Load ratings of climbing equipment?

[pdqdl]

Do you ever wonder how much weight your climbing equipment is rated for? If you look real close, most hardware has a number stamped on it followed by a "Kn". This stands for Kilonewtons.

While this isn't exactly proper physics, one Kilonewton is equal to 225 lbs (actually 224.808942443 lbs)

So that 27Kn carabiner should be rated to hold a force of over 6,000 lbs.


*******************************************************
Of course the folks that don't use the "English common" weight system won't be concerned with that problem, as they will be converting kilograms... One Kilonewton =102Kg (Actually 101.64525412649).

So that 27Kn carabiner should be rated to hold a force of over 2,700Kg.
(I wonder why the conversion is not an exact multiple of 10 ?)

 

[RacerX]

Do you ever wonder how much weight your climbing equipment is rated for? If you look real close, most hardware has a number stamped on it followed by a "Kn". This stands for Kilonewtons.

While this isn't exactly proper physics, one Kilonewton is equal to 225 lbs (actually 224.808942443 lbs)

So that 27Kn carabiner should be rated to hold a force of over 6,000 lbs.


*******************************************************
Of course the folks that don't use the "English common" weight system won't be concerned with that problem, as they will be converting kilograms... One Kilonewton =102Kg (Actually 101.64525412649).

So that 27Kn carabiner should be rated to hold a force of over 2,700Kg.
(I wonder why the conversion is not an exact multiple of 10 ?)

Care to explain what you're questioning?

 

[jefflovstrom]

:monkey:
Jeff

 

[treemandan]

It's not that I wonder about the load rating on the gear but more-so wonder if I fell asleep and woke up in Europe. I swear one day I am gonna kill that Dewey Decimel son of a #####.

 

[ArborSmithNw]

It's not that I wonder about the load rating on the gear but more-so wonder if I fell asleep and woke up in Europe. I swear one day I am gonna kill that Dewey Decimel son of a #####.

Close.
It's more that the manufacturers woke up and started selling more here in the states, the cost or restamping dies must be too great (plus the french are too proud a people to change things for Zee ozer people'z)

 

[treevet]

My biggest worry is the ability to withstand shock load by all these contemporary devices such as microcenders, ascenders, rope grabs and the like. If some lard ass falls off a limb and after two or 5 feet before engaging, the device is all that is to save him being the weak link in the chain....somebody is in big trouble. I have also read of some instances that rope grabs when shock loaded have severed support lines.

 

[John Paul Sanborn]

I swear one day I am gonna kill that Dewey Decimel son of a #####.

What does a library card catalog have to do with anything

Britannica Concise Encyclopedia:
Dewey Decimal Classification


System for organizing the contents of a library based on the division of all knowledge into 10 groups. Each group is assigned 100 numbers. Subdivisions eventually extend into decimal numbers; for example, the history of England is placed at 942, the history of the Stuart period at 942.06, and the history of the English Commonwealth at 942.063. The system was first formulated in 1873 by Melvil Dewey. Many libraries add a book number created from the Cutter-Sanborn, Tables, which further specify author and genre. The Library of Congress Classification has largely replaced the Dewey system.

 

[treemandan]

What does a library card catalog have to do with anything

Dam you Dewey, dam you!

 

[pdqdl]

Care to explain what you're questioning?

Notice that the conversion factor for Kilonewtons is NOT an even multiple of 10; rather, it is 101.64525412649. The whole purpose of the metric system is to keep things simple and easy to convert.

This small deviation is not enough to make much difference to most folks, but it points out to me that there is some facet of the kilonewtons (force) to Kilograms (mass) conversion that I do not know or understand. I suspect that it is related to the acceleration due to gravity, but I am not sure.
(defined to be precisely 9.80665 m/s2 )

 

[tree MDS]

My biggest worry is the ability to withstand shock load by all these contemporary devices such as microcenders, ascenders, rope grabs and the like. If some lard ass falls off a limb and after two or 5 feet before engaging, the device is all that is to save him being the weak link in the chain....somebody is in big trouble. I have also read of some instances that rope grabs when shock loaded have severed support lines.

I worry about the micro ascender on my lanyard when I have to push a top or log real hard. Its in the heat of that moment that thoughts like this enter my mind...is this thing really that tough? is it made for this sort of abuse?? I realize this can be avoided by simply putting a rope in the piece, but I'm just being real here. It happens.

 

[JeffL]

My biggest worry is whether or not my spine will withstand a 4 or 5 foot fall and shockload.

 

[tree MDS]

My biggest worry is whether or not my spine will withstand a 4 or 5 foot fall and shockload.

Still better than shockloading the pavement coming from 50' up.

 

[treevet]

Do you ever wonder how much weight your climbing

While this isn't exactly proper physics, one Kilonewton is equal to 225 lbs (actually 224.808942443 lbs)

So that 27Kn carabiner should be rated to hold a force of over 6,000 lbs.

Well since we are talking climbing gear and not many fat asses even come close to tipping the scales at 6000 lbs we are obviously talking shock load here. I can just picture our friends at ANSI sitting around a big table and Joe says...."Let's make sure a fat ass that slips off a limb and hasn't pulled up slack will fall 5 feet and be ok .....but if he falls 6 feet....well....maybe he deserves it.

 

[John Paul Sanborn]

My understanding of the ANSI load ratings was that these were the SWL of the then available product, e.g. ropes and snaps. People wanted Arborplex to be adopted as the minimum standard.

 

[treevet]

My understanding of the ANSI load ratings was that these were the SWL of the then available product, e.g. ropes and snaps. People wanted Arborplex to be adopted as the minimum standard.

Boy, that Arborplex was (is?) some miserable stuff. We used to call it "garbor plex"

If they haven't yet rated all these mechanical ascend/descend devices at ANSI they will soon I'm sure. On a slip off a branch or spike peel out I would take my NE Safety Blue w/ taughtline anyday over a miniscender, uniscender, grillon, or any of these exotics but I still use em. How often do you inspect the block that is taking half a leader on shock load over the middle of a house with a slate roof?. We love the thrill and danger of the unknown (unsure) and tee it up and let her fly. What a rush.

most of the time we are working on educated guesses

 

[treemandan]

I went down about 10 feet til my srt line found a crotch it liked better. I was tied to the rope with a Petzl hand ascender, no problem.

 

[ArborSmithNw]

Would it help to know that the load ratings stamped on the gear are something like 40% lower than the actual breaking point? So even a 825 pound fella should be cool! And to me, ANY man that size would be cool, imagine the logs that grunt could shoulder!!!

The one thing that you have to worry about in addition to improper usage is large gouges in the aluminum, they can lead to micro-fractures and cause the piece to fail.

 

[outofmytree]

In physics, force is what changes or tends to change a state of rest or motion in an object. Force causes objects to accelerate, add to the object's overall pressure, or change direction. Force is measured in Newtons (N).

Force has both magnitude and direction, making it a vector quantity.

In english then, force is variable and mass is not. So you cannot use the same measure for both. Newtons for force and pounds/kilograms for mass.

 

[John Paul Sanborn]

In english then, force is variable and mass is not. So you cannot use the same measure for both. Newtons for force and pounds/kilograms for mass.

Since mass and weight are the same here on Mother Earth, isn't it the same in our applications?

 

[SINGLE-JACK]

Notice that the conversion factor for Kilonewtons is NOT an even multiple of 10; rather, it is 101.64525412649. The whole purpose of the metric system is to keep things simple and easy to convert.

This small deviation is not enough to make much difference to most folks, but it points out to me that there is some facet of the kilonewtons (force) to Kilograms (mass) conversion that I do not know or understand. I suspect that it is related to the acceleration due to gravity, but I am not sure.
(defined to be precisely 9.80665 m/s2 )

"The whole purpose of the metric system is to keep things simple ..."

Well, it is intended to be simple WITHIN the metric system = Meter-Kilogram-Second (MKS) system:

1 Newton is defined in the MKS system as the force necessary to provide a mass of 1 Kilogram with an acceleration of 1 Meter per Second per Second, which is simple enough.

1 kiloGram is defined as the force of gravity on the International Prototype Kilogram which is almost exactly equal to the mass of one liter of water, which is simple enough.

The "small deviation" (101.64525412649) is due to the difference in the force of gravity on the International Prototype Kilogram and the force to accelerate the International Prototype Kilogram to 1 Meter per Second per Second. The inverse is referred to as the Gravitational Constant, "9.80665 m/s2".

1 kiloNewton = 1000 Newtons

However: "... easy to convert." ... not so much!

Conversion from the MKS system to the “English” Foot-Pound-Second (FPS) system is simple with a single conversion factor, just not straight forward:*

1 Pound-force is defined in the FPS system as the force necessary to provide a mass of 1 Slug with an acceleration of 1 Foot per Second per Second.

1 Slug = 32.174048556 Pounds-mass (MKS system ~ 9.80665)
1 Kilogram = 2.20462262185 Pounds-force
1 Meter = 3.2808399 Feet

1 kiloNewton = 1000 X 2.20462262185 X 3.2808399 / 32.174048556

1 kiloNewton = 224.8089434 Pounds-force ~ 225 Pounds


*Ref: Ed Gohmann, Purdue University School of Technology

Supposition: Maybe the risk of confusion about pound-mass and pound-force (yada-yada) caused some lawyers somewhere to mandate the use of kiloNewtons so there would be no confusion.
:monkey: