Analysis of Temperature Distribution in Underground Parking Lots of Apartment Complexes : Focused on Identifying Potential Pipe Freezing Zones

Purpose: This study aims to identify freeze-prone areas in underground parking lots of apartment complexes during winter to inform design guidelines for the application of wet sprinkler systems. While wet sprinklers are effective for early fire suppression, they are vulnerable to freezing and often require costly antifreeze measures in cold climates. Method: A total of 149 apartment complexes in Sejong City, South Korea, were surveyed and categorized based on the configuration of exterior openings into three types: ramp, pilotis, and deck. One representative complex from each type was selected for wintertime temperature monitoring. Indoor temperatures were recorded every 10 minutes for up to 22 days using a grid method with 10-meter intervals from the openings. The lowest temperature recorded in each parking lot was used to evaluate worst-case freezing conditions. Result: The ramp-type parking lot maintained indoor temperatures above 0℃ even when outdoor temperatures dropped below 9.7℃, indicating a low risk of freezing. In contrast, the pilotis and deck types showed significant cold air inflow, with over 40% of the deck-type area experiencing sub-zero temperatures. However, basement level 2 remained above freezing in all cases. These results suggest that ramp-type structures are most suitable for wet sprinkler systems, while pilotis and deck types may require additional antifreeze measures or design modifications.