Which of the following is not a direct effect of wind speed on a surface pool fire hazard near ground level?

• A. The inherent chemical reactivity of fuel.
• B. Flame stretch and tilt.
• C. Evaporation rate.
• D. Downwind radiative heat exposure.

Answer: (A)

Wind speed mainly changes the way a surface pool fire behaves by altering the flame's shape and how heat moves around, not the fuel itself. The flame tends to stretch and tilt with wind because the surrounding air pushes the flame and bends its flame front downstream, which directly affects how heat reaches objects ahead of and beside the fire. Wind also influences evaporation by boosting convective heat transfer to the liquid surface and by carrying away vapor more quickly, increasing how fast the fuel can vaporize into the flame. Downwind radiative heat exposure changes as the flame’s height and tilt shift the path of radiant energy toward surfaces downwind, altering the hazard area. The inherent chemical reactivity of the fuel, however, is an intrinsic property of the fuel itself and does not change with wind speed, so it’s not a direct effect of wind in this scenario.