Second floor walkways

Here is the code section that triggers the treatment of second floor walkways as corridors:

 

SECTION 1019

EGRESS BALCONIES

1019.1 General. Balconies used for egress purposes shall conform

to the same requirements as corridors for width, headroom,

dead ends and projections.

1019.2 Wall separation. Exterior egress balconies shall be

separated from the interior of the building by walls and opening

protectives as required for corridors.

Exception: Separation is not required where the exterior

egress balcony is served by at least two stairs and a dead-end

travel condition does not require travel past an unprotected

opening to reach a stair.

It looks like the 10 feet requirement comes from the accessible means of egress section:

1007.7 Exterior area for assisted rescue. The exterior area for

assisted rescue must be open to the outside air and meet the

requirements of Section 1007.6.1. Separation walls shall comply

with the requirements of Section 705 for exterior walls.

Where walls or openings are between the area for assisted rescue

and the interior of the building, the building exterior walls

within 10 feet (3048 mm) horizontally of a n,onrated wall or

unprotected opening shall have afire-resistance rating of not

less than ,1 hour. Openings within such exterior walls shall be

protected by opening protectives having a fire protection rating

of not less than 3/4 hour. This construction shall extend vertically

from the ground to a point 10 feet (3048 mm) above the

floor level of the area for assisted rescue or to the roof line,

whichever is lower.