At Home - Bill Bryson [167]
“Perspective of a staircase” by Thomas Malton (photo credit 14.1)
Everybody trips on stairs at some time or other. It has been calculated that you are likely to miss a step once in every 2,222 occasions you use stairs, suffer a minor accident once in every 63,000 uses, suffer a painful accident once in every 734,000, and need hospital attention once every 3,616,667 uses.
Eighty-four percent of people who die in stair falls at home are sixty-five or older. This is not so much because the elderly are more careless on stairs, but just because they don’t get up so well afterward. Children, happily, only very rarely die in falls on stairs, though households with young children in them have by far the highest rates of injuries, partly because of high levels of stair usage and partly because of the startling things children leave on steps. Unmarried people are more likely to fall than married people, and previously married people fall more than both of those. People in good shape fall more often than people in bad shape, largely because they do a lot more bounding and don’t descend as carefully and with as many rest stops as the tubby or infirm.
The best indicator of personal risk is whether you have fallen much before. Accident proneness is a slightly controversial area among stair-injury epidemiologists, but it does seem to be a reality. About four persons in ten injured in a stair fall have been injured in a stair fall before.
People fall in different ways in different countries. Someone in Japan, for instance, is far more likely to be hurt in a stair fall in an office, department store, or railway station than is anyone in the United States. This is not because the Japanese are more reckless stair users, but simply because Americans don’t much use stairs in public environments. They rely on the ease and safety of elevators and escalators. American stair injuries overwhelmingly happen in the home—almost the only place where many Americans submit themselves to regular stair use. For the same reason, women are far more likely to fall down stairs than men: they use stairs more, especially at home, where falls most commonly occur.
When we fall on stairs, we tend to blame ourselves and generally attribute the fall to carelessness or inattentiveness. In fact, design substantially influences the likelihood of whether you will fall, and how hurt you will feel when you have stopped bouncing. Poor lighting, absence of handrails, confusing patterns on the treads, risers that are unusually high or low, treads that are unusually wide or narrow, and landings that interrupt the rhythm of ascent or descent are the principal design faults that lead to accidents.
According to Templer, stair safety is not one problem but two: “avoiding the circumstances that cause accidents and designing stairs that will minimize injuries if an accident occurs.” He notes how at one New York City railroad station (he doesn’t say which) the stair edges had been given a nonslip covering with a pattern that made it difficult to discern the stair edge. In six weeks, more than fourteen hundred people—a truly astonishing number—fell down these stairs, at which point the problem was fixed.
Stairs incorporate three pieces of geometry: rise, going, and pitch. The rise is the height between steps, the going is the step itself (technically, the distance between the leading edges, or nosings, of two successive steps measured horizontally), and the pitch is the overall steepness of the stairway. Humans have a fairly narrow tolerance for differing pitches. Anything more than 45 degrees is uncomfortably taxing to walk up, and anything less than 27 degrees is tediously slow. It is surprisingly hard to walk on steps that don’t have much pitch, so our zone of comfort is a small one. An inescapable problem with stairs is that they have to convey people safely in both directions, whereas the mechanics of locomotion require different postures