• Initiating Device  A system component  that originates transmission of a change  of state condition, such as a smoke  detector, manual fire alarm box, supervisory switch
  • Initiating Device Circuit (IDC) A circuit to which automatic or manual initiating devices are connected where the signal received does not identify the individual device operated.
Manual vs Automatic
  • There are many types of initiating devices All of them can be classified as either manual or automatic.
  • The most common manual initiating device is the fire alarm box, ( pull station)
  • Automatic initiating devices include( heat detectors, smoke detectors, gas detectors.
  • These initiating devices are designed to automatically sense some type of environmental condition and to automatically signal the control unit.
Spot vs Line

Initiating devices. such as smoke detectors and heat detectors. can be categorized as being either a spot type or a line type. Line type detectors will be covered later in this course.

Restorable vs Non-restorable

Conventional VS Addressable
  • Regardless of whether an initiating device operates manually or automatically it can be classified as being either conventional or addressable. Conventional initiating devices operate like switches. They are either off, which is normal, or they are activated.
  • With conventional initiating devices, the fire alarm control unit does not know which device is on. The panel can only tell that some initiating device on a particular circuit has been activated.
  • Addressable initiating devices have two-way communication with the fire alarm control unit. This allows them to communicate their status to the fire alarm control unit and convey exactly which device has been turned on.