Greetings!

I'm in the process of getting estimates for replacement windows (in Georgia) and I'm getting some differing opinions on whether or not some windows need to have tempered glass. I found the 2006 IRC Code -Selected Tempered Glass Requirements but need a little help interpreting some of it.

2. a 24"x48" window at the top of the stairs, 32" from the floor, on the same wall the stairs are on
   
   #10 in the code says "Glazing adjacent to stairways, landing and ramps within 36" horizontally of a walking surface when the exposed surface of the glass is less than 60" above the plane of the adjacent walking surface."
   
   Based on that, I think it needs to have tempered glass...is that correct? temper just the bottom sash or both sashes?

3. 36"x72" windows, about 8" from the floor, in the living room and kitchen
   
   #7 in the code says "...that meets ALL of the following: 7.1. Exposed area of an individual pane is greater than 9 square feet. 7.2. Bottom edge is less than 18" above the floor. 7.3. Top edge greater than 36" above the floor. 7.4. One or more walking surfaces within 36" horizontally of the glazing."
   
   I get the less than 18 and more than 36 items, but I'm not 100% clear on the other two. Is the 9 square feet for the entire window or each sash? Walking surfaces...is that interior such as the floors in the rooms, or exterior like sidewalks?

4. For the two items above, is there such a thing as being grandfathered in because this isn't a new construction?

I don't have kids or pets (or wild parties) :-) so I'm not too worried about anything happening, but I do want to do this correct and to code.

Many thanks in advance!