What is the minimum size of a ventilation hole for residential structures according to basic practice 16?

The minimum size of a ventilation hole for residential structures, as outlined in basic practice 16, is 4 feet by 4 feet. This size is considered effective for ensuring proper airflow and smoke evacuation during firefighting operations. Adequate ventilation is critical in reducing heat and smoke conditions within a structure, allowing firefighters to operate more safely and effectively. The 4'X4' size strikes a balance between being sufficiently large for airflow while remaining manageable for firefighters to create, especially in residential settings where structural integrity and access can be challenging.

Larger sizes, while they could provide increased airflow, may not be necessary in many residential scenarios and could complicate the task of creating the hole efficiently and safely. The guidelines aim to standardize practices for effectiveness without overcomplicating operations, especially under the stress of emergency situations.