27 Oct 2009 17:55 UTCTue 27 Oct 2009 - 5:55 pm UTC
I would like to know what is a "normal" stair and if it varies in different parts of the world. To me 6.75" high with a 12" tread is fairly normal. My father used to say "for a stair to ~feel~ right, twice the rise plus the run should be under 24 inches" and I would like to know if there are other rules of thumb such as that.
I would the like the answerer to define the terms of reference to some extent but I need to have some idea what the bell-curve is for so-called "normal" stair dimensions (i.e, weather a 5, 6, 7, or 8 inch rise is the majority)
If "normal" varies from country to country or if it does over different periods of history that info would be a plus.
27 Oct 2009 18:28 UTCTue 27 Oct 2009 - 6:28 pm UTC
Your question is either an easy one to answer, or incredibly difficult...I'm not sure.
In terms of building standards, home construction has been moving towards international standards for some time now. Standards for stairway construction are given a nice visual presenation in this document:
Visual Interpretation Of The International Residential Code -- Stair Building
The rise and run of an acceptable stair is clearly laid out. So...if that's the answer you're looking for, then this was, in fact, relatively easy.
However, if you're truly looking for bell curves on stair construction throughout history, and in different countries, then that's a lot more complex, and may not even be readily answerable. Before I go down that path, though, I wanted to check with you to clarify just what type of information you're seeking.
Let me know if the international standards information is what you needed, of if there's something more I can do for you on this.
27 Oct 2009 18:32 UTCTue 27 Oct 2009 - 6:32 pm UTC
I'm interested in what's actually out there. National (or int'l) standards would be part of the 'stair picture'.
28 Oct 2009 15:34 UTCWed 28 Oct 2009 - 3:34 pm UTC
From what I can see, there isn't very much in the literature on typical real-world stair dimensions. Most of what exists stems from analyses of accidents.
There is a pretty good overview of current literature and the history of stair design in this paper:
Parametric design of stairs
especially in Section 2 of the paper.
Also be sure to see the numerous comments (above) made here by mathtalk and others, as there's some interesting observations to be had.
28 Oct 2009 16:44 UTCWed 28 Oct 2009 - 4:44 pm UTC
And just for kicks, some REALLY steep stairs:
28 Oct 2009 19:17 UTCWed 28 Oct 2009 - 7:17 pm UTC
I was hoping there was some kind of social research that talked about stairs from some kind of objective view of what existed. I'll wait a few more days to see if someone keys in on that in particular but otherwise I can (reasonably safely) conclude that: 1) stairs are pretty much the same the world over and 2) for a few hundred years there has been some suggestion that two times the rise plus the run of a stair should be approximately the length of a normal walking pace (presumably for an average person).
If that's the case, and 7 inches seems to be in the vicinity of a "normal" rise, then the demographics related to average height should produce an approximate of the average stride length and that gets me back to where I want to be.
The destination of this information is the design of a device that an be fine-tuned to work better in places where the average step differs from North American code by more than three quarters of an inch, but would still work if the variance was as much as an inch more than that. What I want to know is how adjustable, if at all, should I make the device in the first place. If the answer is "not at all" I expect more efficient production when that stage comes.
I'll wait a few more days and if nothing pops up I call this one solved. I am pleased with the input so far.
31 Oct 2009 17:32 UTCSat 31 Oct 2009 - 5:32 pm UTC
Ok, where's the "pay" button? How do I pay this and close it... All I see is "clarify" "cancel" and "add comment" at the bottom and pretty much the same thing at the top?
Why can't software be written with a little intuitiveness once in a while!
Seriously, I don't see, on the current page, a place to close this question, unless I want to cancel it and not pay. Why?! I'm guessing the answer is that I have to navigate to another part of this web site and on principle I think I shouldn't have to. Every comment by every question answerer should have a "pay this answer" button so that I can pay two or three different answers if I like them. If "pay this answer" is not acceptable, surely a "tip this guy" would make sense.
31 Oct 2009 18:41 UTCSat 31 Oct 2009 - 6:41 pm UTC
I'm glad you got the information you needed here.
But actually, Uclue isn't designed with a pay button because payment happens automatically once a formal answer is posted (as I'm doing now) rather than a series of clarifications.
Thanks again for an unexpectedly interesting topic.
1 Nov 2009 02:03 UTCSun 1 Nov 2009 - 2:03 am UTC
I looked for specs on airline stairs, but the information is surprisingly elusive. The guidance and specifications are contained in these industry standards:
General Requirements for Aerospace Ground Support Equipment Motorized and Nonmotorized
but do not appear to be available short of purchasing the standards themselves.
Hope that's a bit of a help, though.