Why is it difficult to enter the radio wave of the mobile phone in the elevator?

　Recently, I learned about an urban legend of "how to go to another world with an elevator".When I searched, "I guess some youtuber is going to be tried," the specified image of the plan ...(If you are interested, please yourself)

　This kind of rumor is born because the elevator probably has an image of "narrow and dim sealed space" and can give an eerie impression.

　It is thought that the radio wave situation is bad.I think everyone has experienced that it was out of range when looking at a smartphone in the elevator.

　Why is the communication situation worse in the elevator?

"Electromagnetic shielding" theory

　For now, I examined various theories on books and the Internet.The plausible explanation found first is that electromagnetic shielding is occurring.

　Electromagnetic shielding is a phenomenon in which the internal space surrounded by conductors such as metal (objects that easily pass through electricity) is not affected by outside electromagnetic waves.When I looked it up, the basket of the elevator seems to be surrounded by iron.

　However, some articles said, "In order for electromagnetic shields to occur, it is useless if there is a gap in the metal."Whether the elevator basket is completely surrounded by metals will vary depending on the model and manufacturer, and it seems delicate whether it is fully applicable.

"Concrete" theory

　The next thing that emerged was that the elevator's exit route (a space where the basket moves) is surrounded by reinforced concrete.As it is said that radio waves are difficult to reach near a high building, concrete will significantly attenuate radio waves.

I asked a detailed person

　As a rule of thumb, many elevators with glass windows do not deteriorate.In other words, if there is no glass window, it may be possible that electromagnetic shielding or concrete attenuation may have occurred.We talked to the Japan Elevator Association.

――Is the elevator basket completely covered by metal?

Association: Elevator baskets are to be built or covered with a safe flame -retardant material (by the Building Standards Law Enforcement Ordinance).If it is not made of metal, it is not stipulated that it is no good, but iron plates are often used as high -strength flame -retardant materials.

―― Will electromagnetic shields occur with an elevator basket?

Association: I don't know how much it will affect.The elevator basket is not completely sealed, but I think that some radiation will weaken the radio waves compared to the outside and the radio waves will be interrupted.

　As expected, the answer was that the elevator basket is not completely sealed.However, if most parts are covered, it seems that radio waves are hard to enter.Although it is determined that the route will be covered with flame -retardant materials, how much it will be covered depends on what it will be.

　After further investigating, Hitachi Bil System is interesting.

　When the elevator is moved, the sounds such as motors and conveyors sound.

　When I tried searching on the net for trial, there were many sites related to elevator noise.From here, there is a voice saying that the driving sound is noisy, so it is possible to guess the flow that the walls of the exit and descent are thickened and the radio waves are difficult to reach.

　The noise is an important issue for those who use a room near the elevator.Even in office buildings, it is troublesome to say that there is a lot of rattling during the meeting.

　It may be inevitable that radio waves will worsen for noise measures.Although it is somewhat inconvenient, according to the Japan Elevator Association, it is possible to respond to emergencies even if smartphones cannot be used.

　If you can't use a smartphone, there should be few situations.If you get out of the area in the elevator, why not try a little time to rest your eyes?

Coverage cooperation

Japan Elevator Association

Hitachi Bill System

Production cooperation

QUIZKNOCK

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