Nanoscale Ex Situ Thermal Impulse Sensors for Structural Fire Forensics.

Area of Science:

• Materials Science
• Analytical Chemistry
• Forensic Science

Background:

• Structural fire forensics requires accurate determination of thermal events.
• Existing methods for assessing fire exposure can be limited in precision and scope.
• Nanoscale sensors offer potential for high-resolution thermal event analysis.

Purpose of the Study:

• To develop and calibrate nanoscale sensors for measuring thermal impulse (TI) in structural fire investigations.
• To establish a photoluminescence (PL) spectroscopy-based method for TI determination.
• To demonstrate the sensor's functionality in a practical fire scenario.

Main Methods:

• Synthesized nanoscale sensors from lanthanide-doped oxide precursors (Eu:ZrO2 and Dy:Y2O3).
• Utilized photoluminescence (PL) spectroscopy to probe irreversible phase changes in sensors upon heating.
• Developed a spectroscopic calibration by correlating PL spectra to known in-lab thermal impulses (isothermal heating up to 1273 K and 600 s).

Main Results:

• Established a reliable spectroscopic calibration for the TI sensors.
• Demonstrated the ability to determine unknown thermal impulses using the sensor's PL spectrum.
• Validated sensor functionality when dispersed in paint and subjected to heating near drywall.

Conclusions:

• The developed nanoscale sensors are effective for determining thermal impulse in fire events.
• Photoluminescence spectroscopy provides a viable method for interrogating these sensors.
• The paint-dispersed sensors show promise for real-world applications in structural fire forensics.