- Author
- Waller, D. J.
- Title
- Post-Fire Hydrogen Fluoride Concentration Decay Modeling for Fluorinated Fire Suppression Agents.
- Coporate
- Worcester Polytechnic Inst., MA
- Report
- Thesis, May 27, 1998, 201 p.
- Keywords
- fire suppression | hydrogen fluorides | decay | toxicity | mathematical models | conservation | equations | temperature | pressure | heat transfer | mass transfer | ft-ir | fire tests | water
- Identifiers
- single control volume compartment model; HFDECAY.EXE - the computer application; HF model results
- Abstract
- Flourinated fire suppression agents produce significant concentrations of hydrogen fluoride (HF) when discharged into a fire. The lingering concentrations of HF following suppression are a major concern from the standpoint of toxicity and corrosively. A mathematical model has been developed to estimate HF concentration decay with time following fire suppression. The model solves control volume conservation equations for species mass, temperature, and pressure, as well as heat transfer, mass transfer, and condensation rates for the control volume. HF concentration decay is based on absorption into water that has condensed within the compartment, flow out of the control volume by mechanical ventilation and extraction, and flow out a user-specified leakage area due to pressure differentials across the control volume boundary. The model has been validated against HF concentration decay data gathered using FTIR technologyd during two full-scale U.S. Coast Guard clean agent fire test series conducted in mock engine room compartments. Comparisons of measured and calculated results show an average difference of 15.3% and 9.3% for the time- and 5-minute average HF concentrations, respectively. Model calculations show that the results are quite sensitive to the size of the vent area as well as the total surface area available for water film or water droplet absorption of HF.