Electroluminescence

In the context of essential (fire) safety systems and equipment, electroluminescence is the underlying technology used to provide visual status and emergency guidance. It is primarily found in:

• Indicators & Annunciators: Light Emitting Diodes (LEDs) are the most common application of electroluminescence. They are used on Fire Alarm Control Panels (FACPs) and mimic panels to provide "Alarm," "Fault," and "Disable" (Isolate) status notifications.
• Visual Alarm Devices (VADs): VADs utilize high-intensity Light Emitting Diodes (LEDs) to provide a pulsing or flashing light during a fire alarm. They are essential for alerting occupants who are deaf or hard of hearing, or for use in high-noise environments where audible alarms may be ineffective.
• Emergency Exit Signs: Electroluminescent panels (often thin-film) or LED-driven signs provide the required luminance to ensure exit paths are visible during a power failure.  
• LCD Backlighting: Liquid Crystal Displays (LCDs) used for text-based fire panel interfaces do not emit light themselves; they rely on an electroluminescent backlight (typically LED) to remain readable in low-light conditions.

• LED (Light Emitting Diode): A semiconductor light source that is the modern standard for fire alarm indicators due to its long life, low power consumption, and high reliability.
• Thin-Film Electroluminescent (TFEL): A technology used in some specialized "glow" panels or older backlit displays, known for providing very even light distribution across a flat surface.
• Contrast with Photoluminescence: Unlike photoluminescent signs (which "charge" using ambient light and fade over time), electroluminescent devices require an active power source (mains or battery) to produce light.

The reliability of electroluminescent components is necessary for life safety, as such maintenance is required by Australian Standards:

• AS 1851 (Routine service of fire protection systems and equipment)
  • Requires the regular inspection of control and indicating equipment (c.i.e.) visual indicators such as LED indicators and liquid crystal display backlights are functional. A "Lamp Test" is typically performed to verify that every electroluminescent indicator can still successfully signal an emergency state.
  • Yearly test to confirm the operation of each visual alarm devices (VAD) is working, that may include electroluminescent components.
• AS 2293.2 (Emergency light and exit sign systems maintenance)
  • This standard dictates the testing of exit signs and emergency lights. Because these devices rely on electroluminescence to guide occupants, they must undergo:
    • 6-Monthly Discharge Test: Ensuring the battery can power the electroluminescent source for the required duration (usually 90 minutes). 
    • Yearly Inspection: To ensure the light output (measured in candelas or lux) is not obscured by dust or degradation of the EL material.