When procuring fire dampers, the most critical technical factor is the Fire Resistance Rating, typically ranging from 1.5 to 3 hours. You must ensure the blade material is high-grade galvanized steel or stainless steel to prevent corrosion. Additionally, verify the fusible link temperature setting (commonly 70°C or 165°F), which triggers the automatic closure. For motorized versions, check the actuator voltage compatibility (e.g., 24V or 220V) and torque capacity to ensure it can handle the duct's air pressure.