These are put in while in the HVAC ductwork and therefore are activated to close whenever they feeling smoke. Smoke dampers are frequently made from aluminum and have a motorized actuator that closes the damper. بطاقة العربية للطيران بلاتينوم الائتمانية تذكرتك لمزيد من السفر Prevent undesired airflow and manage process https://erickcqfsf.nizarblog.com/36823271/air-control-dampers-for-hot-climates-things-to-know-before-you-buy