….The author`s belief that the “90 degrees or less anchoring rule” may not be used due to the urgency of the rescue is wrong. The laws of physics do not know or care if you are a recreational mountain climber or a firefighter attempting a rescue. If the angle exceeds 90 degrees, the anchor must be deemed unsafe, and another anchoring system must be established. An example of an unsafe anchor is being presented as a tensionless anchor (photo, p. 43). Due to an incorrect number of spirals, the running end of the rope has tension on it, creating a sharp angle where the carabiner attaches to the standing end.
….The author considers a “Class II” harness as within his minimum safety parameters, mentioning NFPA 1983 in regard to rope (but not harnesses); yet NFPA 1983 only recognizes the “Class III” harness for inversion. Inverting in a lesser class (I or II) harness will lead to the removal of the harness from the rescuer. The sixth, seventh, and eighth photos of the aerial ladder evolution have an inverted firefighter in a “Class II” harness.
The author states that the figure of eight is the “predominant descending device….” If there is anything “predominant” about the figure of eight, it is that it is a one-person rappel device that twists the rope and does not have the ability to create a wide variety of friction–not the best selection when two-person loads are a possibility.
…In the “out-a-window descent” and “aerial ladder” scenarios, the rescuers are in the process of “getting on the system”; yet in each scenario, the rescuers are doing this with unlocked (not tied off) figure of eights.
The author himself recognizes that “you may get hung up going over the edge and not have the strength or manpower available to get back to the start point.” No matter what type of descender you have, it should be securely tied off before attempting to “get on the system,” for this is a “both-hands-required” stage of the evolution.
In the seventh photo of the “aerial ladder” evolution, an inverted firefighter in a harness not rated for inversion is going over the edge in an unsecured figure of eight, presumably going to rescue a second person using a one-person rappel device (no haul system is mentioned or evident)….
Dave Kaktis
Firefighter
Posen (IL) Fire Department
Kenneth J. Brennan responds: ….Nowhere in the article did I arbitrarily advocate exceeding the 90-degree rule. As a matter of fact, there were four references to the contrary: “Keep the angle small or add additional anchor points.” The bottom line is to keep your angles small, and this can be accomplished by increasing your run-outs when needed.
Regarding the tensionless anchor`s (shown on page 43) being unsafe, let`s review tensionless anchors. Two methods are used to set up this technique. The first rule is, the pipe or tree must be at least eight times the diameter of the rope. This means that to have no strength loss, a 12-inch rope must be wrapped around a four-inch or larger pipe. Wrap it sufficiently for the loads anticipated. I suggested six to 10 wraps, as this accounts for I-beam and square timber that may be used in the field.
The second rule is real simple: Wrap the object enough times so that when you pull on the standing end, the rope doesn`t move. The picture on page 43 shows a correct setup. This 12-inch rope is wrapped four times around a 12-inch pipe, which provides sufficient surface area for a two-man load. There is no sharp angle. As a matter of fact, the slack came off the back, and the running end was “tensionless.”
Mr. Kaktis is right in that NFPA 1983, chapter 4-1.2 (C) mentions [the use of a class III harness] when inverting may occur. The reality is that the vast majority of these evolutions don`t involve inverting, and class II harnesses are the minimum. A properly donned and adjusted class II harness will be difficult to be “removed from,” particularly when wearing bunker pants. The reality is, the truckie or rescueman will be wearing the harness as part of his roof gear, and nobody I know is going to wear a class III harness just in case the need for such an operation arises (the probability is slight).
Regarding the figure of eight, I realize several devices are in use today; I selected the most common one out there. “Predominant” means more than 50 percent or most commonly purchased. A cursory call to suppliers of fire departments revealed that the figure-of-eight device was purchased more often than, say, the rack. For short-distance rappelling, this appears to be predominant. When I asked what the predominantly purchased team device for lowering was, the rack was predominant. As we know, this device provides more friction and flexibility. A cursory check of bunker coat pockets will show more figure of eights than rappel racks….
With regard to the “out-a-window de-scent” and “aerial ladder” scenarios and the rescuer`s “getting on the system” unlocked (not tied off) with regard to the figure-of-eight-device,….the “out-a-window” technique shows the firefighter safe and secure inside the building, and the “aerial ladder” technique shows the firefighter hooking up from a place of safety. “Locking off” wouldn`t be possible and may cause a true rope lock-up situation and that`s why the article was created. Maintaining the standing end taut is paramount to successfully getting over the edge. You obviously must hook up correctly and be secured to the system.
