What creates smoke at a building fire?

Smoke at a building fire is primarily created by incomplete combustion and pyrolitic decomposition. Incomplete combustion occurs when there is not enough oxygen to completely oxidize the fuel, leading to the formation of soot, gases, and other particulates that are present in smoke. Pyrolitic decomposition refers to the thermal decomposition of organic materials due to high heat, causing them to break down and release volatile compounds, which also contribute to smoke production.

Complete combustion, on the other hand, typically produces carbon dioxide and water vapor with little to no smoke, since all fuel is fully burned with sufficient oxygen. Pyrolitic decomposition alone would not fully account for the smoke in a fire, as it doesn’t include the factor of inadequate oxygen for combustion. Furthermore, stating that only incomplete combustion creates smoke overlooks the significant contribution of pyrolitic decomposition in producing the varied components found in smoke during a fire. Therefore, the correct choice highlights the combination of these two processes as key to smoke development in a building fire.