Noise pollution is increasing globally at an alarming rate. It's no longer just about how loud your neighbor's home stereo system is or if they are playing their music too late at night, but rather the fact that noise pollution can now be affecting you and your business even when you're indoors.
What
Sounds and Vibrations Travel Into Buildings
There are many sources of noise and vibration that can be transmitted to a structure's interior from the outdoors, including:
1)
traffic/vibration from roadways, railways, airplanes
2)
wind-driven rain striking building elements
3)
commercial activity nearby
4)
industrial activities
5) air
handling units for ventilation and cooling/heating
6)
building systems
7)
neighboring construction
8) infiltration of high-frequency noise from external sources.
These events can generate low-frequency vibrations, low-frequency sounds, mid-to high-frequency sound pressure levels, speech interference, and noise annoyance.
In
addition to these sources of noise, human activities such as typing on a
computer keyboard, conversations, or phone calls can also generate mid-to
high-frequency sound pressure levels that have the potential to interfere with
regular activity within an enclosed space.
What
Are Some Consequences of Having Inadequate Building Insulation?
Here are
just a few examples of the consequences when the interior acoustic environment
is not designed correctly or insulated:
1) speech
interference can result in poor intelligibility, increased stress levels for
people inside the building resulting in compromised productivity
2)
high-frequency noise annoyance results in workers having to concentrate on
low-level distractions
3)
low-frequency deflections from wind-driven rain can reduce the effectiveness of
air conditioning systems
4) noise
from traffic and other sources can be very distracting, making it difficult to
concentrate on tasks
5)
low-frequency vibration can cause discomfort and fatigue resulting in worker
performance degradation.
What
Is Considered Proper Acoustical Design?
An
acoustic design that creates an interior environment where speech interference,
low-frequency noises (from building components), and high-frequency noises
(from activities within the building) are kept to a minimum is considered
proper acoustical design.
What
Is Meant By Keeping These Noise Sources To A Minimum?
The human
ear can typically hear frequencies from 20 Hz to 20 kHz. To create a proper
acoustic design, the interior acoustics should be able to attenuate noise in
the lower-frequency range (from 20 Hz up to around 500 Hz) and attenuate noise
in the higher-frequency range from 2 to 5 kHz, where people are most sensitive.
The sound levels produced by these two separations of frequencies can be
measured and compared with one another, where the sound level of the lower
frequency range should not exceed 15 dB over the higher-frequency range.
How
can you insulate your building from noise and vibration?
Many insulation products such as AMS 3195 silicone on the market can work well for this purpose, including but not limited to elastomeric coatings, rubber mats, resilient channels, and other products that are made of neoprene or various rubber-like materials. Some of the acoustic insulation products on the market are made from different types of materials such as structural felt - a product made from mineral wool, synthetic fibers, or paper. Make sure any acoustic insulation product you use is compliant with current building codes and meets Type I, Type II, or Type III requirements as outlined in ASTM E 492-98.
Acoustic
insulation products mentioned above can provide a high degree of noise
reduction when blocking mid-to high-frequency sounds from penetrating an
enclosed space. However, low-frequency noise is another story. Low-frequency
sounds are typically transmitted through the actual building materials or
components that form the enclosure of a room or enclosed space. When you look
at how much noise reduction can be obtained by using an acoustic insulation
product, it's essential to remember that what will effectively block mid-to
high-frequency noise may not provide the same degree of stopping for
low-frequency noises.
Final
Thoughts
Building
materials contribute to a structure's enclosure. However, in different ways:
Materials such as drywall, wood panels, or wall studs are used to make partitions that separate one room from another.
Components such as air conditioning ductwork, plumbing pipes, and electrical service entrances penetrate partitions and form the enclosure of space. These components create the potential for noise to travel through these openings and impact other spaces or rooms.
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