Indoor Environmental Quality: Acoustics and Indoor Air
The interior
acoustics of a space can have a big impact on people’s general wellbeing and
health, so it’s important to get it right. A great starting point is
understanding how sounds react with materials. Acoustics is the study of sound. The
primary purpose of acoustic design is to manage the sound within the space
effectively. As a result, the acoustics of a room should be considered at the
start of the interior design process. Unwanted sound is called noise. It’s our
job to anticipate possible sources of noise and to design spaces that control
this potential noise. The interior design team usually helps in making the
perfect decisions when they know the purpose space will be used for. As a
result, every space should be treated
acoustically to make people feel comfortable and enjoy the space. Without
proper acoustic treatment of an area, sound can become noise, which will impact
people’s experience directly.
The acoustics
of a room needs to be treated or regulated for efficient noise control. This
process includes using acoustic panels in the walls and floor treatments to
reduce the reverberation time, reduce noise, and make speech intelligible. All
materials absorb some sound. Usually, materials will also be rated with a
noise-reduction coefficient (NRC). This is the
measurement of how much sound is absorbed by a given material. It is a simple
number index range from 0 to 1 which represents the % of sound that is not
reflected of the material, in most cases the structural materials and surface
finishes, back into the room. Like NRC, all material assemblies have a
sound-transmission class (STC). This refers to the capability of a material to
absorb sound and considers the entire frequency spectrum and the associated transmission
loss (TL) to provide a single number that describes sound transmission for typical
human hearing.
Reverberation
time is the time taken in seconds for a sound signal to decay by 60 decibels
(dB) once the source stops sounding. This is due to continued multiple
reflections in a space. When a sound wave strikes a surface such as a floor,
wall or ceiling, the direction of travel is changed by the reflection.
Reflection of sound waves follows the same physical law as light – the angle of
incidence equals the angle of reflection. The denser a material is, the sounder
energy is bounced back into the space. A more porous material will reflect
less, reducing the amount of energy in the space and shortening the
reverberation time.
As humans, we spend more than half of our lives indoors. It’s been shown that indoor air can contain two to five times more pollutants than outside air. The quality of the air inside of a building (Indoor Air Quality, IAQ) is impacted by several factors including the HVAC system, access to natural ventilation, the interior materials, the interior furniture, fixtures, and equipment and moisture within a building. Indoor pollutants consist of undesirable substances that make their way into the air supply. These include volatile organic compounds (VOCs) released by indoor products, biological contaminants, minerals, radiation, metals, and water vapor that can lead to mold spores. Poor indoor air quality can lead to a variety of physical symptoms ranging from mild to severe reactions. These include irritation of eyes and throat, dizziness, fatigue, and asthma. With this being said, selecting interior materials and furnishings for good IAQ is a critical aspect to the design.
IAQ and COVID-19
Clean air is beneficial
for human health as it impacts the regular metabolism of our body. Indoor
air quality does play a crucial role in both the widespread of sick building
syndrome and the transmission of COVID-19. It’s been reported that air quality in cities around the world has
suddenly improved — but obviously this hasn’t happened in the way anyone would
want. A decrease in traffic and commercial and industrial activity due to the
COVID-19 pandemic has caused a temporary decrease in pollution. The cleaner air is also a reminder of how deadly
air pollution is. The World Health Organization says dirty air, both indoors
and out, cuts short seven million lives annually worldwide. They report in both residential and commercial spaces,
the use of sanitizers and disinfectants enormously increased in response to
COVID-19. These products are necessary for eliminating the virus, but most
cleaning products significantly harm indoor air quality. They review how Chlorine-containing
products, quat-containing products, and hydrogen-peroxide-containing
substitutes produce chemical byproducts that pose substantial health risks,
especially for those exposed on a consistent basis like janitors and cleaning
staff.
Also, ensuring proper
ventilation with outside air can help reduce the concentration of airborne
contaminants, including viruses, indoors. Proper ventilation also reduces surface contamination by
removing some virus particles before they can fall out of the air and land on
surfaces. “Indoor spaces are more risky than outdoor spaces
where it might be harder to keep people apart and there’s less ventilation.”
Give special consideration to increased ventilation when occupancy is high.
Also, make sure high-traffic areas have additional ventilation. In addition to
helping reduce risk from airborne transmission of viruses, improving ventilation
also benefits indoor air quality by reducing exposure to products used for
cleaning and disinfecting potentially contaminated surfaces.
https://www.epa.gov/coronavirus/indoor-air-and-coronavirus-covid-19
Erica,
ReplyDeleteI loved your blog post on IAQ. I think it's something we don't think often about and yet it is so important to our health. You did a good job explaining IAQ in relation to the pandemic. Your points were very clear. I also appreciated that you talked about different options for reverberation and sound can be treated within a room to help reduce the noise intake. Overall, great job!
Erica,
ReplyDeleteI enjoyed how specific and detailed you were about reverberation, diffusion, and absorbing sound and acoustics. You also mentioned how sound absorbing materials can be used for different things other than acoustics. Such as the aesthetic and style of the space, by softening surfaces, or creating a pop of pattern or detail.
Erica, I loved how detailed your post was, your explanation of the different sound waves and reverberation times were very well said. I also enjoyed the diagram of how sound and material interact. Overall really nice blog!
ReplyDeleteI think you did a really good job of explaining sounds and acoustics. It was interesting to read in detail how sound functions and I think it better helps you understand the solutions that are discussed later in the post.
ReplyDeleteI thought you did a great job explaining and summarizing the chapter. I also thought your connections between air quality and COVID were well done. Your connection with occupancy was really interesting. Cycling new air is important, but it also really depends on the occupancy of a space.
ReplyDeleteErica,
ReplyDeleteYou provided a detailed and interesting summary of the material we covered this week. I also appreciated the articles you used as your resources for this topic. I particularly thought the Kaiterra article was thought provoking. It seems like best practices are still being formulated concerning IAQ and Covid-19 sanitary procedures. It is always a fine line when using sanitizers and disinfectants. Optimizing fresh air, humidity levels and air filtration will always be effective strategies. As interior designers this will be an ever evolving topic. Total points: 50/50