hot spot
A location which has a higher temperature or amount of radiation than surrounding areas.
hot spot: where heat or radiation clusters dangerously
A hot spot is any localized area where temperature or radiation intensity exceeds the surrounding environment by a measurable margin. In thermal imaging, this appears as a bright region against a cooler background. Hot spots matter because they signal equipment failure, energy loss, or safety hazards long before they become critical. They are found by infrared thermography, radiation surveys, or simple contact thermometers, depending on the application and the hazard class.
In electrical systems, hot spots typically form at poor connections, corroded terminals, or overloaded conductors where resistance generates excess heat. A bolted splice in a feeder cable might run at 65 degrees Celsius while the surrounding cable sits at 40 degrees Celsius; that 25-degree difference flags a joint that will fail within months if not repaired. Thermal cameras can scan an entire switchboard in minutes and identify these before they cause fires or arc faults.
In rotating machinery, hot spots appear at bearing races, gearbox housings, or fluid film boundaries where friction exceeds normal operating levels. A degrading rolling element bearing will show a localized temperature rise of 10 to 30 degrees Celsius above the other bearings on the same shaft. Similarly, a cooling line blockage in a motor frame creates a hot spot downstream of the obstruction, visible months before coolant flow fails completely.
Radiation and Chemical Exposure
In nuclear and radiological work, hot spots denote areas of elevated radioactivity concentration. A contaminated floor corner or a piece of equipment with residual radioactive material will register counts per minute orders of magnitude above background. Surveys using Geiger counters or gamma probes locate these before workers enter the area. Hot spots in contaminated sites must be isolated, documented, and remediated according to regulatory thresholds.
The term hot spot is also used loosely in industrial hygiene to mean high-concentration zones of chemical vapor, dust, or fume. These require local exhaust ventilation or engineering controls to protect workers in those regions. Detection depends on the substance: flame ionization for organics, colorimetric tubes for ammonia or chlorine, or real-time monitors for common industrial gases. Any spot that reads significantly above the zone average demands investigation and corrective action.