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Myth Busters

Myth #1: You should replace a dropped carabiner because of undetectable "Micro-Fractures".

This is the biggest myth we know of, and was probably created by unscrupulous salesmen to get you to buy more carabiners.

CarabineerTruth: In a test by Steve Nagode, an engineer at the REI quality
assurance laboratory, 30 carabiner bodies (half ovals, half D’s) were each dropped six times onto a concrete floor from a height of 33 feet.  Following the drops, their open-gate strength was measured and compared to 30 control samples from the same production batch and which had not been dropped.  The statistical result showed "no loss
of strength.”  Inspect any piece of dropped equipment carefully, checking for proper function. Cast metal products are most
vulnerable to damage, fractures and cracks. To my personal knowledge, this happened once to a gray cast metal Jumar ascender in the 1970's. To my extensive knowledge: Drop forged carabiners (and similar gear) have not exhibited this problem.

Note: OEM Petzl says: 1mm of wear or gouge is serious enough wear or damage to require replacement.

 

Myth #2: If a harness has a belay loop for attachment, by-pass the belay loop with a carabiner; connecting the waist belt with the leg loops.

Truth: Harnesses that incorporate a belay loop (8,000-13,000 pound strength) should be used as the manufacturer directs and the belay point should be used as the attachment point.  Read the harness manufacturers directions. Belay_Loop

No one has ever advocated using a "by-pass" carabiner, replacing/supplementing the harness belay loop. This engages the waist belt, engaging all the wearer’s internal organs, as a life support element instead of transferring the force to the legs like the harness’s belay loop is designed to do.

Belay loops are also affixed to the center of the harness to assist in keeping you centered on the rope in normal use or a fall. A "by-pass" carabiner can move to the side under a fall or even normal loading, causing you to dangle from the side, rather than the center.

Even more important, carabiners need to be allowed to orient themselves as they are pulled/used in the direction of the force. If a carabiner is pulled in two directions as it is done in a by-pass carabiner, any third force will be forced to load the gate of the carabiner.  Petzl and others strongly advise against such actions and their recent testing points up that most gates will snap off about at 85 pounds of force.

Warning: Using the 'belt' for life support can damage the spleen, liver, kidneys, pancreas, appendix and breathing capacity. Do not "Aussie" rappel (face down) as it also turns the belt into the sole life support component. If entangled or caught in this position you may have only 1 minute 20 seconds of hanging in freefall in this position before blackout, followed by death.  The exception: highly trained SWAT team members using gear designed for this technique and for very specific reasons.

 

Myth #3: People stranded in sit harness all have similar problems to overcome.

Truth: Not so.  Overweight climbers stranded in a harness may suffocate and die within minutes if not rescued. Sit harnesses squeeze gut mass into the abdominal breathing space and cause the user to suffer advanced suffocation symptoms in a matter of seconds. Stranded climbers need to be brought to firm ground or use an etrier or similar device (prusik loop) to relieve abdominal pressure.

                                     Rope Rescue Training - ExxonMobil
 

Myth #4: A High Strength Tie-off (Frictionless Hitch) needs 3 wraps around the anchor.

Truth: It often only needs two wraps around the anchor. If properly named, it would be called the tension-full hitch instead of the tensionless hitch. Most trees, I-beams and other anchor points provide all the friction necessary to keep the rope tangent to the anchor and provide full rope strength in two wraps. One of the biggest issues is the terrible waste of resources. Resources wasted include: time and rope.

                                                                Incorrect!!!     
                    
                                        Tensionless Hitch

Myth #5: Dressing a knot makes the knot stronger.

Truth: Dressing a knot allows the knot to be easily inspectable, not necessarily stronger. This allows for easy verification that the knot is tied correctly.

For example: A Figure 9 when tied right is both stronger and easier to untie then a figure 8, yet it takes substantially more scrutiny to discern that it is tied correctly. Because of this most rescue teams opt to use a Figure 8 over a Figure 9.


      The Knot                Triple Fishermans

Myth #6: A Figure 8 knot tied "backwards" is 10% weaker.

Truth: Absolutely incorrect. The second a load is applied to the 'outside' loop.  It will be forced to the inside of the course the lines take as they trace the knot. All efforts to keep the load line at a greater radius will only result in the load line taking the path of the lesser radius.

                                    Figure of Eight Loop

Myth #7: Racks should be used with the bars facing the user: i.e. facing the flat side of the rack.

Truth: John Cole, NASA Engineer and inventor of the rack, in an interview at the 2005 NSS Convention, stated that he designed it so the user actually looks at the ends of the brake bars, with the open leg positioned away from the user’s body. This allows for easy adding and subtracting bars as needed by rocking the rope back and forth (left and right) in front of the user. Moving the rope in and out, especially with lots of rope below, is difficult if not impossible.

                                                   SMC_Rack


Myth #8: Cleaning rope with a pressure washer drives the dirt particles deep into the fibers.

Truth: A pressure washer does a terrific job of cleaning rope as thoroughly as we have ever seen. The core remains pure white, if not whiter after such cleaning.

Personal Proof: pressure wash (all or just a tail) a very dirty rope. Cut off approximately 1 foot, strip the kernmantle and examine the core fibers closely.

        Rope_Cleaning         Rope_Cleaning1


Myth #9: Walking on rope damages it.         

Truth: Not unless you are wearing ice crampons or razor blades.  There is even recent discussion that claims crampons in snow just pass through the rope fibers and cause no harm to the rope.

Jim Kovach, in an exhaustive 8 month study in Ohio, and reported to/by ITRS (International Technical Rescue Symposium) including using rope as a doormat for months, and then driving over the same rope while it lay on beds of broken chards of Rope_Washing bricks and a glazer’s pile of broken glass. Then the rope was pull tested! Although the kernmantle showed minor signs of wear, in testing no loss of strength was seen. There is no evidence that stepping on a rope will grind dirt past the kernmantle into the core.

Personal proof: Cut about 1 foot off an old very used rope and examine the core of the rope yourself.

In other testing done by CMC out of California, rope were immersed in various substances for long periods of time and then tested. Some of these included paint, tar, sap, gasoline, oil and vomit. Most of the test items, including gasoline and oil, did not cause strength problems (although an oily rope is tough to use, it did not weaken the rope). Acidic materials, like vomit and animal urine, can cause a 30 percent or more strength reduction.

 


Myth #10: Personal recreation vertical gear / descent devices are suitable for commercial applications such as ropes courses, climbing walls, and industrial applications.

Truth: Personal recreational devices, especially descenders like ATC's, smaller figure 8's, and Pirana's are sized for intermittent personal use. Smaller devices are unable to dissipate the heat, the main by-product, during use in these more demanding applications.
   Figure_8_Device  Black Diamond ATC Pirana


Myth #11: Opposite and Opposing Carabiners used in conjunction establish a more secure connection.
Opp_Opposed_Carabineers

Truth: This only applies to NON-LOCKING carabiners, which should not be used in applications requiring such safety. This should have become a non-issue in WWII when locking carabiners were invented. Instead, carabiner users have hung onto some of these old methods and think they apply to all carabiners.  This is not so.

Proper positioning of two locking carabiners is via similar orientation, i.e.: both gates in same position, and are used for added strength or greater rope radius.

 


Myth #12: While climbing, body belays are preferred.

Truth: This technique goes back to our alpine climbing roots using snow and ice anchors. It is a preferred method on fragile anchors which can be softened by the floppy mass of your climbing partner. Climbing where there are good anchors, granite and deep rooted trees means you should use these items as the anchor of first choice and free yourself to be of aid to your partner if needed.


Body_Belay


Myth # 13:  15 to 1 is the NFPA (National Fire Protection Association) safety standard. 

This is not true.  The problem is the “Which came first analogy?”   Professional rope users, as outlined by the NFPA, are supposed to use ½” ropes which break at approximately 9000 lbs.  And years ago they said that a Fireman’s load would be defined as 600 lbs. (2 person load).  Working backwards with these numbers.  Hummmmmm!  9000 lbs divided by 600 lbs gives us a safety factor of 15 to 1.  But history will tell us the 9000 lbs and the 600 lb numbers came first not the 15 to 1.  It just conveniently worked out that way. The accepted and recognized rope user safety factor is 10 to 1.

NFPA


Myth # 14:  Prusik cord lengths should be standard.

Prusik cord lengths are dependent on many factors.  Spouting specific lengths for optimum performance, i.e. 65” and 54” is inaccurate. Let’s detail what must occur. Prusik cord should be about 70% the diameter of the primary climbing line (i.e. 6 mm Prusik cord  9 mm primary, or 8 mm Prusik cord on 11.1 mm primary, or 9 mm Prusik cord on 12.5 mm primary climbing line). The breaking strength of your Prusik cord should be approximately half the breaking strength of your primary climbing line to optimize the strength of your rigging. There should be a ¾” space between the bottom of a PMP and the end of the Prusik hitch.

                      The Knot        Prusiks


Myth # 15: Rope strength can be determined by looking at the manufacturer’s documents.

NO! Rope strength includes the calculation of 3 factors every time a rope is used.

  • Knots! A knot will reduce the strength of your rigging by approximately 1/3 of the rope‘s strength.The Knot
  • Wet/Dry! Nylon rope will lose 15% of its strength when wet.  Polyester loses no strength when wet.
  • Age!  A rope loses about 2% of its strength per year even when it is kept in a like-new condition , even if it has never been used.

                                 

These three are allotted for when using the 10 to 1 safety margin.  Unless any of the three are excessive, i.e. a 20 year old wet rope with an overhand knot (50-55% efficiency) can push a rope beyond its life support abilities.
( -40% age- 15% wet, -45% knot) = 0 strength.

 

Myth # 16: Belays are required.

Belays are not mandatory.  Double line work adds a huge degree of added safety, but belays can, more often than not, be hazardous. 

In free space the payload can spin and tangle the two lines together into hopeless dysfunction. a rappeller on belay in free space may spin hopelessly in his belay.  Climbing or rappelling a rope rigged side-by-side another can result in the same critical and deadly problem (Ellisons 1999).

Lipke’s Technical Rigger’s Guide discusses that at 40 degrees a main and belay (2 lines) become his recommended option, but under 40 degrees it is optional or negligible.

Belay


Myth # 17: Knots should be backed up.

Back-up knots are often a violation of good efficiency and a waste of time .  There are a limited number of knots that may require back-up.  A professional should know which ones need a back-up and under what circumstances. 

Making a statement like, “All knots should be backed-up” is irresponsible and shows a huge lack of knowledge about something as basic as a knot.  Why would you back-up a knot? You answer, “In case you tied the main knot incorrectly.”

Backing up a knot that is tied wrong screams of incompetence. And when does it end? How do you back up a butterfly knot, a bowline on a bight or a Double fisherman’s knot? The bigger issue is the terrible waste of resources. Resources wasted includes: time, rope, throw, and/or usable operational space.

                                Backup Knot


Myth # 18: Double Loop Knots are stronger.

NO! Double loop knots are not stronger (i.e. Double Figure Eight) Knots, when pull tested, all break where the standing line goes into the knot configuration, not at the loop.  A bigger argument against large Double loop knots is their terrible waste of resources including: convenience, space, rope and throw. Frequently, gate loading becomes a frequent occurrence.  It only takes about 85 lbs to tear a gate off a carabiner. Rope or webbing should never extend beyond 1 inch from the spine.  Even then, it reduces the strength of the carabiner by 1/3.

Double_Fig_8


Myth #19: Gibbs Ascenders are good for commercial and cable applications

NO!  After extensive tests, Gibbs clearly prints on the warning card that comes with each ascender, “GIBBS ASCENDERS #1 and #2 will cut a new ½” inch nylon rope at 2000 lbs.” They go on to say they are, “Not for use on Steel Cable or wire rope.”

                      Gibbs Ascender Sports Model


Myth # 20:  The Rule of 12 applies to both high line tensioning and haul systems.

The rule actually says that no haul system should exceed 12 people hauling or mechanical advantage of 12 to 1 or any combination of the two. i.e. 3 people pulling a 4 to 1…3 X 4 = 12

This applies to a 7/16” (11.1 mm) rope. A ½” rope moves to the Rule of 18. Haulers are only pulling a few feet when tensioning a high line, while a haul system depends on the hauling of long distances and a much larger number of folks can be used so as not to exhaust the haulers.

If the system becomes too difficult to haul, look carefully at all the components of the system. Typically, the system needs only for you to reduce internal friction. 

                                   Highline