Simulate real-world alarm activations, trouble conditions, and supervisory signals. Click any zone to trigger or clear events.
This interactive simulator lets engineers and technicians trigger alarm, trouble, supervisory, and silenced conditions on individual zones to practice fire alarm system response and operator acknowledgment procedures. It is built around real FACP signal categories as defined by NFPA 72 and is used for training, system testing planning, and acceptance test preparation.
NFPA 72 Chapter 23 defines four primary signal types that a fire alarm control panel must distinguish and annunciate separately. Alarm signals indicate an active fire event from an initiating device (detector, pull station, flow switch). Trouble signals indicate a system fault — an open circuit, ground fault, or failed device — that impairs the system's ability to detect or notify. Supervisory signals indicate an off-normal condition in a fire protection system component, such as a closed sprinkler valve or low air pressure in a dry system.
Temporary silencing (acknowledgment) clears the audible notification at the panel but leaves visual indicators active until the system is reset. Per NFPA 72 §23.8.7, a system reset requires the initiating condition to be cleared — a latched alarm cannot be reset while the activating detector still reads above its alarm threshold.
NFPA 72 Chapter 23 (Protected Premises Fire Alarm Systems) governs signal classification, annunciation, acknowledgment, and reset requirements. NFPA 72 §23.8.3 requires that trouble signals be annunciated at the FACP within 200 seconds of a fault condition. NFPA 72 §18.4.2.1 mandates temporal-3 coding (0.5 s on / 0.5 s off / 0.5 s on / 0.5 s off / 0.5 s on / 1.5 s off) as the standard evacuation audible signal. IFC (International Fire Code) Section 907 and local AHJ requirements govern acceptance testing procedures that must confirm each signal type operates correctly.
Multi-zone systems must be carefully mapped to ensure that supervisory zones (sprinkler valve tampers, pressure switches) are configured as non-silenceable and non-resettable until the off-normal condition is corrected, per NFPA 72 §23.8.1.3. Cross-zone alarm verification, where two separate zones must activate before full alarm, is used in special suppression systems to prevent accidental suppression agent discharge.
Annunciator placement and signal priority must be designed to ensure responding fire department personnel can immediately identify alarm floor and zone from the fire command station. NFPA 72 §27.6 requires the annunciator to display the zone in alarm, the type of signal, and whether the system has been silenced or acknowledged. For voice evacuation systems, the FACP must be capable of generating and broadcasting pre-recorded or live voice messages to specific zones or all zones simultaneously.
Select a building type to load the appropriate zone configuration. Click any zone card to trigger an alarm, trouble, or supervisory condition, or click Reset to return that zone to normal. Use the Run Auto Scenario button to watch a scripted sequence of events play out automatically, including alarm escalation, silencing, and reset. The event log on the right records every action with a timestamp. Use the Reset All button to clear all conditions and return the system to normal before starting a new scenario.
Temporal pattern 3 consists of three 0.5-second pulses separated by 0.5-second pauses, followed by a 1.5-second silence, repeating continuously. NFPA 72 §18.4.2.1 and ANSI S3.41 standardized this pattern as the universal fire evacuation signal in the US so that building occupants recognize the same sound in any building type, regardless of the horn or strobe manufacturer.
A trouble signal indicates a system impairment — the fire alarm system itself has a fault (wiring open, ground fault, device failure) that may prevent it from detecting or reporting a fire. A supervisory signal indicates that a passive fire protection system component is in an off-normal state (e.g., a sprinkler control valve partially closed) but the fire alarm system itself is fully functional.
Yes. NFPA 72 §23.8.7.1 permits alarm silencing (audible notification silence at the panel) after the signal has been acknowledged by a trained operator. However, the visual alarm indicators remain active and the system cannot be reset until the initiating device is restored to normal. Silencing the NAC outputs in the field while the fire is still active is a separate decision made by the incident commander.
Cross-zone verification requires two initiating devices in separate sub-zones to both report alarm before the FACP enters full alarm condition and activates suppression systems. It is typically used for pre-action or deluge suppression systems in high-value or hazardous areas to prevent accidental discharge from a single faulty or nuisance-activating detector.
NFPA 72 does not set a mandatory wait time before system reset. Reset timing is determined by the AHJ and the building's fire emergency plan. In practice, the FACP should not be reset until the fire department arrives, confirms no fire condition, and grants permission. Premature reset can clear alarm history needed for the fire department's investigation.
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