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Burnout time is the main indicator of the quality of fire doors
Fire -based doors must have an appropriate certificate, which should indicate the time during which the door can maintain its fire -resistant properties. Some models are designed for 6 hours, although in practice rarely which door can withstand for more than two hours.
On average, the room in an apartment or office is burning out in 20 minutes, which means that the door retains its fire resistance for half an hour. Fires are performed in such a way that in case of fire under the influence of high temperature, they can swell or bend only inward or outside. You must not allow them to expand in the doorbox.