A measurement of the total amount of combustibles is known as ______ ______.

The correct term to describe the total amount of combustibles present in a given area is "fire load." This concept is significant in fire safety and prevention, as understanding the fire load helps fire departments assess the potential risk and severity of a fire in a structure.

Fire load is typically measured in terms of weight per square foot of the area it occupies. It quantifies how much material can contribute to a fire, which includes anything that can burn, such as furniture, building materials, and other fuels. By evaluating the fire load, fire safety officials can devise appropriate strategies for fire prevention, control, and response.

The other terms provided relate to different aspects of fire science. For example, the auto-ignition point refers to the minimum temperature at which a substance will ignite without an external source of ignition, and BTUs (British Thermal Units) measure the energy content of fuels but do not directly assess combustibles in a space. The fire combustion process describes the chemical reactions during burning but is not a measure of the total combustibles present.