Type B curtain dampers are commonly used when duct height is what measurement or less?

Type B curtain dampers are specifically designed for use in low-profile duct systems, which is closely linked to their operational characteristics. They are approved for applications where the duct height is limited, typically at or below 12 inches. This is due to the need for the damper design to effectively control airflow in confined spaces without causing excessive resistance or pressure drop, which might occur in ducts that are significantly taller.

Using Type B curtain dampers in ducts taller than this height can result in inefficiency or mechanical failure, as these dampers may not provide the optimal sealing and operational capabilities required for larger ducts. Therefore, recognizing that Type B dampers are suitable for ducts 12 inches in height or less allows HVAC professionals to apply the correct equipment in the right scenarios, ensuring both compliance with standards and the effectiveness of the overall HVAC system.