Although it is a rare incident, but according to engineers, experts, the elevator floor door can be opened without a cabin in some situations such as safety surveillance circuit "undercut", deadbolt .
The incident of Marine University student Dao Yen Thanh falling into an elevator without cabin on December 14 made many people worried because this is a popular means, especially in cities.
Meanwhile, school leaders are still waiting for conclusions from the police about the cause of the incident.
According to engineer Nguyen Van Huynh (Corporation 789, Ministry of Defense), the elevator is operated by a system of pre-processing circuits that are very scientific with very high safety. However, during the installation process, contractors can "trim" some of the system's safety monitoring circuits, causing the risk of accidents.
Specifically, the most basic error may be caused by "trimming" the safety monitoring circuit at the floor door and cabin (elevator barrel) so that the door is not closed but the ladder is running; or the floor door is still open when the cabin has not arrived. This makes the user experience especially dangerous situations such as being stuck in the door, falling into the elevator hole.
The door opened and the boys fell inside and fell freely from the 5th floor. (Photo: Youth).
Mr. Huynh did not rule out that the maintenance staff were working and forgot to close the floor, causing the male students to lose their feet freely to the ladder. In the situation of Marine University boys, according to Huynh's analysis, the cause could be the elevator panel's fault, or some other powerful effect that made the floor of the door open.
Meanwhile, Mr. Tran Vu Phong - Consultant of Viet Long Elevator Company (in Binh Hung Hoa Ward, Tan Binh District, Ho Chi Minh City) said that the opening of the floor door without elevator cabin is something very unlikely.
Between the floor door and the elevator cabin door there is always a latch, when the cabin comes to each floor, the cabin door opens and the door pulls the floor door open.
Maritime University blocked the elevator having trouble leading to the death of the male student Dao Yen Thanh.(Photo: Phuong Chi).
"In case the door is open without a cabin, it can break the pin . At that time, the cabin has not reached that floor, or has passed but the door is still open," the expert said.
In addition, there are cases where maintenance elevator staff are maintaining, forgetting to close the floor and leaving somewhere and causing people to lose their footsteps when entering the elevator.
According to Mr. Phong, the elevator incident in general due to maintenance process missed some technical errors, not promptly repaired. The responsibility for these incidents belongs to elevator management units and maintenance companies.