Which of the following is NOT a common fire effect?

In the context of fire effects, sound distortion is not typically recognized as a common effect resulting from fire. Common fire effects generally include physical and visual changes in materials and structures caused by heat, such as spalling, where pieces of material break away—often seen in concrete. Color changes are also a frequent observation, as materials can change color due to heat exposure, combustion, or chemical alterations. Crazing refers to the formation of fine cracks in materials like glass, which occurs due to thermal stress from heat.

While sound can certainly be affected by fire in a broader sense, such as when flames create a crackling noise or when building materials collapse, sound distortion itself does not fall under the category of examined fire effects that result from the direct interaction with fire materials and heat exposure. Therefore, it is accurate to state that sound distortion is not a typical fire effect in the same context as the other options presented.