Exterior propagation (SI-2)

The regulations aim to ensure that the fire that may emerge outside does not spread to other fire sectors of the building itself or to nearby buildings. To do this, it is necessary that the materials with which the façade and roof are made are stable to fire for at least 120 minutes. It is also mandatory that façade openings, such as doors or windows, that belong to fire sectors or different buildings, be located at a sufficient distance to not allow fire to pass between them.

Evacuation of occupants (SI-3)

The necessary evacuation means for any building are established. In general terms, the evacuation route is limited to 35 metres, with an evacuation route being understood as running between any occupiable point in the building and an exit from the floor, the building, another fire sector or a protected corridor, that is, to an area where the fire cannot extend. This forces large buildings to distribute a certain number of stairs or protected evacuation corridors on each floor, or to carry out greater compartmentalization with small fire sectors.

The width that the evacuation route must have is also established, establishing a width measurement determined according to the number of occupants for hallways, door steps, stairs, and any element used for evacuation.

Three types of stairs are established: the normal ones, called unprotected, the protected ones, which are compartmentalized from the rest of the building with walls and fire doors in such a way that they serve as a refuge in the event of a fire, and the specially protected ones, which add measures such as independent vestibules with double doors designed to prevent the entry of smoke inside. The standard requires the use of a certain type of staircase depending on the risk of fire, the number of occupants and the height to be evacuated.

Fire detection, control and extinction (SI-4)

The mandatory installations are included for each type of use and size of the building, such as fire extinguishers, dry columns, sprinklers, etc.

Action of firefighters (SI-5)

It is mainly dedicated to allowing access for fire trucks, establishing the measurements of the building's surroundings and the loads to be supported to be able to place these trucks. It is also mandatory to have holes in the façade to allow access.

Structure strength (SI-6)

The structure is required to resist for at least a certain time, which varies between 15 and 180 minutes. For most buildings less than 15 meters high, a resistance of 60 minutes is valid, equivalent to an atmospheric temperature in the fire sector of 950 °C.

The resistance of the structure can be obtained through tests, the methods established in the standard or the use of the annexes included in the Basic Document, which include the calculation of resistance for concrete, steel, wood and factory structures.

The annexes establish, in the case of concrete, the thicknesses and coatings necessary for the structure to resist the necessary time. Concrete structures have good fire performance, so it is generally not necessary to apply a protective layer on the structure to comply with the provisions.

Steel structures are greatly affected in the event of a fire so, except in rare cases, it is necessary to apply a layer of protection. At 900 °C, the elastic limit of steel, the main parameter of its mechanical resistance, is reduced to 6% of its value at room temperature. The standard includes 2 ways to resist fire for the indicated time: oversizing the piece so that it is possible to resist the loads even with the reduction in resistance caused by temperature, and covering the steel with insulating protectors that prevent the steel from reaching high temperatures.

In the case of wood, the fire affects only its outermost layer, keeping the interior of the pieces intact. For this reason, the regulations require the pieces to be oversized so that the exterior part can char while the interior continues to resist the loads of the structure. On top of the net section necessary to resist the loads, a thickness of material proportional to the required resistance time must be added to each of its faces exposed to the fire, depending on the carbonization speed, which ranges between 0.55 and 0.80 millimeters per minute depending on the type of wood.

The fire resistance of load-bearing walls is considered according to the stability of the load-bearing walls to fire, and can be increased depending on the coating.

Exterior propagation (SI-2)

The regulations aim to ensure that the fire that may emerge outside does not spread to other fire sectors of the building itself or to nearby buildings. To do this, it is necessary that the materials with which the façade and roof are made are stable to fire for at least 120 minutes. It is also mandatory that façade openings, such as doors or windows, that belong to fire sectors or different buildings, be located at a sufficient distance to not allow fire to pass between them.

Evacuation of occupants (SI-3)

The necessary evacuation means for any building are established. In general terms, the evacuation route is limited to 35 metres, with an evacuation route being understood as running between any occupiable point in the building and an exit from the floor, the building, another fire sector or a protected corridor, that is, to an area where the fire cannot extend. This forces large buildings to distribute a certain number of stairs or protected evacuation corridors on each floor, or to carry out greater compartmentalization with small fire sectors.

The width that the evacuation route must have is also established, establishing a width measurement determined according to the number of occupants for hallways, door steps, stairs, and any element used for evacuation.

Three types of stairs are established: the normal ones, called unprotected, the protected ones, which are compartmentalized from the rest of the building with walls and fire doors in such a way that they serve as a refuge in the event of a fire, and the specially protected ones, which add measures such as independent vestibules with double doors designed to prevent the entry of smoke inside. The standard requires the use of a certain type of staircase depending on the risk of fire, the number of occupants and the height to be evacuated.

Fire detection, control and extinction (SI-4)

The mandatory installations are included for each type of use and size of the building, such as fire extinguishers, dry columns, sprinklers, etc.

Action of firefighters (SI-5)

It is mainly dedicated to allowing access for fire trucks, establishing the measurements of the building's surroundings and the loads to be supported to be able to place these trucks. It is also mandatory to have holes in the façade to allow access.

Structure strength (SI-6)

The structure is required to resist for at least a certain time, which varies between 15 and 180 minutes. For most buildings less than 15 meters high, a resistance of 60 minutes is valid, equivalent to an atmospheric temperature in the fire sector of 950 °C.

The resistance of the structure can be obtained through tests, the methods established in the standard or the use of the annexes included in the Basic Document, which include the calculation of resistance for concrete, steel, wood and factory structures.

The annexes establish, in the case of concrete, the thicknesses and coatings necessary for the structure to resist the necessary time. Concrete structures have good fire performance, so it is generally not necessary to apply a protective layer on the structure to comply with the provisions.

Steel structures are greatly affected in the event of a fire so, except in rare cases, it is necessary to apply a layer of protection. At 900 °C, the elastic limit of steel, the main parameter of its mechanical resistance, is reduced to 6% of its value at room temperature. The standard includes 2 ways to resist fire for the indicated time: oversizing the piece so that it is possible to resist the loads even with the reduction in resistance caused by temperature, and covering the steel with insulating protectors that prevent the steel from reaching high temperatures.

In the case of wood, the fire affects only its outermost layer, keeping the interior of the pieces intact. For this reason, the regulations require the pieces to be oversized so that the exterior part can char while the interior continues to resist the loads of the structure. On top of the net section necessary to resist the loads, a thickness of material proportional to the required resistance time must be added to each of its faces exposed to the fire, depending on the carbonization speed, which ranges between 0.55 and 0.80 millimeters per minute depending on the type of wood.

The fire resistance of load-bearing walls is considered according to the stability of the load-bearing walls to fire, and can be increased depending on the coating.