A duct system is a network of passages, typically constructed from metal, plastic, or specialized materials, designed to transport air or other gases within a controlled environment. It plays a critical role in heating, ventilation, air conditioning (HVAC), and cleanroom systems by distributing conditioned air, removing contaminants, and maintaining airflow balance.

In pharmaceutical and cleanroom environments, duct systems are engineered with precision to ensure sterile air circulation, support temperature and humidity control, and minimize particulate contamination. They are often integrated with HEPA (High-Efficiency Particulate Air) or ULPA (Ultra-Low Penetration Air) filters, ensuring compliance with strict regulatory standards like GMP (Good Manufacturing Practices) or ISO classifications.