Hardness of floors

[Brennan]

I am a doctor in the Children's Hospital in Manchester, United Kingdom. Among other things, I deal with children who injure themselves falling from heights on to indoor floors. Parents, lawyers and other doctors often ask me whether injuries are more likely when children fall onto hard floors such as concrete rather than softer ones such as carpeted floors. I am trying to find someone who knows how to measure the hardness of floors. Can anyone help me? Brennan

[Bob Morrison]

Common sense will tell you that someone falling onto a concrete floor will more likely sustain an impact injury that some falling onto a heavily carpeted floor.

If you insist on having test data, then I think that a local testing laboratory might be able to devise some sort of impact test. Or you could devise you own test. Perhaps you could use hard boiled eggs dropped from various heights onto various surface types. Of course, the eggs will crack differently depending on whether or not they impact on the side or on the ends. Eggs are stronger when dropped on their ends.

Obviously with children, the damage inflicted in a fall will depend on how they land as well. Land on their bottom and almost no damage -- land on their head and there is potential for serious damage.

[dpb]

As Bob Morrison points out, the actual hardness of the floor is only one variable, and probably not the most significant one at that in the severity of injury.

It is not at all difficult to ascertain the actual hardness of a flooring material itself such as wood, tile or concrete. That measurement, however, isn't feasible for soft or resilient materials such as carpet or even the cushioned vinyls, say.

What is really significant is more nearly described as the elasticity, but again as Bob points out, it only is common sense that a poured concrete floor has the ability to impart more damage for a specific fall height, attitude, etc., than a carpeted one.

I really see little point in the question other than the obvious one -- litigation. Can you explain in more detail what your end result of the question is intended to be? That might provide futher insight on how one might investigate the issue. I would think the best data, however, would be empirical observation of reported accidents supported by decent forensic examination of the accident site and reconstruction of the accident itself to generate the parameters thereof. I would be surprised if the medical literature doesn't have at least something along these lines already.

[bowgus]

Hardness is not the term you should be focussing on. Hardness typically refers to the ability to resist scratching (e.g. diamond harder than glass). You might look instead into shock absorption - flooring. Or how about keep it simple. Drop a basketball onto different surfaces ... concrete, carpet with underpad, ... or ... "this is your head on concrete, this is your head on carpet." ... and leave it at that :-)

[CWatters]

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