FIREWALL (the Russian word is borrowed from the German word "Brandmauer", which means "Brand" (fire) and "Mauer" (wall) * EN: firewall; DE: Brandmauer; FR: mur coupefeu; ES: muro cortafuegos; RU: брандмауэр) is the counter-fire wall, which is purposed for the separation of the adjacent enclosed spaces within the single building, or within the two adjacent buildings, with the purpose to prevent the spreading of the fire.

They are used at the underground mines, gas compressor stations, beneficiation plants, within the buildings, which are structurally divided into several independent blocks (administrative-household combined enterprise, warehouse for the material-technical provision, and so on). They make firewalls of the non-combustible materials on the foundations or on the foundation beams, they erect firewalls to the height of the building, so that the firewalls separate the structures (floors, covers, lights, and so on). During this process, firewalls must be above the roof for 60 centimetres, in case if at least one of the elements of the cover (except the roof) or of the load-bearing structure of the roof is made of the combustible materials, and above the roof for 30 centimetres, in case if all the elements of the cover (except the roof) or of the load-bearing structure of the roof are made of the slow-combustible and non-combustible materials.

The firewalls must protrude from the plane of the exterior walls, which are made of the flammable and combustible materials, for 30 centimetres. The limit for the fire resistance of firewalls (the time for the warming of the surface of the wall, which is opposite to the fire, for 160 degrees Celsius) must be at least 2.5 hours. They calculate the design for the firewalls according to the stability, with taking into account the possibility for the unilateral collapse of the structures within the building during the fire. It is acceptable the creation of the holes through the firewalls, the total area of these holes must not exceed 25% of the area of the wall. The filling of the holes (doors, gates, windows) is performed using the non-combustible or slow-combustible material with the limit for the fire resistance of at least 1.2 hours.