Thermal screening is a non-contact technology that detects variations in temperature. It quickly identifies individuals who may have an elevated skin temperature. This rapid, non-invasive method is suitable for quick checks.
How Thermal Screening Works
Thermal cameras and scanners operate by detecting infrared radiation, which all objects, including the human body, naturally emit. Hotter objects emit more infrared radiation than cooler ones. The device then converts this detected radiation into a visible thermal image or a numerical temperature reading.
Emissivity is crucial for accurate temperature measurement. It describes a material’s ability to emit thermal energy, ranging from 0 (perfect reflector) to 1 (perfect emitter). The human body’s skin has a high emissivity, approximately 0.98, allowing thermal cameras to capture its temperature. Adjusting camera settings for the measured surface’s emissivity is necessary for precise readings.
Common Uses for Thermal Screening
Thermal screening is widely used in public health to identify individuals with elevated body temperature. This application became prominent during infectious disease outbreaks like the COVID-19 pandemic, adopted at locations such as airports, schools, and workplaces. Its non-contact nature helps reduce infection spread during mass screenings.
Beyond public health, thermal imaging has other applications. It is used in industrial inspections to detect overheating components or insulation issues. Building diagnostics also employ thermal cameras to identify areas of heat loss or moisture.
Understanding Thermal Screening Accuracy
Thermal screening accuracy is influenced by environmental conditions and physiological states. Ambient temperature, humidity, and airflow can all affect skin surface temperature readings. For instance, a person’s skin temperature might appear lower in a cold environment, even if their core body temperature remains stable.
Thermal screening measures skin surface temperature, not core body temperature. An elevated skin temperature does not definitively indicate a fever or illness, as factors like recent exercise, consuming hot beverages, or emotional stress can temporarily raise skin temperature. This distinction is crucial; thermal screening is a preliminary screening tool, not a diagnostic one.
Elevated readings require follow-up with a medical-grade thermometer for precise core body temperature measurement and, if needed, further clinical assessment. There is a potential for false positives, where a person without a fever registers an elevated skin temperature, and false negatives, where an infected individual might not have a fever or may have suppressed it with medication.