Without getting overly mathematical and putting it into its simplest terms the Fall Factor is the ratio of the distance you fall to the length of the rope measured from the last anchor point or from where the rope was last clipped into protection.
A simple calculation for Fall Factor is represented in the table below:
| Fall factor = | Length Of Fall |
------------------ |
|
Length Of Rope Out |
Fall Factor is measured from 0 to 2, where fall factor of 0.5 is light, 1 is moderate, and a Fall Factor of 2 is serious to the point of death.
Fall Factor |
Severity |
0 |
Non |
0.1 |
|
0.2 |
|
0.3 |
|
0.4 |
|
0.5 |
Light |
0.6 |
|
0.7 |
|
0.8 |
|
0.9 |
|
1 |
Moderate |
1.1 |
|
1.2 |
|
1.3 |
|
1.4 |
|
1.5 |
Severe |
1.6 |
|
1.7 |
|
1.8 |
|
1.9 |
|
2 |
Fatal |
The force of your shock is dependent upon the fall factor, your weight, and the type of rope you use. Dynamic rope considerably decreases the shock a climber feels because it has the ability to stretch and absorb more of the force. The maximum Fall Factor possible is Fall Factor 2. The definition of Fall Factor 2 is a climber who falls the complete length of a rope used i.e. a lead climber falls before clipping into protection and falls past the anchor point or his second who is belaying him on the rock face.
Fall Factor is simply the distance or length of the fall divided by the length of the rope from the falling climber to the climber’s last fixed point, whether that is the belayer or anchor point/protection clipped into.
Shock Force
The expression Shock Force is a term given to conditions added to the Fall Factor of a climber. These factors are the climber’s weight and the type of rope used. A heavier climber will exert more stress on a rope. A climber falling with a static rope will have more shock concentrated at the two end points of the rope. Those points being the climbers harness and therefore the climber’s skeletal structure and the anchor point at the other end of the rope. The reason being that unlike a dynamic rope, which allows stretch, a static rope cannot dissipate any of the shock and energy of the impact because it cannot stretch. The table below shows the clear difference of shock force between Static and Dynamic ropes:
| Rope Type | Static |
Dynamic |
| Weight of climber (kg) | 80 |
80 |
| Length of Rope (metres) | 20 |
20 |
| Distance from last anchor point (metres) | 4 |
4 |
| Fall Factor | 1.2 |
1.2 |
| Shock Force (Kilo-Newtons) | 10.79 |
5.39 |
The shock force is double in the static rope compared to the dynamic.
For a comprehensive Shock Force calculator go to: http://www.myoan.net/climbart/climbforcecal.html
