At what height do falls become deadly?
According to the World Health Organization, falls are the one of the leading cause of traumatic death in the world (second only to traffic accidents), accounting for more than 646,000 fatalities each year.
We have a saying in the safety world: "It's not the fall that kills you; it's the sudden stop at the end of it." That might sound a bit silly, it is true. We can safely travel at a much greater accelerations than the ones we're subjected to in a workplace fall. Just think about flying, parachuting, and bungee jumping – they all send us falling just as fast but no injury comes of them as long as we decelerate slowly.
So, does that mean that the height doesn't make much of a difference? No. It's true that it's the impact that causes injury or fatality. But since higher falls have greater impact, they also have a higher potential for injury or death.
Breaking Down the Stats
The fatality statistics vary from year to year, but there seems to be a significant fatality rate increase after the 10-foot threshold. The Center for Construction Research (2018) states that:
- 11.7% of fall-related fatalities resulted from falls from heights between 6 and 10 feet
- 19.7% from falls 11 to 15 feet
- 17.4% from falls 16 to 20 feet
After that, the numbers start to decrease. But that doesn't mean that workers are more likely to survive a fall from a greater height. What probably accounts for the distribution is that work at height is typically done at elevations between 10 and 20 feet. So, naturally, that's where the greater proportion of fatalities occur.
Heights over 30 feet also account for a large percentage of fall fatalities (19.6%), but this is very likely due to the fact that the researchers bundled all fatalities over 30 feet into a single group rather than continuing with their 5-foot gradation.
Moreover, since the researchers have determined only the percentage of fatalities for each height but did not record how many falls from the same heights have not resulted in a fatality it is difficult to say whether any particular height is deadlier than another.
Other trauma studies seem to indicate that a fall from a 4th floor (about 48 feet) has a 50% survival rate, while a fall from a 7th floor (about 84 feet) has only a 10% survival rate. These studies put a numerical value on a fact we have discussed at the beginning of this answer: the severity of an injury and probability of death increases with height.
Considerations Beyond Height
While it's generally true that the longer the fall, the higher the probability that it will be fatal, there are also other variables that can dictate the outcome. These include:
- Surface – For the same height, tilled soil and snow have a lower fatality rate than concrete. Landing on a rebar from 6 feet could also be way more dangerous than falling 20 feet onto a flat surface.
- Age – The age group most likely to die in the event of a fall are those 65 and over, followed by those who are under 15, and then people aged 15 to 24.
- Gender – This one is a bit contentious. While there is some evidence to suggest that men are more likely to die in a fall than women, it might be due to the fact that they are over-represented in high-risk jobs.
- Luck – There are countless cases of people who have fallen from extreme heights (well over 100 feet in some cases) and have not only survived, but sustained only minor injuries. Unfortunately, most people who experience falls from such heights are not so lucky.
Fall protection is required for anyone who is at risk of falling from more than 10 feet. That's the height at which falls become noticeably more dangerous. However, as the Center for Construction Research's data shows, falls from a shorter elevation can still be fatal. So, make sure fall protection is in place in any situation where there is a risk of injury, even if workers are only working at six of seven feet.
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