HVAC Journeyman Practice Exam

Factory-made air ducts are typically prohibited from serving more than one story due to safety and design considerations. These ducts are designed and manufactured to specific standards, often intended for particular types of installations, and when applied to multi-story systems, they may not adequately address the complexities involved, such as air travel distance, pressure differentials, and potential airflow issues.

Using factory-made air ducts in multi-story applications can lead to challenges in achieving even air distribution and maintaining temperature control across different floors. Additionally, proper fire safety measures need to be adhered to in multi-story applications, and many factory-made ducts may not have the necessary certifications or fire ratings required for such uses.

In contrast, other types of ducts, such as flexible ducts, metal ducts, and spiral duct systems, can often be adapted for multi-story applications given their design flexibility or specific construction materials that can meet safety standards for various building configurations.