Friday, January 31, 2014

A Head for Stairs

The building in which I spend at least half of my waking hours was built in 1850. Normally, I’m the only occupant in the office unit. (There is residential unit with a mirror image floor plan on the other side of the building.) After 40 years of familiarity with the structure, I instinctively take into account its peculiarities. I know that the treads on the stairs to the basement are narrow, and place my feet accordingly; I know just how low the joists are in the basement and duck the appropriate amount without looking. I know that the hinged trap door to the attic is absurdly heavy and needs to be secured firmly in the open position before risking letting go of it. I know which steam radiators to turn on and which to leave off in order to balance the heat in the winter.

None of these will trouble visitors, of course, but there is one peculiarity about which I always warn them: the head room on the stairway to the second floor. The stairs themselves are conventional, but the point at which they pass under the second floor is not as high as on modern buildings, presenting a possible head-knocker. Going up seems not to be a problem for anyone, but coming down can be a painful surprise to people of my height or taller. A little more than half the time I can descend the stairs with head held high and get away with it, but, if there is any extra bounce to my step, thwack! It didn’t take too many repeats of being brought to my knees before cocking my head to left or right on the stairwell became completely unconscious; this buys just enough distance to keep me headache free.

Stairs are dangerous enough as it is, especially when descending. The second most common cause of accidental death, exceeded only by car accidents, is falling down stairs. The most stairs I ever tackled at one go were the 897 steps (with 50 landings) in the Washington Monument. I descended, not ascended. One no longer is allowed to do either. While security is cited as a reason, safety probably is a consideration too. Imagine the poor paramedics having to stretcher an injured visitor stranded half-way up the stairway.

Insurance actuaries have calculated the risks with their usual precision. You will miss a step once every 2,222 times you use stairs. This can result in anything from that jarring but harmless thud we’ve all experienced to a full tumble. You will suffer pain once every 63,000 uses, modest injury once every 734,000 uses, and hospitalization once every 3,516,667 uses. This sounds like a pretty small hazard until one considers how many stairs we encounter just on an average day. For some reason, the highest risk is on stairways with four or fewer steps. Overconfidence perhaps. Some people are especially inept at navigating stairs. It is not clear why, but 40% of injuries on stairs are suffered by people who were injured on stairs before. Fit people are actually more at risk than unhealthy people, probably (once again) through overconfidence. Stairways steeper than 45 degrees or shallower than 27 degrees give the most trouble. US building codes for new construction require risers of no more than 7 inches (17.78cm) or less than 4, and treads (goings) of no less than 11 inches (27.94cm) – which is a maximum of about 32 degrees.

Stairs are such an obvious solution to accessing a different elevation comfortably that they appeared independently everywhere ancient peoples ever built on multiple levels. The oldest surviving example, thanks to the durability of stone, is 9000 years old at Jericho. The oldest wooden staircase still in existence, improbably enough, is in a Bronze Age salt mine in Hallstatt, Austria. It is safe to say stairs aren’t going away anytime soon. But, while navigating them, remember to look up as well as down at one’s feet. Why? This blog was prompted because I was distracted while reading a letter as I descended my office stairs yesterday, and, for the first time in many years, neglected to cock my head.

Stairs uncovered at Jericho 


  1. The most stairs I've tackled was a climb to the whispering gallery in St. Paul's Cathedral in London. I don't remember how many steps, but it was on those old twisting narrow medieval style staircases. Very dangerous indeed. But everyone was moving pretty slowly up and down them, so that was good.

    I believe that folks get hurt more often on fewer number of stairs. As a kid, i would always try to jump down the last few stairs. One day I landed on a rug that slid out from under me and I fell on my ass. and knocked my head agains the bannister. I never jumped down a staircase again... at least not if there was a rug at the bottom.

    I wonder if there are stats for the number of times a cat has crossed in front of someone while they are on the stairs and that causes the tumble. Both of my cats do that on a regular basis. They want to add some thrills to my mundane life. ;)

  2. I didn't find numbers specifically for cats and steps, but I did find CDC report that 87,000 Americans are sent to ERs each year from falls associated with pets: "66.4% of falls associated with cats and 31.3% associated with dogs are caused by falling or tripping over the animal."

    Thrills indeed.