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Ken:
I heard that there will be a meeting of
apartment-management-association today at Jim’s house at the
third floor of the condominium behind our house. According
to him, the association has several noise complaints among
neighbors, who live at above floor and below floor. They
have hard time in solving this complaint by the belows, who
suffer from noise caused by the above. Dad, you are engaged
in the job of measurement and analysis of noise and
vibration at the company, don’t you? Why does the noise go
through the thick slabs or walls between rooms? How can we
prevent this kind of noise?
Dad: People including
you, Jim and I live in environments which can be roughly defined as
houses, schools or offices or outside surroundings such as roads or
parks etc. People hope that they want to live in a comfortable space in
any cases. Especially in a house which is required relaxing atmosphere,
they want to live in a quiet space without unwilling noise. In
particular, if there is a student preparing for exam, he can not
concentrate on his study disturbed by the noises such as neighbor’s
chats, music or other miscellaneous noises coming into his room. When
your brother listen to the music by the stereo set at the second floor,
you would say it is annoying in spite that our house is a detached type.
In an apartment where many families live, there may be a different
problem regarding noise than that of a detached house as there is only a
wall or a slab between each family. I often hear a word “floor impact
sound” these days and the problem coming up in Jim’s condominium is the
same one, I suppose…
Ken: Well, sound by
stereo set in such a loud noise as my brother does make me annoyed. By
the way, what do you mean by floor impact sound?
Dad: It is a noise
you hear in a room when people make noises by dropping an object on a
floor, kid’s running or jumping in a room on the above floor. In moving
a chair clattering or dropping a spoon or a coin from a certain height
making a sharp noise, such a sound is called floor impact sound (light
impact sources). In contrast, there is another kind of noise when a
child jumps from a chair or a sofa or pops up and down with a bump. Such
a noise is called floor impact sound (heavy impact sources). The former
sound causes noise complaints when the floor is made of wood which is
used frequently for a condominium floor surface. Wood flooring
superseding “tatami floor (Japanese traditional floor)” recently is one
of the main reasons for complaint increasing. I think there are many
wood flooring rooms in Jim’s condominium as well. In this case, you
could solve a problem to some extent by cushioning such as carpeting
partially, change a house shoes to a less noise-making type, or put a
cushion on the foot of a chair. But in the cases of the heavy impact
floor sound, its performance depends on the slab specification, the
thickness, area surrounded by beams and a kind of floor slab.
Furthermore, to save space for ducts, there is a construction method to
leave a certain vacant space between floors supported by clusters. This
may deteriorate sound condition. To put matter simple, the heavy impact
sound is determined by the design when building a condominium. So it is
very difficult to solve this kind of problem. There is no way but
neighbor’s communicating to avoid disturbing each other. The best way is
to become friends to each other. You will try to meet what your friend
wants and you feel easy when you ask a friend for something.
Ken: The best way is
to be friends to each other, huh. But isn’t there another way in effect,
is there?
Dad: In the case of
floor impact sound, it is clear who is making noise and who is suffering
from it and this clearness makes problem with no compromising of “one
hand washes the other”. Noise depends on sense of respective persons and
the level of uncomfortability differs as well depending on health
conditions or even one’s mood. Recently as there are increasing problems
concerning noise, the standard of noise has been made and started to be
indicated. This is called sound insulation grade classifying the
insulation of sound. Floor impact sound is defined with “L+ numerical
value” and the less the numerical value is, the higher the grade is,
showing the condominium has structure with insulation-concerned. This is
only for people who is interested in purchasing a condominium and not
for people who already have. The condominium where Jim lives must have
no such an indication shown as it was not built recently. Condominium is
a type of community with many families live in one building and there is
no way to live comfortably except to concern each other always keeping
in mind as a top priority that they live together.
Ken: I will ask Jim
tomorrow if they reach some solution. I hope I can explain to him what
dad told me.
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