Which of the following is NOT considered a class of combustible materials?

In the context of combustible materials, the classes referred to in the question are classifications used primarily in fire safety and fire code regulations.

Class K fires involve cooking oils and greases, commonly found in commercial kitchens. They are indeed considered a class of combustible materials, as they have specific fire hazards associated with them.

Class D is associated with combustible metals, which include materials like magnesium, titanium, and sodium. These metals can ignite and burn at extremely high temperatures, making them a distinct category of combustible materials that require specialized firefighting techniques.

Class C fires pertain to electrical equipment and energized electrical components. While these materials can ignite and cause fires, they are not considered a class of combustible materials in the same sense as organic materials like wood or paper.

Class E is not a recognized classification within the standard fire classes. Fire classifications typically include Classes A, B, C, D, and K, but Class E doesn’t correspond to a specific category of combustible materials in this context.

Thus, viewing the definitions and classifications, Class E is NOT considered a class of combustible materials, making it the correct choice.