The term “firebreak” is used to refer to an interruption in combustible material which helps to stop a fire in its tracks. It can be used to refer to natural features such as rivers and deep ravines as well as man-made firebreaks, created by clearing vegetation to make a gap which a fire will theoretically not be able to leap over. Firebreaks are also built into many commercial structures like skyscrapers, and they are intended to slow the progress of a fire in the building, allowing people to escape to safety and potentially minimizing property damage.
The concept of making firebreaks is ancient. Early humans, for example, cleared the land around their settlements so that their homes and livestock yards could not catch fire. Typically such firebreaks were made by clearing trees and shrubs and plowing up the land to eliminate grass and other materials, creating a section of raw ground with nothing to feed flames. Firebreaks were also integrated into firefighting techniques at a very early stage.
Natural firebreaks have historically helped to control forest fires, which are natural occurrences. Forest fires can actually be quite good for the environment, clearing out dense underbrush, stimulating seed germination, and getting rid of dead trees and similar organic material. Historic forest fires rarely reached the out of control state of modern fires partially because of natural firebreaks and also because they happened frequently, so they had minimal material to feed on.
Creation of firebreaks is often included in the arsenal of techniques which is designed to fight modern forest fires. In some cases, firefighters take advantage of natural firebreaks, sometimes expanding them to ensure that they will be effective, and in other instances they quickly clear growth and plow up the land to create an entirely new firebreak. In some circumstances, they will also set a fire which is designed to consume fuel and create a firebreak in advance of a fire.
If you live in a rural area, your fire department may have reminded you to clear grass, shrubs, and other organic material away from your house to create a firebreak. In addition to protecting your home from fires, this will also help prevent rot, as plant material which is left in contact with the side of a home can create ideal conditions for mold, mildew, and rot in the winter.
In terms of a firebreak built into a structure, firebreaks are typically made from concrete and other materials which are fire resistant. It is important to remember that these firebreaks are not fireproof; in extreme heat, these safety measures can fail, sometimes catastrophically, so it is a good idea to evacuate any sort of burning structure as promptly as possible.