Which data types do sources such as NIST or DIPPR provide to support source term calculations?

• A. Vapor pressures, boiling points, heat of combustion, densities.
• B. Optical properties and color indices.
• C. Viscosity and refractive index only.
• D. Thermal conductivity and heat capacity.

Answer: (A)

When modeling a release and potential combustion, you need properties that describe how the material behaves as it leaves a container and what energy is involved if it burns. Vapor pressure tells you how readily the substance will enter the gas phase under given conditions, which helps predict how much of the material becomes airborne. The boiling point indicates the temperature at which a liquid becomes vapor, informing whether the release will be dominated by vapor or liquid at the incident conditions. The heat of combustion tells you the energy released during burning, shaping flame behavior, heat release, and the overall impact of the event. Densities are essential for converting between mass and volume, and for estimating concentrations and plume dynamics. Sources like NIST or DIPPR provide these core thermophysical properties to support accurate source term calculations. While optical properties, viscosity, or refractive index, and even thermal conductivity or heat capacity have their roles in broader modeling, they are not as directly central to determining release behavior and energy release as the combination of vapor pressure, boiling point, heat of combustion, and densities.