In this photo, the walls in an apartment building stairwell have been blackened by smoke that escaped through the door of an apartment unit that was left open. (Busan Metropolitan City Fire and Disaster Headquarters)

South Korean fire authorities recently conducted a test to recreate an apartment fire, through which they demonstrated that one of the most effective ways to reduce damages was by simply shutting the front door of one's home if a fire breaks out there.

In a bid to promote the fire safety procedures recommended by the authorities, the Busan Metropolitan City Fire & Disaster Headquarters held the mock test in which they actually set a fire to a four-story residential building in Nam-gu, Busan, that had been slated for demolition.

The experiment involved setting a fire in the living room of an apartment unit on the first floor and leaving the door open, and seeing how long it took for the smoke to spread to the upper floors. It was found that the smoke escaped the household in one minute, and spread all the way to the fourth floor in one minute and 40 seconds.

The carbon monoxide level measured on the fourth floor, four minutes and 50 seconds after the ignition, was 7,028 parts per million, far above the critical level.

In contrast, leaving the burning unit's door closed prevented the smoke from spreading, and the flames extinguished themselves in 10 minutes due to the oxygen having been cut off.

In this photo, most of the damage from the fire that started inside of an apartment unit was contained inside, due to the front door being shut. (Busan Metropolitan City Fire and Disaster Headquarters)

"In order to prevent additional damage from a fire, it is crucial for the smoke to be contained (within the site)," said an official of the Busan fire authorities, stressing that in the event that a fire breaks out in one's apartment, it is important to close the front door before escaping.

People should immediately escape when a fire breaks out near them, staying low to the ground and covering one's mouth -- preferably with a wet cloth -- to prevent smoke inhalation. But if a fire breaks out far from where you are, one should try to assess the situation to see if escaping is the best option.

"When you are far from the origin of fire, sometimes it's safer to keep as far away as possible from the smoke and wait for rescue workers," the official said. He stressed that blindly leaving one's own residence might put one at risk of inhaling smoke in the hallway.

While human instinct may drive one to flee from a blaze, statistics shows that it is just as important to keep one’s distance from smoke.

There were 14,230 cases of fires breaking out in apartments from 2018 to 2022, according to the National Fire Agency. Of the 180 deaths from the apartment fires, 127 were caused by smoke inhalation -- far more than from any other causes, including 13 deaths from burns.

According to the Busan Metropolitan City Fire & Disaster Headquarters, there have been 4,619 cases of fires in multi-unit residential buildings in Busan in the past 10 years. Only in 6.4 percent of the cases did flames engulf the entire floor, and in only 1.27 percent of the cases did the fire spread to the entire building.

The state-issued manual for escape procedures in case of an apartment fire (in Korean) can be downloaded from the National Fire Agency homepage.