How far can it detect?
Detection distance comes down to hot spot size, lens, and pixels on target. Three pixels on the hot spot is the design basis for accurate temperature; the figures below are for a Flir A70.
Systems Engineers
What you need to know about designing for thermal as a site’s primary fire detection method.
First to UL 2684
First to UL 2684
Custom Zones and Thresholds for the Earliest Reliable Alarm
Alarm logic runs on the camera and is configured to the hazard. Define where to look, what counts as an alarm, and how each rule communicates with the fire alarm control panel or monitoring system, delivering early warning and fire alarm functionality from the same device.
Alarm Types
Choose the detection logic that best matches your application.
🌡
Absolute Threshold
The zone exceeds a set temperature.
↗
Rate of Rise
Temperature climbs faster than a set number of degrees per minute.
Δ
Delta
The zone runs hotter than a reference, such as a neighboring asset or the ambient temperature, by more than a set margin.
◎
Growing Hot Spot
The share of the zone above a temperature grows past a set percentage.
Alarm Zones
Customize monitoring areas and alarm behavior for individual hazards.
▣
Full Coverage or Individual Hazards
A zone can span the entire field of view or be drawn around one asset.
⊘
Inclusion and Exclusion Zones
Watch what matters; ignore heaters, reflective surfaces, or anything that should never trigger.
☰
Stacked Zones with Different Logic
Multiple zones can overlap, each with its own alarm type, setpoint, and output. Full-view zones can give an early supervisory signal at one temperature and a fire alarm at a higher one.
20
Up to 20 Zones per Camera
Each mapped to a dry-contact output or a network alarm.
Three Integration Pathways. One Camera.
One camera, three connections. The fire alarm pathway is the listed one; video and data are supplementary. Video can run through an on-site VMS server or, with no server at ll, through Flir Aura cloud monitoring.
⚠
Fire Alarm
Digital I/O
Alarms to the FACP
Connect the camera to the fire alarm control panel through digital inputs and outputs.
✓ Dry contacts: Alarm, Supervisory, Fault
✓ Listed addressable input modules on the SLC
✓ 24 V DC listed, supervised power
✓ Wiring and programming per FACP manufacturer, NFPA 72, and AHJ
▶
Video Monitoring
ONVIF
Video to the VMS
Stream thermal and visual video to your video management system, or monitor through Flir Aura.
✓ ONVIF Profile S/T: thermal and visual video, overlays, alarm events
✓ Flir Latitude or any ONVIF VMS
✓ No server? Flir Aura cloud provides web-based alarm handling, trending, and mobile alerts
⇄
Data Integration
Modbus TCP
Data and Alarms to SCADA
Share temperature measurements, alarm information, and diagnostics with industrial control systems.
✓ Temperatures, alarm status, event flags, diagnostics
✓ Polled or event-driven
✓ Any Modbus TCP master: SCADA, historian, BMS
Common applications for thermal imaging fire detection
Where the hazard produces heat long before smoke, and where high ceilings, airflow, dust, or outdoor exposure make conventional detection slow or impractical.
Early Fire Detection by the A70
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640 × 480 radiometric thermal imaging plus a 1280 × 960 visual camera for instant context at alarm
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35 mK thermal sensitivity and ±2°C accuracy, calibrated at every pixel
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On-camera alarm logic with up to 20 regions of interest: threshold, rate-of-rise, delta, and area-percentage triggers
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Alarm, supervisory, and fault dry-contact outputs to the fire alarm control panel; Modbus TCP, MQTT, Ethernet/IP, and ONVIF for SCADA, BMS, and VMS
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29°, 51°, and 95° lens options with 3 × 3 pixel detection distances to 125 m (410 ft)
- IP66, 24 V DC or PoE, rated for indoor and outdoor installation
Detect faster. Respond smarter.
Thermal imaging allows you to design a system that detects threats, not just responds to them. FLIR's Axx Series is UL 2684 listed, prescriptive under NFPA 72, and supported by FLIR from layout through commissioning.
Questions we hear from engineers
Both models come in three fields of view: 29° for the longest reach, 51° as the general-purpose choice, and 95° for wide coverage at short range. The A70 is built for long-range and wide-area monitoring, giving the best detection at the greatest distance and the highest performance: EV fleet and bus depots, warehouses, large combustible piles, and other large hazards. The A40 is ideal for smaller or individual hazards and room monitoring: hydraulic pump units, pump rooms, electrical gear, battery charging stations. Both carry the same listing, alarm logic, and outputs.
No. Thresholds are configured by the installing contractor at commissioning behind a password-protected interface, documented in the acceptance record, and retested after any change.
The dry-contact alarm, supervisory, and fault outputs. Modbus TCP, MQTT, Ethernet/IP, and ONVIF are supplementary paths for SCADA, BMS, and VMS and are outside the listing.
From the Discover Center
