הבדלים בין גרסאות בדף "Single Point of Failure"

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(דף חדש: A '''Single Point of Failure''' or '''SPOF''' is a point in a system (in our case, a rope system), that if it fails, the whole system fails. The idea of Single Points of Fail...)
 
 
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שורה 1: שורה 1:
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{{LTR}}
  
A '''Single Point of Failure''' or '''SPOF''' is a point in a system (in our case, a [[ropes|rope]] system), that if it fails, the whole system fails. The idea of Single Points of Failure
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[[נקודה קריטית]]
is the basic concept in understanding the applcation of backup in rope work.
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A '''Single Point of Failure''' or '''SPOF''' is a point in a system (in our case, a [[ropes|rope]] system), that if it fails, the whole system fails. The idea of Single Points of Failure is the basic concept in understanding the application of backup in rope work.
  
 
"Even though it contains the word "single", a system may have multiple SPOPF.
 
"Even though it contains the word "single", a system may have multiple SPOPF.
  
* In many cases, the human is a SPOF. Two obvious examples are the [[belay|belayer]] in [[top rope]] and [[rappelling]] with a prussik.
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* In many cases, the human is an SPOF. Two obvious examples are the [[belay|belayer]] in [[top rope]] and [[rappelling]] with a [[prussik]].
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In [[rope rescue]] situations it is recommended not to have any single points of failure. We eliminate SPOFs by doubling the systems, coupling them or simply backing them up. In climbing, rappelling and [[canyoning]] there usually are SPOFs that cannot be eliminated for reasons of practicality and ease of use. Some SPOFs are intentional, like when rapping of a [[trad]] [[route]].
  
In rescue situations it is recommended not to have any single points of failure. We eliminate SPOFs by doubling the systems, coupling them or simply backing them up. In climbing, rappelling and canyoning there usually are SPOFs that cannot be elliminatedfor reasons of practicality and ]]ease of use. Some SPOFs are intentional, like when rapping of a [[trad ro
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A useful exercise for understanding SPOFs is:
  
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List all the SPOFs in a top rope system (solution can be found [[SPOF exercise|here]]).
  
A useful exercise for understanding SPOFs is:
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When the system is build, SPOFs should be analyzed, evaluated and, if needed, eliminated. We know that most failures are due to human errors, either by misjudgment, by wrong application of parts of the system, or by using an altogether unsuitable technique or pieces of gear. A negligible fraction of accidents are due to gear failure.
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==different approaches to backing up==
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There are two basic approaches to backup in a rope system:
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===backup only where it's needed===
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The first approach is to backing up only where backup is needed. This decision is in the hands of the person who sets up the rig. According to that perception, whether to backup and the mode of backing up are subjective and are highly dependent upon the rigger, his skills and experience, and on the way he sees the dangers.
  
List all the SPOFs in a top rope system (solution can be found [[SPOF exercise|here]].
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the points that need backup are of two types:
  
When the system is build, SPOFs should be analyzed, evaluated and, if needed, eliminated. We know that
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1. Points that have a higher chance for gear failure. For example:
על בונה המערכת לאתר את הנקודות הקריטיות ולבטלן במידת הצורך על ידי גיבוי. הסיבה העיקרית לכשלים היא טעויות אנוש כתוצאה מיישום לא נכון של חלקי המערכת או צורת עבודה לא נכונה או שאינה מתאימה למערכת. מיעוט קטן ביותר של הכשלים נגרמים עקב כשל טכני של ציוד.
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*A [[Biner]]'s gate that is located on a rock edge is pushed against it and can accidentally open. In this case a second, [[reversed biners|reversed biner]] would be a proper backup.
==גישות שונות לגיבוי==
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*A [[webbing]] or [[rope]] that are loaded and pass over a sharp edge or corner with serious risk of cutting. In that case, a second, unloaded (a little longer) rope or webbing will do the trick.
קיימות שתי גישות כלליות לגיבויים במערכות חבלים:
 
===גיבוי נקודתי===
 
גישה ראשונה היא לגבות רק במקום בו (לדעת בונה המערכת) הגיבוי נחוץ. על פי שיטה זו יישום הגיבוי הוא סובייקטיבי ותלוי במי שבונה את המערכת, במידת מיומנותו ובהערכתו את הסיכונים במערכת.
 
  
על פי גישה זו מגבים רק נקודות בעייתיות משני סוגים:
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2. Points that are prone to failure due to human error. For example:
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* A locking biner on the [[harness]], that can get unlocked and potentially open. This is backed up wit another connection to the rope (prussik, for example).
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* When setting a [[belay]] on a trad route, we use more than one piece of pro.
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This approach, in general, requires a high level of skill and knowledge, and is more commonly found in personal activity as [[rock climbing]], [[alpinism]], [[caving]] and [[canyoning]]. These activities put a lot of emphasize on being lightweight and avoiding bulky systems. For example, it is not considered necessary to backup a a webbing or a biner that are hanging freely and do not touch rock or ice. The assumption is that the gear will not fail by itself.
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===always backup everything!===
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The second approach is to have a backup for each and every element in your system. This is looked upon as a rule and is done without using any judgement. Backing up everything minimizes the risk and especially the chances of human error.
  
1. מקומות בהם יש סיכון גבוה לכשל של ציוד. לדוגמה:
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This is an extreme statement, of course, and is ridiculous in a way. Backing up everything cannot be taken seriously because:
* [[טבעות|טבעת]] הנלחצת על הסלע, ועלולה להיפתח. במקרה כזה מגבים על ידי [[טבעות הפוכות]].
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# In most cases you simply cannot backup everything, and even if you could, it's not practical. That means you need to decide what does and what does not need backup, which contradicts the basic demand.
* [[רצועות|רצועה]] או חבל העוברים על פינת סלע במקום בו הסיכון לשחיקה או קריעה הוא ממשי. במקרה כזה מגבים על ידי רצועה או חבל, רפויים.
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# If you backup not all, but too many elements
2. נקודות אשר יש בהן סיכוי גבוה לכשל עקב טעות אנוש. לדוגמה:
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* your system becomes bulkier and confusing. This in itself makes you less safe, which again, works against the demand to backup to be safer.
* טבעות המחוברות ל[[רתמות|רתמה]] אשר יש סיכוי לפתיחתן בזמן השימוש. במקרה כזה מגבים על ידי חיבור נוסף לחבל.
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* you have too much stuff, which makes you slower on the route (in climbing and canyoning). If the weight is not a good enough argument, you also have to spend more time on setting belays and operating them, which also consumes time. Remember, [[fast]] is safe.
* [[אבני עיגון]] בתחנה. משתמשים ביותר מאבן עיגון אחת.
 
גישה זו דורשת רמת ידע ומיומנות גבוהה ונהוגה יותר בפעילות שטח עצמאית כגון טיפוס מצוקים, [[טיפוס אלפיני]], [[קניונינג]] ו[[מערנות]] (caving), כאשר יש חשיבות רבה למשקל הציוד ולפשטות המערכת וכך לדוגמא לא נהוג לגבות [[רצועות|סלינג תפור]] או [[טבעות|טבעת ננעלת]] הנמצאים ב[[חלוקת משקל]] בתחנה אשר כולה באוויר ללא מגע עם הסלע.
 
  
===גיבוי בכל מקום===
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So what do we do? we backup everything that is not excessively strong. So, all pieces of gear we backup, ropes, biners etc. We would not backup a large tree or a huge building as an anchor even if it is an SPOF.
הגישה השנייה היא לגבות את כל חלקי המערכת (למעט עיגון כגון [[שימוש בעצים כעיגונים בעבודת חבל|עץ ענק]] וכדו'), ללא הפעלת שיקול דעת, על מנת להקטין למינימום את הסיכון, בעיקר את האפשרות לטעות אנוש.
 
  
יש הטוענים, כי בכל מקרה עדיף לגבות הכל. טענה זו אינה רצינית, כי:
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The principle with this approach is to minimize the effect of the rigger's judgement and so avoid errors. This is common in courses and guided activities, as well as when working with a large number of people: large groups, rescue teams etc.
# אי אפשר במרבית המקרים, לגבות הכל, ואם אפשר - זה לא מעשי. זאת אומרת שצריך להחליט מה כן ומה לא לגבות, וזה עומד בסתירה לטענה המקורית.
 
# אם מגבים יותר דברים, מקבלים כי:
 
* משתמשים בהרבה יותר ציוד מכפי שנחוץ, והתוצאה היא בלאגן ועבודה מסורבלת. זה לכשלעצמו לא בטיחותי.
 
* לוקחים הרבה יותר ציוד, זה מאיט את ההתקדמות על המסלול (גם בקניונינג וגם בטיפוס), ואם זה לא מספיק - מבזבזים הרבה יותר מדי זמן על בניית תחנות ותפעול המערכות. גם ל[[מהירות]] ההתקדמות על המסלול השפעה מכרעת על הבטיחות הכללית.
 
  
העיקרון הוא, כפי שנאמר, למזער את השימוש בשיקול הדעת של בונה או מפעיל המערכת וכך למנוע טעויות. שיטה זו נהוגה במערכות המיועדות להדרכת והפעלת חניכים. גישה זו מקובלת גם ב[[יחידות חילוץ|חילוץ]]. גישה זו שולטת בכל הוראות הבטיחות של [[חוזר מנכ"ל]] משרד החינוך. על פי חוזר מנכ"ל, גישה זו מחוייבת בכל פעילויות החבלים לתלמידי בתי ספר, למעט מספר מקרים ספציפיים כגון טיפוס [[טופ-רופ]] בה לא ניתן ליישמה מטעמים מעשיים.
 
 
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תרמו לדף זה: [[משתמש:מיכה יניב|מיכה יניב]] ואחרים...
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Contributions to this page were made by [[user: Mica Yaniv|Mica Yaniv]] and others...
  
[[קטגוריה: כללי]][[קטגוריה: הגדרות]][[קטגוריה: טכניקות ומיומנויות]][[קטגוריה: טיפוס]][[קטגוריה: בטיחות]]
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[[category: glossary]][[category: skills and techniques]][[category: climbing]][[category: safety]]

גרסה אחרונה מ־06:59, 6 בספטמבר 2009

נקודה קריטית

A Single Point of Failure or SPOF is a point in a system (in our case, a rope system), that if it fails, the whole system fails. The idea of Single Points of Failure is the basic concept in understanding the application of backup in rope work.

"Even though it contains the word "single", a system may have multiple SPOPF.

In rope rescue situations it is recommended not to have any single points of failure. We eliminate SPOFs by doubling the systems, coupling them or simply backing them up. In climbing, rappelling and canyoning there usually are SPOFs that cannot be eliminated for reasons of practicality and ease of use. Some SPOFs are intentional, like when rapping of a trad route.

A useful exercise for understanding SPOFs is:

List all the SPOFs in a top rope system (solution can be found here).

When the system is build, SPOFs should be analyzed, evaluated and, if needed, eliminated. We know that most failures are due to human errors, either by misjudgment, by wrong application of parts of the system, or by using an altogether unsuitable technique or pieces of gear. A negligible fraction of accidents are due to gear failure.

different approaches to backing up

There are two basic approaches to backup in a rope system:

backup only where it's needed

The first approach is to backing up only where backup is needed. This decision is in the hands of the person who sets up the rig. According to that perception, whether to backup and the mode of backing up are subjective and are highly dependent upon the rigger, his skills and experience, and on the way he sees the dangers.

the points that need backup are of two types:

1. Points that have a higher chance for gear failure. For example:

  • A Biner's gate that is located on a rock edge is pushed against it and can accidentally open. In this case a second, reversed biner would be a proper backup.
  • A webbing or rope that are loaded and pass over a sharp edge or corner with serious risk of cutting. In that case, a second, unloaded (a little longer) rope or webbing will do the trick.

2. Points that are prone to failure due to human error. For example:

  • A locking biner on the harness, that can get unlocked and potentially open. This is backed up wit another connection to the rope (prussik, for example).
  • When setting a belay on a trad route, we use more than one piece of pro.

This approach, in general, requires a high level of skill and knowledge, and is more commonly found in personal activity as rock climbing, alpinism, caving and canyoning. These activities put a lot of emphasize on being lightweight and avoiding bulky systems. For example, it is not considered necessary to backup a a webbing or a biner that are hanging freely and do not touch rock or ice. The assumption is that the gear will not fail by itself.

always backup everything!

The second approach is to have a backup for each and every element in your system. This is looked upon as a rule and is done without using any judgement. Backing up everything minimizes the risk and especially the chances of human error.

This is an extreme statement, of course, and is ridiculous in a way. Backing up everything cannot be taken seriously because:

  1. In most cases you simply cannot backup everything, and even if you could, it's not practical. That means you need to decide what does and what does not need backup, which contradicts the basic demand.
  2. If you backup not all, but too many elements
  • your system becomes bulkier and confusing. This in itself makes you less safe, which again, works against the demand to backup to be safer.
  • you have too much stuff, which makes you slower on the route (in climbing and canyoning). If the weight is not a good enough argument, you also have to spend more time on setting belays and operating them, which also consumes time. Remember, fast is safe.

So what do we do? we backup everything that is not excessively strong. So, all pieces of gear we backup, ropes, biners etc. We would not backup a large tree or a huge building as an anchor even if it is an SPOF.

The principle with this approach is to minimize the effect of the rigger's judgement and so avoid errors. This is common in courses and guided activities, as well as when working with a large number of people: large groups, rescue teams etc.


Contributions to this page were made by Mica Yaniv and others...