16. What is "sharp edge resistance"?
There are no documented cases of a rope breaking under "normal use". The documented occurrences of rope breakages in the field are attributed to pre-exposure to sulfuric acid or by being cut by a sharp edge. UIAA just recently added an optional test to UIAA 101 for testing to sharp edge resistance (UIAA 108). Many manufacturers are claiming sharp edge resistance for their ropes. The designation of sharp edge resistance is not a guarantee of safety. These ropes can still be cut. Our in-house testing shows that slight variables in the testing procedure can cause even "edge safe resistant" ropes to break on the first fall. APAVE, the UIAA Approved Lab that we use for testing has recently issued a statement, that their "insurance company strongly recommend us to inform our customers that this test does not reproduce the reality and that the behavior of a rope in contact with a sharp edge can be radically different from the UIAA 108 test conditions and results."

17. How many meters to feet?
1 meter = 3.28 feet

18. How much is a Kilonewton?
1 Kilonewton = 224.82 Lbs Force

19. What is Impact Force?
Impact force is the force felt by the climber or rescuer and equipment at the termination of a fall. It is also the number that is used to show a rope's ability to absorb the energy created during that fall. A fall on static rope with little elongation and a fixed anchor point will generate much higher impact forces than a fall on dynamic rope using a dynamic belay. There are two measures of impact force. Theoretical impact force is the impact force without any extraneous variables. Actual impact force is the force created when you take into account a dynamic belay and friction developed over both the carabiners and rock. The UIAA mandates that the impact force generated on the first fall must be less than 12kN for a single rope. This test uses a static belay with a fall factor of approximately 1.8 or a 4.5 meter (@15') fall on 2.5 meters (@8') of rope. This test demonstrates a very severe fall and generally is not applicable for real world climbing situation but does give a good basis for comparing the relative elongation characteristics of different ropes. Real world experience has shown that rarely are impact forces higher than 10kN generated during a climbing fall. Ultimately there are many factors that affect the impact force felt by a climber or rescuer and in order to limit those forces it is important to place protection whenever possible and to utilize a dynamic belay.

Next time we will continue to work on answering Frequently Asked Questions.

Until next time, be safe and always dress your knots!

STERLING ROPE and AHS Rescue