Supply Air (Make-up Air) Systems (S/A) are designed to bring fresh air into your apartment to replace the humid or polluted air being extracted via exhaust systems.
Make-up Air needs to be clean and not add a further contaminate load to the enclosure. Outdoor airflow rates may need to be increased to enclosures to ensure an appropriate balance of make-up to exhaust. The standard states that make-up air cannot be taken from an enclosure served by a required exhaust ventilation system (this includes a mechanically ventilated car park, commercial kitchen, swimming pool, etc.).
The Building Code of Australia (BCA) enforces Australian Standard AS 1668.2-2012, requiring make-up air to enter an apartment at a flow rate of no less than 75% and no more than 90% of the exhaust airflow rate.