Perforated tiles should be located in front of equipment racks, aligned with cold aisles, to deliver supply air directly to server intakes. Best practice is one perforated tile per rack, adjusted based on airflow requirements and rack load.
* Placing tiles at the back (A) disrupts airflow.
* Spacing every 5th rack (B) provides insufficient cooling.
* Placing near AC (D) causes uneven distribution and pressure loss.
Thus, option C is correct.
References: ASHRAE TC 9.9 "Airflow Management," ANSI/TIA-942-B §6.5.