h wrote:
....

Why would you need a second exit for an upstairs of less than 500 sq. ft.?

All sleeping spaces are required to have two exits regardless of size;
if there's not a large-enough window in the attic, the second stairway
is the result.

Now, whether it would have any real effect in case of fire given the
size of the structure is another question but Code doesn't ask such
questions nor do most inspectors/departments when approving plans.
Unfortunately, it's generally a checklist sorta' thing--"No egress
window, one staircase? Well, you'll have to add another stairway." If
it were such that there's a door on two sides of the upstairs room at or
near the head of each, it _might_ even make a difference.

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