Intent 1:
To exempt certain doors from the application of Sentence (1), where
- a vestibule is not justifiable for reasons of function,
- the door is rarely used as a service or emergency exit
door,
- the door is only used seasonally,
- the size of the space the door serves is sufficiently
small such that the vestibule would occupy an unacceptably large part
of the usable space, or
- the building is in a warmer climate zone, and as such,
a vestibule would result in minimal energy gains and is therefore
not justifiable, and the building is small to mid-size making the
installation of a vestibule uneconomical.