|
|
|
|
tradrenn
Feb 16, 2008, 7:25 AM
Post #26 of 72
(1101 views)
Shortcut
Registered: Jan 16, 2005
Posts: 2990
|
majid_sabet wrote: A single rope that is rated to 5000 lbs is insufficient for rescue work cause ,as soon as you put the knot in there, you will loose 30% which brings the value to @2800 lbs or safety factor 6:1. This is why two rope are used in rescue to increase the safety factor to at least 12:1. How did you get 2800 lbs ? 30 % of 5000 is 1500 Shouldn't you end it up with 3500 ?
majid_sabet wrote: In climbing, there are no such standard or at least no one builds an anchor or uses a biner with such safety factors in mind. Yes there are. They are called 2 to 1 Let me give you an example: Cranes are build to that standard, when a company that makes cranes wants to built one that is suppose to be rated for 40 tons they have to test it by hanging 80 tons for half an hour, static load FYI. Cranes are regulated by laws, whether climbing gear is or not I honestly don't know. Majid: Are you expecting climbing (or other staff ) gear to be rated to its absolute maximum strength ? Can you imagine just for a second what would happen to my crane once I loaded with 40.25 tons ? Same goes for climbing equipment, basically it is stronger then necessary for a reason, you never know or pulley effect is that reason.
majid_sabet wrote: Most people feel that two cams in the crack and leaving one draw on TR does the job and there they go off the wall. Where in the word did you get that info ?
majid_sabet wrote: I am confident that most manufacturer know why they build their gear in such ways, I'm confident too.
majid_sabet wrote: but does public has any idea why these ratings are for ?. No they don't. You should understand that we are living in a society that is define by one statement: "The law is here to protect MORONS from themselfs"
majid_sabet wrote: Do we feel safer with a gear rated 5 times more than what we could generate during a fall ? I can't answer for everyone else that climbs, but I can tell you that, YES I feel safer. V.
|
|
|
|
|
dobson
Feb 16, 2008, 8:04 AM
Post #27 of 72
(1093 views)
Shortcut
Registered: Oct 6, 2004
Posts: 104
|
In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. Pounds force (lbf) are an imperial unit of force, independent of gravity. One kn is ~225 lbf.
|
|
|
|
|
jt512
Feb 16, 2008, 8:14 AM
Post #28 of 72
(1089 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
dobson wrote: In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. These threads are so predictable. F = ma. Let a = g. Then F = mg = w. Thus weight is a force. Jay
|
|
|
|
|
hugepedro
Feb 16, 2008, 9:51 AM
Post #29 of 72
(1083 views)
Shortcut
Registered: May 28, 2002
Posts: 2875
|
majid_sabet wrote: In climbing, there are no such standard or at least no one builds an anchor or uses a biner with such safety factors in mind. I beg to differ. There absolutely is a safety standard in climbing. Gear is designed around the principle that a lead fall should never generate more than 12kn on the falling climber. No, it is not like a 15:1 standard. You, the climber, are responsible for deciding how much overkill you want and are comfortable with, and that is how it should be.
majid_sabet wrote: Most people feel that two cams in the crack and leaving one draw on TR does the job and there they go off the wall. Really? "Most people"???? I've never seen anyone TR off of 1 draw, or 2 pieces of pro, let alone most people.
majid_sabet wrote: Do we feel safer with a gear rated 5 times more than what we could generate during a fall ? You have climbing gear rated to 80kn? I don't have any on my rack. Please tell me what gear you have that is rated to 80kn.
|
|
|
|
|
majid_sabet
Feb 16, 2008, 10:33 AM
Post #30 of 72
(1079 views)
Shortcut
Registered: Dec 13, 2002
Posts: 8390
|
hugepedro wrote: majid_sabet wrote: In climbing, there are no such standard or at least no one builds an anchor or uses a biner with such safety factors in mind. I beg to differ. There absolutely is a safety standard in climbing. Gear is designed around the principle that a lead fall should never generate more than 12kn on the falling climber. No, it is not like a 15:1 standard. You, the climber, are responsible for deciding how much overkill you want and are comfortable with, and that is how it should be. majid_sabet wrote: Most people feel that two cams in the crack and leaving one draw on TR does the job and there they go off the wall. Really? "Most people"???? I've never seen anyone TR off of 1 draw, or 2 pieces of pro, let alone most people. majid_sabet wrote: Do we feel safer with a gear rated 5 times more than what we could generate during a fall ? You have climbing gear rated to 80kn? I don't have any on my rack. Please tell me what gear you have that is rated to 80kn. Safety standards in climbing ? You mean something that is well documented and has been approved as standard ? Like how to jumar or what belay device you must use or you can not rap with rope under this size etc ?
|
|
|
|
|
corson
Feb 16, 2008, 11:01 AM
Post #31 of 72
(1089 views)
Shortcut
Registered: Oct 16, 2005
Posts: 193
|
jt512 wrote: d1r73 wrote: And yet we still hear of gear failures. I know I have heard of biners snapping on slacklines, harnesses failing, cams breaking, ropes snapping... etc etc I will give you that most of this was probably improper use and/or excessive wear and tear, but mfg know this shit happens and therefore build to account for a certain degree of stupidity/cheapness/laziness/misuses by the users. Also it's nice to have gear that is OBVIOUSLY way too worn to be using before it fails structurally. Harnesses failing? Ropes "snapping?" Where else but rc.com can you get quality misinformation like this! Jay I think pee-wees play house did a segment on snapping ropes.............Maybe that was smokin' ropes. I forget
|
|
|
|
|
corson
Feb 16, 2008, 11:12 AM
Post #32 of 72
(1086 views)
Shortcut
Registered: Oct 16, 2005
Posts: 193
|
majid_sabet wrote: hugepedro wrote: majid_sabet wrote: In climbing, there are no such standard or at least no one builds an anchor or uses a biner with such safety factors in mind. I beg to differ. There absolutely is a safety standard in climbing. Gear is designed around the principle that a lead fall should never generate more than 12kn on the falling climber. No, it is not like a 15:1 standard. You, the climber, are responsible for deciding how much overkill you want and are comfortable with, and that is how it should be. majid_sabet wrote: Most people feel that two cams in the crack and leaving one draw on TR does the job and there they go off the wall. Really? "Most people"???? I've never seen anyone TR off of 1 draw, or 2 pieces of pro, let alone most people. majid_sabet wrote: Do we feel safer with a gear rated 5 times more than what we could generate during a fall ? You have climbing gear rated to 80kn? I don't have any on my rack. Please tell me what gear you have that is rated to 80kn. Safety standards in climbing ? You mean something that is well documented and has been approved as standard ? Like how to jumar or what belay device you must use or you can not rap with rope under this size etc ? YA..................I need very specific well documented,peer reviewed standards.Let's get the government involved. When I go climbing I won't have to think anymore! Give me a break! Aren't my zero's rated to 80KN?
|
|
|
|
|
jmvc
Feb 16, 2008, 11:12 AM
Post #33 of 72
(1084 views)
Shortcut
Registered: Sep 10, 2007
Posts: 647
|
jt512 wrote: dobson wrote: In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. These threads are so predictable. F = ma. Let a = g. Then F = mg = w. Thus weight is a force. Jay Yup, but mass is not, and dobson was talking about mass. You measure wheight in newtons, not lbs. Not important anyway, I'm sure we all understood what you meant, I just had to be a pedant
|
|
|
|
|
jmvc
Feb 16, 2008, 11:28 AM
Post #34 of 72
(1082 views)
Shortcut
Registered: Sep 10, 2007
Posts: 647
|
d1r73 wrote: And yet we still hear of gear failures. I know I have heard of biners snapping on slacklines, harnesses failing, cams breaking, ropes snapping... etc etc I will give you that most of this was probably improper use and/or excessive wear and tear, but mfg know this shit happens and therefore build to account for a certain degree of stupidity/cheapness/laziness/misuses by the users. Also it's nice to have gear that is OBVIOUSLY way too worn to be using before it fails structurally. Yeah, that happened to me, i twisted my rope through a fig8 and it snapped.. that's why I changed to an ATC..
|
|
|
|
|
hugepedro
Feb 16, 2008, 11:34 AM
Post #35 of 72
(1080 views)
Shortcut
Registered: May 28, 2002
Posts: 2875
|
Yes, I just told you one standard, did you not read my post? Have you never heard of the EN standards? Or the UIAA? A standard for how to jumar? That's like asking if there is a standard for how to turn on a light switch. A standard for what belay device you must use? Why would there be? But next time you pick up your belay device note the little "CE" stamp on it. That is a standard. Every single piece of gear on your rack complies with a "well documented and approved" standard.
|
|
|
|
|
petsfed
Feb 16, 2008, 4:24 PM
Post #37 of 72
(1059 views)
Shortcut
Registered: Sep 25, 2002
Posts: 8599
|
dobson wrote: In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. Pounds force (lbf) are an imperial unit of force, independent of gravity. One kn is ~225 lbf. Jesus Fucking Christ. You're retarded. Surprise surprise, 1lbf for presses on a scale the exact same amount as something that "weighs" 1 lb. The imperial unit for mass is the slug. 1 slug weighs 32.2 pounds, and it takes 32.2 lbs of force to accelerate one slug of anything commensurate to gravity, eg at 32.2 ft per second per second. Join the modern (eg post 1650s) world of physics where weight = force. Its called Galilean relativity, and you probably learned in the 5th grade.
|
|
|
|
|
jt512
Feb 16, 2008, 5:28 PM
Post #38 of 72
(1048 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
jmvc wrote: jt512 wrote: dobson wrote: In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. These threads are so predictable. F = ma. Let a = g. Then F = mg = w. Thus weight is a force. Jay Yup, but mass is not, and dobson was talking about mass. You measure wheight in newtons, not lbs. Not important anyway, I'm sure we all understood what you meant, I just had to be a pedant If you're going to be pedantic, you should avoid being wrong. dobson clearly stated that pounds are a "unit of weight". And the pound is most certainly a unit of force. Jay
(This post was edited by jt512 on Feb 16, 2008, 5:30 PM)
|
|
|
|
|
jt512
Feb 16, 2008, 5:57 PM
Post #39 of 72
(1033 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
chalker7 wrote: jt512 wrote: No. There is no such thing as "dynamic force." There is just "force." I would think that the reason that the NFPA does not use the unit kN is because they are a U.S. organization, and hence they use the U.S. unit of force, the pound. Jay Thanks for the correction. When I said dynamic force, I think I should have been saying shock loading. Is shock loading measured differently than other kinds of force, i.e. a different unit? No. Force is force. Any force can be measured in either kN or lb. It's just that kN is a metric unit, and no one in the U.S. knows what a kN is unless they've taken a physics class, and most of them still don't get it.
In reply to: I'm not arguing I'm just asking, because the way I understand it a 225 lb or 1kN person does not weigh in at 1kN when loading the rope immediately after a fall, while they still weigh 225 lbs. Or am I misusing weight for mass in that scenario? Neither. You're misunderstanding the physics altogether. Weight is mass times the acceleration due to gravity; w = mg. A person's mass is the same everywhere in the Universe, and gravity is, for all practical purposes, the same everywhere on the earth. So person's weight is the same everywhere on the earth. Nothing in the above has to do with whether the person is falling, stationary, or is getting caught by a dynamic climbing rope. So his weight is the same. Here's the deal. When you want to stop a falling climber, you have to apply a stopping, or braking, force that is greater than his weight (weight is a force) in order to stop him. If you apply a force less than his weight, you'll only reduce his acceleration; if you apply a force equal to his weight, you'll stop his acceleration, but he'll continue falling at a constant speed. Thus you have to apply a force greater than his weight. If you lock off the belay device, the tension in the rope is this stopping force. Force = mass times acceleration. Since the climber is stopped over just a few feet of rope stretch, the acceleration is pretty high; and, since force = mass times acceleration, the force is pretty high. It is this force that is the impact force that you're thinking of. It's not the climber's weight that changes, it's the braking force that is required to stop the climber's fall. Jay
|
|
|
|
|
kachoong
Feb 16, 2008, 6:02 PM
Post #40 of 72
(1032 views)
Shortcut
Registered: Jan 23, 2004
Posts: 15304
|
jt512 wrote: dobson wrote: In reply to: kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately). Pounds (lb) are not a unit of force, they're a unit of weight; mass*g. These threads are so predictable. F = ma. Let a = g. Then F = mg = w. Thus weight is a force. Jay This is correct! We area always falling... it's just the ground that always gets in the way. Majid.... compliments on a good topic to bounce around.
|
|
|
|
|
chalker7
Feb 16, 2008, 9:19 PM
Post #41 of 72
(1018 views)
Shortcut
Registered: Mar 18, 2003
Posts: 317
|
Thanks Jay.
|
|
|
|
|
majid_sabet
Feb 17, 2008, 3:07 AM
Post #42 of 72
(993 views)
Shortcut
Registered: Dec 13, 2002
Posts: 8390
|
hugepedro wrote: Yes, I just told you one standard, did you not read my post? Have you never heard of the EN standards? Or the UIAA? A standard for how to jumar? That's like asking if there is a standard for how to turn on a light switch. A standard for what belay device you must use? Why would there be? But next time you pick up your belay device note the little "CE" stamp on it. That is a standard. Every single piece of gear on your rack complies with a "well documented and approved" standard. CE, EU , UIAA, etc qualifies climbing equipment and set requirements for such qualifications. Standards are sets of protocols that must be followed for certain equipment. For example, UL sets qualification for electrical equipment sold in USA. This means that a light bulb must meet certain requirements to be qualify as a light bulb . The department of urban and hosing sets standards so the particular light bulb must be installed in whatever ways in a residential housing. When a biner is made in Europe, to market such product, the biner must meet certine requirement and UIAA is one of the agencies that qualifies such equpiment. UIAA does not tell what to use when climbing. Climbing standard means that some agency ( not privet club or NGOs, NPOs) enforces a set of minimum requirement related to particular part in climbing.An example would be like an agencies says" To rappel, you must use whatever in such format and this is how it is done". in USA, the military and some of the fire, rescue agencies are the closest group of people who have partial standards but not on everything. As far as I know, there are no climbing standards that specifies how to climb or what to use when climbing.John Long's book ain't standard in anchor set up. Petzl drawing and the Mountaineering 5th addition are not standards and AAC for sure does not set standards on climbing. Is fig 8 the official standard for knot on TR ? Is Grigri the standard for big wall belay ? The 17" tire on a SUV is pretty standard and approved by DOT. You changed that to a 19" and you are SOL with nothing to back you up once you roll you car. Some one help the brother and show me some standards in climbing ( not standards in climbing equipment) .A well documented piece of standard that has been approved by an agency about climbing.
(This post was edited by majid_sabet on Feb 17, 2008, 9:22 AM)
|
|
|
|
|
patto
Feb 17, 2008, 6:16 AM
Post #43 of 72
(966 views)
Shortcut
Registered: Nov 15, 2005
Posts: 1453
|
I don't know what your arguements about safety standards are trying to prove. Standards whether it is food, safety or industry operations can be about making life simpler, more compatible or involve less decision making. Safety standard can remove decision making. It can mean that people who do not really have a clue about forces, or dangerous chemicals still safely operate in such environment. Climbing however is not a world of standards. There are too many variables and too many decisions need to be made that by promoting standards you can get people into trouble. Case in point is some sport climbers who find themselves in unusual situations be it rescues or other problems. I have seen some sport climbers totally clueless outside of belayin, clipping and heading down again.
|
|
|
|
|
majid_sabet
Feb 17, 2008, 9:29 AM
Post #44 of 72
(948 views)
Shortcut
Registered: Dec 13, 2002
Posts: 8390
|
patto wrote: I don't know what your arguements about safety standards are trying to prove. Standards whether it is food, safety or industry operations can be about making life simpler, more compatible or involve less decision making. Safety standard can remove decision making. It can mean that people who do not really have a clue about forces, or dangerous chemicals still safely operate in such environment. Climbing however is not a world of standards. There are too many variables and too many decisions need to be made that by promoting standards you can get people into trouble. Case in point is some sport climbers who find themselves in unusual situations be it rescues or other problems. I have seen some sport climbers totally clueless outside of belayin, clipping and heading down again. I have no arguments other that saying that there great deal of standards on climbing equipment but not a single standard related to climbing by itself. Something that says" this is how you have to belay in gym or if you are rapping with two ropes, you must use such knots to tie two ends".
|
|
|
|
|
hugepedro
Feb 17, 2008, 12:03 PM
Post #45 of 72
(936 views)
Shortcut
Registered: May 28, 2002
Posts: 2875
|
majid_sabet wrote: CE, EU , UIAA, etc qualifies climbing equipment and set requirements for . . . blah blah blah yada yada yada. #1 - Duh. Yeah. Tell me something I don't know. #2 - The kind of standards you are yammering on about (and what you're talking about would more commonly be considered policies rather than standards, but that's another argument) would imply the need for or existence of a climbing governing body of some sort. Are you advocating for such standards or such a body? #3 - Do you actually have a point? Or are you just going to keep on blah blah blahing about nothing of consequence? Because if you have a point it would be nice if you made it, because this is getting tedious and boring.
|
|
|
|
|
majid_sabet
Feb 17, 2008, 10:40 PM
Post #46 of 72
(914 views)
Shortcut
Registered: Dec 13, 2002
Posts: 8390
|
hugepedro wrote: majid_sabet wrote: CE, EU , UIAA, etc qualifies climbing equipment and set requirements for . . . blah blah blah yada yada yada. #1 - Duh. Yeah. Tell me something I don't know. #2 - The kind of standards you are yammering on about (and what you're talking about would more commonly be considered policies rather than standards, but that's another argument) would imply the need for or existence of a climbing governing body of some sort. Are you advocating for such standards or such a body? #3 - Do you actually have a point? Or are you just going to keep on blah blah blahing about nothing of consequence? Because if you have a point it would be nice if you made it, because this is getting tedious and boring. I do have a point . THERE ARE NO STANDARDS IN CLIMBING. Please reply when you find some standards for me.
|
|
|
|
|
philbox
Moderator
Feb 18, 2008, 2:25 AM
Post #47 of 72
(891 views)
Shortcut
Registered: Jun 27, 2002
Posts: 13105
|
majid_sabet wrote: hugepedro wrote: majid_sabet wrote: CE, EU , UIAA, etc qualifies climbing equipment and set requirements for . . . blah blah blah yada yada yada. #1 - Duh. Yeah. Tell me something I don't know. #2 - The kind of standards you are yammering on about (and what you're talking about would more commonly be considered policies rather than standards, but that's another argument) would imply the need for or existence of a climbing governing body of some sort. Are you advocating for such standards or such a body? #3 - Do you actually have a point? Or are you just going to keep on blah blah blahing about nothing of consequence? Because if you have a point it would be nice if you made it, because this is getting tedious and boring. I do have a point . THERE ARE NO STANDARDS IN CLIMBING. Please reply when you find some standards for me. Nor should there ever be official mandated government standards for climbing. There are however non official standards for climbing and they have been established in the court of public opinion. For instance, the climbing community has established that it would be wise to climb whilst attached to a climbing rope with a knot that is sufficient for the job whilst also being belayed by a competent belayer. The climbing community also has mandated that it is a good idea to keep two pieces of gear between the climber and doom. The same can be said of anchoring systems and placement of gear. Our standards are established by way of precedent. We push the boundaries and either fall to our doom or invent new ways and devices to keep ourselves from falling to our doom. In recreational pursuits there should never ever be a place where official bodies come in and mandate how we recreate. That would be the death of our sport/passion/pursuit. Innovation would be stultified or crippled. Best we be free to learn from our own and others mistakes. The lessons are learned by way of dissemination of that information. In OHSA circles the information gathered from death and injury by and large is kept under lock and key so to speak due to the litigous nature of that system. Please do not advocate that we go down that road.
|
|
|
|
|
philbox
Moderator
Feb 18, 2008, 2:35 AM
Post #48 of 72
(887 views)
Shortcut
Registered: Jun 27, 2002
Posts: 13105
|
Hey jt, is there ever a need to state that there is deceleration as opposed to the word acceleration when considering the forces involved with stopping a climbers fall. Would not deceleration be a better descriptive word? I know that when a climber is initially falling then acceleration would be the best term to use but when a belayer applies a frictional force to the rope would not the climber then be decelerating. Just trying to get my terminology correct and I would love to hear your opinion on this. I have used the term deceleration in the past and am wondering if I have been in error.
|
|
|
|
|
hugepedro
Feb 18, 2008, 4:25 AM
Post #49 of 72
(879 views)
Shortcut
Registered: May 28, 2002
Posts: 2875
|
Phil, you make a good point, those would be de facto standards, eh?
majid_sabet wrote: I do have a point . THERE ARE NO STANDARDS IN CLIMBING. Please reply when you find some standards for me. That's not a point, that just a statement, the proper response to which is, so what? Now if you can give a reasonably interesting answer to the "so what" question than you might have a point. Otherwise this thread is . . . pointless.
|
|
|
|
|
petsfed
Feb 18, 2008, 5:26 PM
Post #50 of 72
(1366 views)
Shortcut
Registered: Sep 25, 2002
Posts: 8599
|
philbox wrote: Hey jt, is there ever a need to state that there is deceleration as opposed to the word acceleration when considering the forces involved with stopping a climbers fall. Would not deceleration be a better descriptive word? I know that when a climber is initially falling then acceleration would be the best term to use but when a belayer applies a frictional force to the rope would not the climber then be decelerating. The only reason I've seen terminology used like that is to explicitly state the vector direction of the acceleration in terms of the velocity. That is, in acceleration, the force vector is parallel to the velocity vector, whereas in deceleration the force vector is antiparallel to the velocity vector. In common usage, I've found that deceleration implies that when the velocity equals zero, the force also becomes zero. That is, a car is said to decelerate if, after its velocity reaches zero, it does not start going in the opposite direction. But that's just from reading waaay too many physics textbooks.
|
|
|
|
|
|
|
|
|