Quantification of Elevated Hydrogen Cyanide (HCN) Concentration Typical in a Residential Fire Environment Using...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Laser Spectroscopy

Background:

• Hydrogen cyanide (HCN) is a toxic gas produced in fires.
• Accurate, real-time monitoring of HCN is crucial for firefighter safety.

Purpose of the Study:

• To develop and validate a portable, time-resolved measurement system for elevated HCN concentrations.
• To assess HCN levels in simulated fire environments.

Main Methods:

• Direct absorption tunable diode laser spectroscopy (DA-TDLAS) was used.
• The system employed the R11 absorption line of HCN at 3345.3 cm^-1.
• Calibration and validation were performed using known HCN concentrations.

Main Results:

• The system demonstrated a relative uncertainty of 4.1% at 1500 ppm HCN.
• Immediately Dangerous to Life and Health (IDLH) levels of HCN were exceeded at all tested heights (1.5 m, 0.9 m, 0.3 m).
• A maximum HCN concentration of 295 ppm was recorded at 1.5 m height.

Conclusions:

• The developed portable HCN measurement system is effective for time-resolved analysis in fire scenarios.
• The system successfully detected hazardous HCN concentrations in simulated fire environments, highlighting significant risks.
• The system's capability was demonstrated in full-scale residential fire simulations.