*** DAV Report on Rope Life & Discussion *** Sat Dec 24 17:04:22 1994 Message : #20148515 From: Michael Brodesky Address : brodesky@td2cad.intel.com Group : Usenet.rec.climbing Length : 2943 words Subject : Dav Report on rope age Org. : Alpine Poster With permission from Elmar. DISCLAIMER: This is a partial translation of the DAV rope test report posted on the net (#10358). The original report may vary both in context and results. My translation is in spirit and not literal. There is no guarantee that the translation is accurate or complete. In no way is any deviation from rope manufacturer and UIAA rope use and care guidelines suggested or implied. The translater finds some of the tests and results rather unscientific in their design/interpretation. You are responsible for the use and care of your rope. Section 5: Rope Aging Test 25 sets of twin ropes (2 half ropes per set) were tested. These ropes were given to testers with the condition that they keep a rope journal. From this (journal) the climbing meters and rappelling meters were analyzed. Ropes from the following manufacturers were tested: Beal, Edelrid, Elite, Mammut, Roca, and Salewa (Rivory). After different usage (time, terrain), the ropes were fall tested according to UIAA, DIN, EN standards and the number of held falls was determined. The ropes were tested with falls over edges with radii ranging from 1mm to 5mm (std.). Previously new ropes of the same model were tested over the same edges. The decrease in edge resistance is apparent in the diagram below. Because most of the ropes were used to climb and rappel, the term "usemeters" was coined for the x-axis. "USEMETERS" = climbing meters and rappel meters for a rope team of two (e.g. climbing 400m and rappeling 250m for a rope team of two = 650m) As is seen in the diagram below, there are also ropes with only climbing meters (2)and only rappelling meters (4). edge resistance (%) ^ 100 I I A I a I I BC 50 A a C C I C C c I C C B C CC C I c1CC Cc I C I_____________________________________________________________________________ 0 5000 10000 15000 20000 25000 U S E M E T E R S A=rappel only B=climbing only C=climbing and rappelling 1=rope group C (only use in sandstone(Elbsandstein)) Lower case letter - percentage is lower than ????????? (need more info).... (additionally the original shows an interpolated curve according to 1/x+c, c ~=10). The diagram shows two distinct deviations (high and low values). The high values (little decrease in edge resistance) represent ropes used primarily in slabby limestone (w. few edges). The low values (much decrease in edge resistance) represent ropes mostly used in the Western Alps (granite?) and mixed climbing. 10000 usemeters = 15xFleischbankostwand, 14x rappel through Matejakkamin. A study of single ropes is in preparation. Similar results are expected with increased decrements in edge resistance per use meter. The effect of sand on rope aging hasn't been studied yet, but a strong aging effect is suspected. Astudy will be conducted and results should be available in two years. Translators note: the graph has probably been distorted quite a bit by now. I assume that % edge resistance is the ratio of used falls held/unused falls (x100) held for two different ropes of the same brand/model. Unfortunately the graph doesn't distinguish between falls over edges with different radii (as does the text). Are these 5mm radius falls, pooled (diff. radii) falls ????????? Extra huge grain of salt is applicable. E.Stefke Another Part of the reporT Rope Choices: a.) Sport climbing and toproping: a single rope which can't be used for other climbing (especially alpine) where a fall over an edge could occur b.) Alpine Climbing to Grade III: a single rope, preferably a multi-fall rated rope with enhanced edge resistance c.) Alpine climbing from Grade IV: twin ropes because of the better possibilities for rappel and the redundancy factor when falling (Caution: there is not enough of a safety factor for a rope team of three - two seconds with one rope each) d.) Walking on glaciers: a single rope or (because of weight considerations) a half rope (because of crevasse rescue options this rope should be at least 50m long); use a half rope on the glacier as a single rope and use double ropes (twin) when on the rocks (alpine). e.) Ice climbing: twin ropes because of the better possibilities for rappel and the redundancy factor when falling (Caution: there is not enough of a safety factor for a rope team of three - two seconds with one rope each) Section 1: General Ropes today cannot break anymore at the tie-in point, at the clip in point (pro), and at the belay, regardless of belay method. This is true for ropes which have maintained mantle integrity (not too worn). This is true for "practical" falls, NOT DIN or UIAA standard falls. Practical falls are different from standard falls: 1.) humans do not represent 80kg test weights (up to 30% force reduction when substituting a human for the iron weight) 2.) all belay methods are dynamic and thus reduce force substantially 3.) most practical falls are less than a fall factor of 1 4.) most pro (especially old) would not hold a fall factor of 1.75 (in my opinion the implication is bolts and fixed gear, but this is not addressed adequately in the text) A test conducted on a 14 year old rope showed that it still held a standard fall (this is not true for a fall over an edge). Section 2: Sport Climbing Falls The fall factor in sport climbing situations is usually 0.3-0.5. A sport climbing fall test was devised: 1.) 80kg test (dead-not a climber) weight 2.) no dynamic belay (in order to consistantly test the rope at the same point. 3.) fall factor of 0.34-0.43 (fall height 3-4m) 4.) a standard rope was used Results: 1.) the rope held 220 falls, the mantle broke after the 219th fall. 2.) after 80 falls the rope was flat like a band (webbing?) and blackened severely at the clip-in point 3.) the rope does get damaged in the sense that elasticity and energy dissipation are reduced. 4.) such ropes are dangerous when used in situations where falls over an edge could occur Section 3: toproping falls With impact from toproping falls, a rope cannot break. One can use it until the mantle starts to disintegrate. However, each toprope fall damages the rope similar to a sport climbing fall, only to a lesser extent. With lowering after toproping the rope is additionally damaged. In tests conducted by a reknown rope manufacturer the rope damage experienced after toproping was up to tenfold worse than the rope damage experienced after normal (?) leading and seconding. A frequently used toproping rope may not be used for climbing where falls over an edge may occur. Section 4: Facts Actually everybody knows to get rid of a rope after a big fall. But what is a big fall. Current insights say that it is a fall with a fall factor of 1 or more. Sofar there hasn't been a broken rope from toproping. The same can be said for sport climbing. Since the end of the 60's, ropes have only been broken because of falls over an edge. In each case, cutting of the rope was found to be the cause. In the German speaking region (Austria, Germany, Switzerland), one to two of these situations occured until the mid-80's, generally with deadly outcome, since single ropes were used. The resistance to rope breakage has increased 250% since the late 60"s. Since the mid-80's rope breakage due to falls over an edge suddenly stopped. This could possibly be due to the use of twin ropes in alpine terrain. The edge resistance of twin ropes (ability to absorb fall energy over an edge) is much higher than that of the best single rope. A single rope has 50% more edge resistance than a half rope. There was another broken rope: the rope was exposed to battery fluid and broke on rappel (not at the figure-8 or the rappel anchor, but in the middle of the rope. Back to a fall factor of 1. A rope with such a fall or higher should be removed from climbing (leading), but can still be used for climbing situations which require no edge resistance (falls over edges are not encountered, e.g. sport climbs, toproping). These falls (sport, toprope) can still be held by such a rope (with fall factor of 1) as long as the mantle is not damaged. Section 5: Rope Aging Test 25 sets of twin ropes (2 half ropes per set) were tested. These ropes were given to testers with the condition that they keep a rope journal. From this (journal) the climbing meters and rappelling meters were analyzed. Ropes from the following manufacturers were tested: Beal, Edelrid, Elite, Mammut, Roca, and Salewa (Rivory). After different usage (time, terrain), the ropes were fall tested according to UIAA, DIN, EN standards and the number of held falls was determined. The ropes were tested with falls over edges with radii ranging from 1mm to 5mm (std.). Previously new ropes of the same model were tested over the same edges. The decrease in edge resistance is apparent in the diagram below. Because most of the ropes were used to climb and rappel, the term "usemeters" was coined for the x-axis. "USEMETERS" = climbing meters and rappel meters for a rope team of two (e.g. climbing 400m and rappeling 250m for a rope team of two = 650m) As is seen in the diagram below, there are also ropes with only climbing meters (2)and only rappelling meters (4). edge resistance (%) ^ 100 I I A I a I I BC 50 A a C C I C C c I C C B C CC C I c1CC Cc I C I_____________________________________________________________________________ 0 5000 10000 15000 20000 25000 U S E M E T E R S A=rappel only B=climbing only C=climbing and rappelling 1=rope group C (only use in sandstone(Elbsandstein)) Lower case letter - percentage is lower than percentage one gets when reading across (i.e. reading the Y-axis). (additionally the original shows an interpolated curve according to 1/x+c, c ~=10). The diagram shows two distinct deviations (high and low values). The high values (little decrease in edge resistance) represent ropes used primarily in slabby limestone (w. few edges). The low values (much decrease in edge resistance) represent ropes mostly used in the Western Alps (granite?) and mixed climbing. 10000 usemeters = 15xFleischbankostwand, 14x rappel through Matejakkamin. A study of single ropes is in preparation. Similar results are expected with increased decrements in edge resistance per use meter. The effect of sand on rope aging hasn't been studied yet, but a strong aging effect is suspected. Astudy will be conducted and results should be available in two years. Translators note: the graph has probably been distorted quite a bit by now. I assume that % edge resistance is the ratio of used falls held/unused falls (x100) held for two different ropes of the same brand/model. Unfortunately the graph doesn't distinguish between falls over edges with different radii (as does the text). Are these 5mm radius falls, pooled (diff. radii) falls ????????? Section 6: Rope Choices: a.) Sport climbing and toproping: a single rope which can't be used for other climbing (especially alpine) where a fall over an edge could occur b.) Alpine Climbing to Grade III: a single rope, preferably a multi-fall rated rope with enhanced edge resistance c.) Alpine climbing from Grade IV: twin ropes because of the better possibilities for rappel and the redundancy factor when falling (Caution: there is not enough of a safety factor for a rope team of three - two seconds with one rope each) d.) Walking on glaciers: a single rope or (because of weight considerations) a half rope (because of crevasse rescue options this rope should be at least 50m long); use a half rope on the glacier as a single rope and use double ropes (twin) when on the rocks (alpine). e.) Ice climbing: twin ropes because of the better possibilities for rappel and the redundancy factor when falling (Caution: there is not enough of a safety factor for a rope team of three - two seconds with one rope each) Section 7: Rope Damage Because Of Carabiners Or Wrong Placement: The surface of carabiners may be damaged in a fall at the point at which the carabiner contacts the bolt hanger. Sharp edges on the bolt hanger produce nicks and notches, which could damage the rope in subsequent falls. This could result in ripped mantles and damaged cores. Tests (at a testing facility) using such damaged carabiners have produced no broken rope sofar. To date no known rope failure has occured in real climbing situations (due to carabiners damaged in the described way). Ripped mantles and damaged cores do occur. Rope damage is also possible due to wrong carabiner placement. If the carbiner lies on the rock with its "broad" side, the rope could be pinched. In Buoux (France) a single rope tore to 3 (of 11) strands with a small fall of a few meters. NOTE: The DAV is the German Alpine Club, an organization which frequently conducts tests on climbing equipment. NOTE: There is a brief section which was not translated. It deals with falls on artificial walls and indicates that falls over concrete edges or other edges (fiberglass ????) in rock gyms or other artificial climbing environments could be potentailly dangerous (i.e. ropes can break [be cut]). DISCLAIMER: I've never seen the original DAV report. This is a translation of the post with the DAV (German) heading. The original test results may vary from the post and/or not be accurate. My translation my not be accurate and is definitely in the spirit rather than literal. In my opinion some of the tests were not performed in a very scientific manner and the results are questionable. In no way is any deviation from rope manufacturer or UIAA rope usage and care recommendations suggested or implied. You are responsible for the use and care of your rope. Section 4: Facts Actually everybody knows to get rid of a rope after a big fall. But what is a big fall. Current insights say that it is a fall with a fall factor of 1 or more. Sofar there hasn't been a broken rope from toproping. The same can be said for sport climbing. Since the end of the 60's, ropes have only been broken because of falls over an edge. In each case, cutting of the rope was found to be the cause. In the German speaking region (Austria, Germany, Switzerland), one to two of these situations occured until the mid-80's, generally with deadly outcome, since single ropes were used. The resistanc to rope breakage has increased 250% since the late 60"s. Since the mid-80's rope breakage due to falls over an edge suddenly stopped. This could possibly be due to the use of twin ropes in alpine terrain. The edge resistance of twin ropes (ability to absorb fall energy over an edge) is much higher than that of the best single rope. A single rope has 50% more edge resistance than a half rope. There was another broken rope: the rope was exposed to battery fluid and broke on rappel (not at the figure-8 or the rappel anchor, but in the middle of the rope. Back to a fall factor of 1. A rope with such a fall or higher should be removed from climbing (leading), but can still be used for climbing situations which require no edge resistance (falls over edges are not encountered, e.g. sport climbs, toproping). These falls (sport, toprope) can still be held by such a rope (with fall factor of 1) as long as the mantle is not damaged. More to follow. Take the extra huge grain of salt. E.Stefke My views are my own. Michael Brodesky Internet Mbrodesky@sc9.Intel.com Send Email for the List of climbing gyms, in the US, Asia, or Europe UUCP : {pur-ee,qanad,oliveb,decwrl,hplabs}!intelca!mipos3!td2cad!brodesky Looking for the famous #12 hex. BD hammer for cheap. C4 body suit for OW. (Michael Brodesky) Subject: Rope Life Date: Sat, 18 Jan 1997 21:50:22 -0800 From: Bill Ellison To: sar-l@islandnet.com I thought there would be more discussion on the question of determining when to retire rescue ropes. I assume that most teams are keeping rope logs these days, but what exactly are they doing with them? Back in the '70's, "Off Belay" (a magazine now out of print) did an article on a study done by the German Alpine Club. This study found that once a rope was basically taken out the bag, the tensile strength of the rope dropped to about 50% of new in about six years. In addition, (if my memory serves me correctly) it didn't appear to matter how much the rope was used! Now this study was using dynamic rope but I still find the study rather sobering if true. (This study seems to conflict with other studies done subsequently that have had various results.) Steve Hudson shared what I believe is the current standard used by a lot of teams (a decrease of about 2% tensile strength per year). This too raises some questions, however. NFPA recommends a 15:1 safety margin for lifelines. If fire departments are using 12.5mm rope with a tensile strength of 9000lbs., ('15' times a rescue load of 600lbs. equals 9,000 lbs), after one year (theoretically) the rope should be retired. Is anyone doing that? So here's my question(s): What safety factor/margin are teams using to design their systems, and how are they tested? If your team/agency is using a safety factor of less than 10:1 (the standard in industry), how will you defend that in court? And last but not least, what criteria are teams really using to determine when to retire those expensive ropes? Bill Ellison "If the situation is hopeless, why worry?" Subject: Rope Life Date: Sun, 19 Jan 1997 05:38:21 -0800 (PST) From: Harry Patz To: sar-l@islandnet.com On Sat, 18 Jan 1997, Bill Ellison wrote: > NFPA recommends a 15:1 safety margin for > lifelines. If fire departments are using 12.5mm rope with a tensile > strength of 9000lbs., ('15' times a rescue load of 600lbs. equals 9,000 > lbs), after one year (theoretically) the rope should be retired. Is > anyone doing that? ===================================================================== NFPA got around this issue by requiring a 'new' rope for every actual rescue. Common sense prevailed as the capital budget said we cannot afford to replace ropes at that rate. They are working on more changes to the guidelines (by the way, they are only guidelines) to a more practical recommendations. > So here's my question(s): What safety factor/margin are teams using to > design their systems, and how are they tested? If your team/agency is > using a safety factor of less than 10:1 (the standard in industry), how > will you defend that in court? And last but not least, what criteria are > teams really using to determine when to retire those expensive ropes? Bill: These are great questions and I have often discussed and raised the same. As a general rule I teach and practice a 10:1 safety factor. The reasons are mostly common sense. For instance, any knot tied in a rope will weaken it. Exactly how much is not important here. The point is it is now less than that optimum of 15:1. There are many examples of strength reduction from the maximum in practice today. So........... 10:1 appears to be both realistic and practical. In addition, NFPA are 'guidelines only' as I said compared to OSHA supported statements which are traced to testing through ASTM or ANSI and actually have data to support their safety factor. The industrial shock abosorber is a classic example. Rope Retirement: Bellingham Mtn. Rescue cycles every three years unless special exposure dictates otherwise. In the industrial schools I teach, we go through ropes approximately every six months. Most of this is based on the environment. Frequent exposure to industrial facilities increases the degradation potential and ropes are too cheap as opposed to guessing and risking a failure. Defending Your Position in Court: This is a tough one. My two cents says the answer will follow what happens in EMS. Determining what was "prudent." In that case, one will be in for quite the spectrum as this country is hardly together on rescue practices. In my opinion, the fire service will likely be the basis whether you like it or not. Look around for 'standards' in the rescue industry. Where are they? Wherever you see the most is likely where the comparison will be made. My opinions only. Harry Patz -------------------------------------------