G'day welcome back to Buildsum in this video what I want to show you is how we calculate the number of steps and
How wide they are to get up to a platform like this one so
This platform is 1600mm high or 1.6m
So the first formula you need is we take the rise of the flight which is
1600 we divide that by the average allowable rise of a step
so if you look at the National Construction Code
Here in Australia we have this table
It tells us that for a rise or riser
The maximum rise is 190 and the minimum rise is 115, so you can add those together,divide by 2
you'll get
150 - I think off the top of my head, but we'll work with 150mm
So our average rise is 150mm
so if we divide our 1600 by
150 we get 10.666
Now if I plot that out on here
You'll see that the feature one of these is 150, mil
We actually end up with an uneven step at the top. Okay, so the distance from here to here
It's obviously not the same as the distance from here to here or here to here so
again according to the National Construction Code, we can't
have an uneven step in their flight, so that's not going to work so what we do
and of course we know we're close we can either round this up or down doesn't really matter but for reasons of efficiency
the less timber we have in the stairs are more economical, so we'll say we're going to have 10
i'll round that down to 10
So 10 that rises in our flight, so if we now divide our 1600 by 10
We get 160 so
10 rises of 160mm each so 10
Yeah, so all even so that's going to work with the code
So that's how we work out that rises, so now we need to look at it going so we've got 10 Rises
We've got to have 9 Goings
always one less
Okay
so we're taking 9 goings and
We times that by the average going for a step, so if we go back to our table
You see over here on a going side. We have a maximum going of 355 a
Minimum going of 240 and the average again of that roughly, I think it works out about 297
So we'll just say 300 is our average going
So come back here knowing goings
average of 300 so it gives us a
Going of our flight of 2700 so that's the distance from the front of the first step
to the
front of the landing or the back of the last step
That's that going if that becomes our going of our flight
Now we need to make sure it works
So it should work in this case, but it's good get used to it, so easy going check is two Rises
plus are going (2R+G)
and they have to fall within our slope relationship, so they need to land somewhere between
700 and
550 so
160 plus 160
plus 300 gives us
620
So obviously that becomes between those two figures
So that should mean that this is be a comfortable set of stairs to walk up and they comply with the National Construction Code
So there you go, that's how you work out the Rises and goings for an unrestricted
staircase