It is well known that falls from height still remain the single biggest cause of fatalities on site and in the workplace. The force of gravity means that we accelerate earthwards at 32 feet/second/second and the force we hit the ground with increases very rapidly with height.
The factors involved are the force of gravity, the height of the fall, the weight of the individual and just how much the fall is cushioned on impact. This means that the greater the height, the heavier the individual and the less yielding the surface, the greater the force of impact.
Just enter a height of fall, your weight and assume a stopping distance and the Terminal Force Calculator will assess your chances of survival. Assume 1cm stopping distance for concrete (the body has some natural padding) and 50 cms for an inflatable fall arrest bags such as AirDeck.
A fall from metre doesn’t sound much, but dropping as a dead weight, an 80kg man could encounter a force of 100g if falling onto concrete.
To put this into context, in a car crash, a passenger may experience as much as 50g deceleration, and, if secured by a seatbelt could come away with only superficial injuries. At 75g deceleration, the expected fatality rate is 50%. Deceleration over 80g is considered to be always fatal.
Treat height with respect.
What height would you have to fall from for your terminal force to exceed 80g – almost certain death?