The even better point is that code officials should not let firefighters dictate building science. They don’t know what they’re talking about.
Push The Needle
The core, real question re: single stair buildings to rank and file firefighters should be this:
Which of these 2 buildings would you prefer in an active fire? Which is more likely to reach a point where you need to call in more help, delaying full response and increasing risk for anyone inside?
Jason Cox
How many units in this top example sit on the “wrong side” of the two stairs at each end, meaning they would be trapped if that stairway was compromised? You’ll count 6 each.
Meanwhile single stair buildings have little to no corridor. (See the small building example at bottom).