resulted in a revision of the standard, which now includes criteria for reusing rope.
The questions many rescuers have asked over time are, Just how reliable are used ropes in this scenario? Based on experience, just how much degradation will a rope sustain with use? The unknowns in all rope operations make it impossible to tell how many rappels or litter lowers a rope can take before it should be retired, even with judiciously kept rope logs.
TESTS OF USED RESCUE ROPES
These “unknowns” prompted a fire department to recently conduct a test of old rescue ropes in an attempt to quantify rope degradation and the resulting safety factor.
The test, conducted by a university-level mechanical engineering department, consisted of the destructive testing of various pieces of retired rescue ropes using a Baldwin Universal test machine to determine the actual breaking point. The machine, used by research labs to determine the strength of materials, uses a 124,000-pound hydraulic ram to measure the tensile strength within plus or minus one pound of accuracy. Note: Interpretation of the results is not based on formal statistical analysis techniques but is more of an informal (“backyard”) view.
The test segments, all one-half-inch static kernmantle of various brands, were cut from the middle of the ropes. Unbeknownst to the testers, duplicate segments from the same ropes were identified as segments from different ropes. After initial attachment problems that shredded the first specimen, the ropes were alternately fastened to the test rig by tying bights on each end with figure-8 knots. These bights were then placed over hooks, allowing the machine to gradually pull the ropes apart. The results of the empirical data then were compared with the information recorded on the rope logs. The raw data from the test are shown below:
ROPE # BREAKING STRENGTH (POUNDS)
* The attempt to clamp the rope to the test system resulted in the rope`s shredding. This figure was not used in any average calculations. A different attachment was used for all other test attempts.
The average breaking strength of the tested specimens was 5,287 pounds. Although dealing with averages is not necessarily the best approach when dealing with life-saving situations, it is helpful in risk-management decisions. It indicates that the tested ropes (including the rope that failed at only 4,990 pounds) are well within the NFPA standard for a one-person load rope using a 15-to-1 safety factor (300-pound load ¥ 15 = 4,500 pounds).
LOG BOOK DATA
Analysis of the rope log books indicated heavy usage of the ropes in an actual mountain-rescue environment. Even training evolutions were done in the actual mountain area with weather and terrain typical of actual rescue situations, as opposed to using a cleaner concrete training site. The results of averaging the log book entries are indicated below:
High-angle litter lowers 9
Lowering rope for one-on-one
(one-person load lowered
by mechanical brake) 12
Self-rescue (prusik) 5
(low-angle evacuation) 4
Tyrolean traverse (main line) 1
Anchor system 1
Actual rescues 1
Note: These are the results of the entries made while the rope was in service for a full year. Additional training usage for practice setup at ground level of rescue systems, the extent unknown, was placed on these ropes while they were stored in stations. The ropes ranged in age from two to seven years.
Regardless of the fact that “backyard” test techniques lack sufficient controls or true statistical techniques, they are valid in assisting personnel with decisions and often will verify or refute assumptions gained through experience in the school of hard knocks. Based on this particular test, one can assume that the ropes taken out of service were still capable of being used as one-person-load ropes. After the considerable use they had undergone, the ropes had almost the same strength as new 716-inch mountain lay nylon rope, used in high-angle mountain rescue prior to the introduction of static kernmantle. That fact alone has provided many less-experienced personnel with greater confidence when using less-than-brand-new rope on training and rescue evolutions. This type of information, combined with experience and the rope manufacturers` recommended inspection procedures, also may be useful to personnel trying to evaluate when to remove ropes from service.
The current NFPA Standard 1983 is an excellent guide for replacing rescue rope within the fire service. Unfortunately, the reality of the bottom line in many fire department budgets requires answers to risk-management decisions that are not available in absolute form. Someone must put his or someone else`s life on the line. When to retire rope is one of those decisions. In rope rescue, as with other aspects of the fire service, there are no guarantees even when all the rules are followed. It is a calculated risk at best, with the odds hopefully stacked in your favor.
Use the information derived from this test with caution. File it away with other experience for the future. Combined with the rope manufacturer`s guidelines for inspecting, it may be of value at some time in the future when you find yourself facing the decision of whether to retire a rope or reuse it. Obviously, when in doubt, the best course of action is to replace the rope. As is the case with firefighting, experience and technical competency still are the most valid tools for making decisions concerning high-angle rescue operations. They may be required when the bottom line is in conflict with rescue lines. n
n CHUCK DEAN is a captain with the Colorado Springs (CO) Fire Department and was instrumental in establishing the department?s high-angle rescue program. He serves as the program coordinator and company officer of one of its high-angle rescue units (the department averages more than 30 high-angle rescues a year). Dean has almost 25 years of technical rope rescue and mountaineering experience that includes serving as leader of the U.S. Army High Altitude Mountain Rescue Team, instructor training officer of the Army?s ski-mountaineering school in Alaska, and a nationally appointed mountaineering instructor within the National Ski Patrol System. He has had numerous articles on rope rescue techniques published in fire service-related magazines.