Why High-temp Measurement Keeps Thermal Imaging Useful in Extreme Heat

Inside a structure fire, temperatures climb fast. Flashover conditions can exceed 1,000°F (538°C). That’s exactly when firefighters need the most information from their thermal camera, and exactly when a standard range can wash out into solid white.

A washed-out image is a blind spot. Without gradients and patterns, overheated areas become a uniform “hot blob,” offering no meaningful information about the heat that might be behind a wall, ceiling, or floor.

High-temp Measurement keeps the picture readable when the heat rises. The Sonim XP Pro Thermal puts it in a rugged, FirstNet Ready smartphone built for the fireground.

What High-Temp Measurement Actually Is

 The Sonim Iris app, which includes MyFLIR Pro, works with the

 FLIR Lepton sensor to automatically adjust the gain state based on the scene. Here’s how it works in practice:

• Standard mode: Optimized for everyday temperature ranges and accuracy
• High-temp mode: When objects above 150°C (302°F) fill a large part of the scene, the software switches to low-gain mode and displays objects up to 400°C (752°F)
• Your choice: The automatic switch can be toggled on or off

Extended range comes with a trade-off in accuracy (up to 10% or 10°C). Being able to toggle the switch lets users choose between maximum range and a tighter focus on their objects of interest.

The Problem with a Standard Range

In a fire room, superheated gases, flame impingement, and burning overhead layers can push a thermal camera past its limit. The screen whites out, and the details that guide life-or-death decisions disappear with it.

Practical Benefits: Why High-temp Measurement Matters on the Fireground

1. Early Warning Signs of Flashover and Rollover

Watch for rapidly rising ceiling temperatures, rollover forming, and hot gas layers accumulating while there’s still time to act.

2. Reading Structural Stability

Steel I-beams, trusses, floor joists and roofing members lose integrity as they heat up. High-temp mode helps crews detect dangerously hot structural elements and judge whether a floor or roof may be approaching collapse.

3. Faster, Safer Overhaul

After knockdown, hot spots can hide in walls, ceilings, voids, insulation, and furniture. Because hot areas don’t saturate the screen, crews can find deep-seated hot spots before they rekindle.

4. Monitoring Fireground Hazards

Check compromised electrical panels, overheated motors and appliances, hazardous materials, and gas meters or cylinders exposed to flame with better awareness of explosion or failure risk.

5. Visibility for Search and Teamwork

Keep exit paths, handlines, partners, and obstacles visible, supporting a better victim search even in extreme heat.

The Bigger Picture: Built for Public Safety

• FLIR Lepton 3.5 + MSX: Sharp, high-contrast thermal data with visual edge enhancement
• Certified FirstNet Ready: Access to AT&T’s network dedicated to public safety, with always-on priority and preemption.
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• MIL-STD-810H rated, IP68: Engineered to endure drops, dust, water, and extreme temperatures
• Customizable PTT, SOS, and thermal capture buttons: Designed for glove-on, eye-up operations

Clear Vision When the Heat Is On

Thermal cameras reveal heat. High-temp measurement keeps that heat readable when it matters most. For firefighters, that means better situational awareness, safer interior decisions, and fewer rekindles.

See what the Sonim XP Pro Thermal can do for your team: sonimtech.com/products/phones/xp-pro-thermal