AC can be provided to all rooms or just selected rooms.
The number of rooms to be air conditioned, and subsequent internal and external thermal loads, determines the capacity of the air conditioning system.
Day Night AC System
In warmer states, there is often a perception that the air conditioning system must be able to cool all rooms at the same time. Subject to undertaking computerised heat loads, for a given location and orientation of rooms, this can result in an AC system in the order of 1.7 times larger than a day night air AC system.
A day/night AC system sizes the AC system for the largest cooling load of either the day zone or the night zone (not both). Typical day zones are; kitchen and living areas. Typical night zones are bedrooms.
The AC system is typically sized on the peak design temperature day at peak solar loads. For a large proportion of the year these loads do not occur, thus the AC system sized for the day zone can ofton handle cooling or heating of all rooms. Basically you are not oversizing the AC system for a small number of days each year.
There is no requirement under the NCC to provide air conditioning to corridoors. Indeed there is no NCC requirement to supply outdoor air to residential corridors.
Outside air may be required if the corridor is utilised as make up air path for apartment exhaust systems (door under cuts [non preferred] of tansfer air ducts between corridor and apartent]. Another situation is where corridors are provided with ventilated (exhausted) garbage rooms (these will require make up air).
In luxuary aparments air conditioned air and or tempered outdoor is ofton supplyed to the corridoors.
The NCC (not rquiring fresh air to residential corridors) is contrary to to the design guidelines in SEPP 65 (applies in NSW), which treat corridors as active spaces requiring ammenity (light and air).
The author is of the opinion corridors should be provided with a minimum of 1 l/s/m2 or opearble façade openings at 5% of the corridor floor area.