The Normally Closed (NC) auxiliary contact is a mirror contact to the main contacts and is mechanically linked to the Normally Open (NO) auxiliary contacts.
Testing and maintenance requirements are provided in Chapter 19 of NFPA 80 for fire dampers and Chapter 7 of NFPA 105 for motorized smoke dampers and combination fire/smoke dampers.
Continuous airflow measurements during anesthesia monitoring, intensive care treatment, and in clinical and ambulatory environments provide important information for the assessment of cardiorespiratory and breathing circuit behavior.