One of the main indicators by which the quality indicators of fire doors are determined is the fire resistance limit, usually it is indicated in minutes. Fire resistance is a period of time during which the doors can resist the fire without losing their main protective functions. The minimum fire resistance is 15 minutes, and the maximum is 120 minutes. What is the limit at a particular door is established by tests that are carried out in accordance with the requirements of the fire safety standard. After testing, based on the results, the doors are certified.
Reliable fire doors, such as those made and sold here - are marked with the following data:
- product name, manufacturer name;
- indicator of fire resistance;
- batch number;
- Description of the manufacturing technology of the door.
In the event that the fire door with glass, it must be marked accordingly. On the product itself there is a marking consisting of one, two or three letters - R, E, I.
The letter R denotes the loss of the bearing capacity of the door, this is a complete destruction of the structure or the formation of irreversible deformation. E - loss of integrity, this is when the occurrence of deep cracks through which fire, smoke can penetrate. I - loss of heat-insulating properties, this is when the door trim material from the side not directly exposed to the fire is heated to the maximum permissible temperature. To one of these letters or to a variant of their combination, the time in minutes is indicated, this is the period for which the change indicated by the letter will occur.
For example, the designation REI 30 indicates that all three indicators, or one of them, will be lost 30 minutes after the start of exposure to the door of intense fire. As tests have shown, a residential or office building will completely burn out in 15-40 minutes, therefore, the minimum fire rating for a door cannot be less than 15 minutes. Which side it is necessary for the fire door to open, how it should be hung - on the right or left canopy, depends on the direction in which people will move to the exit in case of fire. In some operating conditions, installation of door closers is required, but in general, to select a fire door, it is enough to take into account the above parameters.