If you follow the definitions within either building or fire code for “exit”, “means of egress” and “access to exit” you should come to the conclusion that exterior stairs cannot be considered as an “exit stairway” (Exit’s are part of a means of egress which is a continuous path of travel from any point in a building).
If the fire escape (exterior stairs) is serving as a required exit then sentence 126.96.36.199. (1) applies.
Even if you wanted to look at it as an exit stairway, then Sentence 188.8.131.52.(1) would require it be protected by a 30 or 45 minute fire resistance rating depending upon building height.
I’m not sure why you refer to the building as Type 3, in Ontario we have combustible, non-combustible and heavy timber. Sounds to me like you are dealing with a combustible building. You would have to have the owner get a qualified designer to specify the fire resistance rating of the exterior wall assembly to confirm it met the 30 or 45 minute fire resistance rating, and then of course there are the requirements for protection of openings in fire separations. Likely less expensive for the owner to protect window and door openings adjacent the fire escape.
The building code doesn’t allow fire escapes to be constructed on “new buildings”, however the building code does allow exterior stairs provided they are not a required exit, or in some cases where the dwelling unit has a second and separate means of egress.
Hope this helps.