Friction is important!

Friction in rope access gear, like gravity, is one of those things we have to deal with in rope access all the time. It can help us and on the other hand hinder us. In rope access we sometimes actually want friction to help us. For instance when lowering or descending, we can use friction to control our speed through our descent control devices or descenders. But when we start lifting things, the less friction we have, the easier we can defeat gravity.
In this post we will explore friction in our various every day rope access devices. This will tell us where to put which device in our system.
19 tests done and one thing is clear…. Things are not as efficient as they seem AND we have one surprise winner!

How are pulleys tested

(Edit 01-02-2022)
Apparently there is no set standard or testing method for manufacturers to use and which gives us the efficiencies. They can come to their numbers in whatever way they want. Some companies are more transparant than others on this. For instance Petzl have a post on their site which very clearly states their findings and how they tested. You can read that here:
Pulley system efficiency tests 

The numbers are pretty close to what I got and I think the stated efficiencies should be more of a general guide as to more or less efficient than another pulley. There are just to many variables.

I got pointed onto the Petzl testing by a post on the Facebook group of the Rope Test Lab which has got to be one of the best places to go for intelligent conversation on rope based activities. Usually linked to http://www.ropelab.com.au/ where all Richard’s research lives. Go check it out!

The Results

As it turns out, this is turning into one part of a larger video series on mechanical advantages and lifting systems, where the “Are we building out Z-Rig wrong” video might be considered as part one.
You can watch that here:
https://youtu.be/sIMFvf_E5Y8

Video’s mentioned:

Advanced Harness Setup
https://youtu.be/vZv3c4XNkUQ

Richard Delaney’s excellent post on friction:
https://www.ropelab.com.au/pulley-efficiency/
Yes, it is a member post and if you are interested in learning everything about the rope systems and mechanics we use, it is definitely worth it to become a member in my opinion.

Welcome video where I explain the philosophy behind The Rope Access Channel
https://youtu.be/x8vy50kzIsM

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Chapters

0:00 Intro on Friction
0:22 Testing setup explained
1:53 Test 1 Steel Carabiner
3:58 Test 2 Aluminum Carabiner
4:38 Test 3 Small Skalt Pulley
5:28 Test 4 Cresto Pulley
6:23 Test 5 Petzl Mini Traxion
7:03 Test 6 Petzl Rollclip A
7:57 Test 7 Rock Exotica Omni Block 1.1
8:56 Test 8 Petzl Rescue
9:40 Test 9 Petzl Micro Traxion
10:15 Linescale LS3 Discount
10:47 Test 10 Petzl Pro Traxion
11:20 Test 11 Petzl I’D
12:12 Testing Considerations
13:33 Test 12 Climbing Technology Sparrow R
14:46 Test 13 Petzl Rig
15:42 Test 14 ISC D4
16:51 Test 15 Petzl I’D Evac
17:40 Test 16 Skylotec Sirius
18:26 Test 17 TAZ Lov2
19:19 Test 18 Petzl Maestro
20:09 Test 19 CMC/Harken Clutch
20:20 Concluding Thoughts