UKH

Hi,

I am doing some maths research for my IB (International Baccalaureate) and I need some data. I was wondering if anyone has any data on the maximum breaking points on (a preferably large quantity) of ropes. I need this data to see if it meets with the 3-sigma rating. The 3-sigma rating means that these rated products are 99.9% stronger than the average MBS rating (minimum breaking load). This means that a 3-sigma rated MBS is 3 standard deviations below the average breaking strength. 

This data is purely for academic use and it will not be displayed anywhere other than my research paper. 

Many Thanks, it is very much appreciated.

Climbing ropes aren´t tested to breaking strength in the way you are thinking, you´ll have to try another industry or application for that kind of data.

As Jim has mentioned above, you won't get that data for ropes as it isn't recorded/ tested for. I would recommend looking at Nuts, more specifically the Wild Country Rocks as they had an enormous product recall a few years ago due to not having sufficient confidence in the manufactured strength of their own product!

https://www.thebmc.co.uk/wild-country-rocks-recall

You may be able to get a large chunk of data by getting intouch with Wild Country/ Salewa.

Have you tried contacting DMM they use 3 sigma rating?

Although I doubt any manufacturer would pass this data to anyone even for educational purposes.

You're best to ask a rope manufacturer directly I think.

Just to demonstrate my extreme pedantry that's 99.7% not 99.9% by the way.

What's the specified minimum breaking force for a climbing rope?

jk

There isn't one but I vaguely remember somwhere like 3.7kN would theoretically get through. Fairly sure when Sterling tested some about 8.7kN was bottom line.

Hard to believe any company would actually release their data!

You planning on giving up your day job and becoming a comedian? Every person who was involved in the recall has left the company...

I'm sure they'd love to tell the world exactly how useless 3- sigma can be as a QA system!

I'm sure there are a few from BD who could tell a tale too after the recall debacle they had too... infact it's most companies these days...

Had an entertaining discussion once with someone from the UIAA about all the companies with recalls had a common factor, 3 sigma AND iso 9001. Paperwork is no sustitute for engineering.

If companies spent as much as they spend on marketing and show stands on QC...

Spending money on quality, and having more documentation than you can eat still doesn't mean anything if people don't have a good understanding of what they are doing! Training is the bit a lot of businesses seem to screw up in my experience.