Strange noises at night
Recently, people in many apartment buildings reported hearing all kinds of sounds such as chopping boards, chopping meat, The sound of knocking, hammering, pulling chairs, hitting balls, children playing, running, falling marbles… These sounds come suddenly during lunch break, and can be heard even more clearly in the quiet night, causing annoyance. disrupting family activities, even causing stress and insomnia for residents.
Ms. Pham Thi Thom (30 years old, living in an apartment building in Thanh Xuan district, Hanoi) said that there were times when she was working late at night and was suddenly startled to hear a sound like a marble falling. bouncing on the floor and then every day I heard the squeaking sound of nails being pulled at tables and chairs at 12 o’clock at night.
“At that time I thought I didn’t understand whose family had the “passion” to clean the house in the middle of the night. At night like that, whose children are still playing and refuse to go to sleep? Sometimes I feel very frustrated!” Ms. Thom shared and added that because she lives in an apartment, every sound seems to be above her head, and she can’t tell the exact direction from where it comes from.
Mr. Nguyen Van Truong – a construction engineer of a large corporation specializing in the construction of high-end hotel urban areas explains this phenomenon. Accordingly, there are many causes leading to strange noises in apartment buildings There may be people who do such actions.
Mr. Truong analyzed that children on the upper floor or even the upper floor would drop marbles in the hallway or move tables and chairs evenly. affecting the lower floor. “If the action happens on a tiled stone floor, it will make a clearer noise than a wooden floor,” Mr. Truong said.
Besides, the engineer was half-hearted. associated with the construction of high-rise apartment buildings, note the “water hammer” effect in buildings, specifically in apartment buildings with plumbing systems including wastewater drainage lines kitchen, bathroom, washing machine and axial rainwater drainage on the balcony. The drainage system of the apartment on the upper floor is located in the apartment on the floor below. At first the pipe will be dry, but when the water is poured, it will hit the wall of the pipe, causing a small, gurgling sound and a loud, rushing noise. This sound penetrates the concrete layer creating all kinds of sounds depending on the vibration frequency. This phenomenon is called “water hammer”.
Not to mention the long axis pipe is fixed to the wall with screws. After a period of use, the belt loosens when water is poured down from the upper floor, the force can cause the pipe to collide with the screw, creating a resonance force that causes strange noises.
Engineer Truong added that currently, apartment buildings often only install double-layer safety glass that does not have the effect of soundproofing and heat insulation, so outside noise can still be heard indoors.
< p>“Those are factors that cause both subjective and objective noise. This phenomenon appears both day and night. But because the space is quiet at night, we hear those noises more clearly,” he said. Cuong said.
New technology for high-rise construction
Answer the question of why this strange noise phenomenon occurs commonly in high-rise buildings. In an apartment building in Vietnam, Mr. Truong said that domestic investors want to optimize profits, so investing in equipment for good sound insulation is almost non-existent like building a hotel.
” I have worked on high-end 5-star hotel construction projects. Staying in these buildings, I can confirm that it is almost impossible to hear any noise around because the construction has very high standards for construction. Noise is minimized to ensure guest comfort,” Mr. Truong cited as evidence. At high-end hotels, the walls between the rooms from the upper floor to the lower floor and the inside and outside of the balcony door and main door must all be soundproofed.
High-end hotels use boxed glass To insulate sound and heat very well, the water pipe is also a soundproof pipe designed in a tube-in-pipe style, in the middle of two pipes with a soundproof layer. Therefore, when guests on the upper floor pour water and move around, even late at night, the furniture downstairs is not affected.
According to Mr. Truong, Vietnam has not yet manufactured this type of soundproof pipe, so when When building high-end hotels, contractors often have to import materials from abroad.
In addition, this experienced construction engineer also said that it is important to build walls of adjacent rooms. It is also necessary to build an opening and insert soundproofing material in the middle. Applying such high construction standards can eliminate 90% of the noise.
“When accepting the project to put it into use, the hotel operator will stand in the other room causing all kinds of noise and there are people standing in this room, using a sound intensity meter, the result must be almost 0 for the project to be accepted, meaning the soundproofing standard must be up to 55dB,” said engineer Truong. more.
Talk about the thickness of the apartment floor and problems related to hearing sounds. According to Mr. Cuong, the concrete floors between apartment floors today are usually only 15 – 20cm thick and not soundproof. Currently, there are more specific apartment buildings that when constructing the floor, the contractor uses box floor gloss construction technology to make the floor thicker, thus also somewhat reducing the noise from the upper floors. However, most apartments in Vietnam cannot limit these noises.
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