Is Your Soundproof Studio A Health Hazard?

carbon dioxide double wall system firestops humidity mold soundproofing ventilation Jun 05, 2023

If you don't build your soundproof studio correctly you may be introducing some health hazards into your space. In this article I will discuss three common issues with a soundproof room that many DIY builders forget to do that can lead to headaches, fatigue, fire risk, and mold sickness.

1) Firestops

When I work with my soundproofing clients I often find that they have not thought about fire stops. Fire stops are an important part of a soundproof room built using the double wall design. Without fire stops your double wall system acts like a chimney. A fire could start in the walls and expand up into the ceiling within seconds without anyone in the room even knowing there was a fire. The fire could then jump to other rooms in the house or building very quickly.

To prevent this from happening we install firestops at the top of the double wall assembly to block the smoke and flames from entering other parts of your structure. The diagram below shows a typical firestop design.

Notice how the compressed rockwool and fire caulk create a sound barrier from the wood stud and 1/2" drywall. The drywall sits across both studs and seals the 1" air cavity between your two walls. When done properly a firestop will prevent flames from moving into your ceiling.

2) Ventilation

When you build an airtight room you must ventilate it with fresh air. To properly soundproof a room it must be airtight. This means that fresh air from outside the room does not enter into your soundproof structure. Mini Splits and home HVAC units do not provide fresh air unless you install a fresh air intake system. When building your soundproof studio it is very important to install some sort of ventilation system to provide fresh air (ideally from the outside) to your soundproof room.

The reason we need fresh air in an airtight room is that there is a build up of C02 that accumulates in soundproof rooms. When we exhale we breathe out C02 and the build up of C02 has been shown to cause: headaches, dizziness, restlessness, a tingling pins and needles feeling, difficulty breathing, sweating, tiredness, increased heart rate, elevated blood pressure, coma, asphyxia, and convulsions. (Wisconsin Department of Health Services)

Now, the amount of C02 directly impacts the health risk. In most soundproof rooms you would need to go to the bathroom before it became deadly. However, the fatigue, headaches and drowsiness are a real issue at much lower levels. Let's take a look at these numbers from the Wisconsin Department of Health Website:

The levels of CO₂ in the air and potential health problems are:

400 ppm: average outdoor air level.
400–1,000 ppm: typical level found in occupied spaces with good air exchange.
1,000–2,000 ppm: level associated with complaints of drowsiness and poor air.
2,000–5,000 ppm: level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000 ppm: this indicates unusual air conditions where high levels of other gases could also be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.
40,000 ppm: this level is immediately harmful due to oxygen deprivation.

(Wisconsin Department of Health Services)

In my studio I have a CO2 reader. When I first built my studio the levels would easily reach into the 1,000-2,000 ppm range when it was just me in the studio. When we had 3-4 people in there for a couple hours levels would reach around 2,000-5,000 ppm. This is all to say that you don't want stagnant stale air in your studio that leads to headaches, sleepiness and poor concentration.

3) Humidity

Lastly, an often overlooked concern is mold growth from high humidity levels. According to the North Carolina Department of Health and Human Services: mold will almost certainly grow if relative humidity stays at 70% or higher for extended periods of time (NC Department of Health and Human Services). According to Rod Gervais in his book Home Recording Studio: Build It Like the Pros, ideal relative humidity levels for comfort and your musical instruments should be in the range of 30-50% with 45% being ideal relative humidity (Gervais 136).

When designing your soundproof studio it is important to think about how you can mitigate mold growth. The first way is to properly size your HVAC or mini split unit. An oversized unit runs on shorter cycles making it less efficient at pulling excess moisture out of the air. This will lead to high RH in your studio and home. The second way to remove excess water vapor in your room is to install a dehumidifier. I have a dehumidifier in my studio and it works great, but it is loud. During sessions I have to turn it off. A better solution is to install your dehumidifier in a separate room and connect the rooms using a baffle box. This way fresh dehumidified air can enter your soundproof room without the noise of the unit.

Conclusion

When building a soundproof studio it is important to design for fire safety, healthy air and healthy levels of humidity. If you do not follow these guidelines then you run the risk of introducing serious fire risk, the potential for headaches and poor concentration as well as the risk for mold toxins in your studio. Now that you are aware of the risks make sure to design firestops, ventilation systems and humidity regulation in your studio. This way you will ensure you have a comfortable, safe and healthy environment to create music in.

Works Cited:

“Carbon Dioxide.” Wisconsin Department of Health Services, 29 Mar. 2023, www.dhs.wisconsin.gov/chemical/carbondioxide.htm#:~:text=Exposure%20to%20CO2%20can,coma%2C%20asphyxia%2C%20and%20convulsions.

Public Health, Epidemiology. “Mold.” NC DPH: Occupational and Environmental Epidemiology: Conditions That Promote Mold Growth, epi.dph.ncdhhs.gov/oee/mold/conditions.html#:~:text=If%20there%20are%20no%20cold,mold%20will%20almost%20certainly%20grow. Accessed 29 May 2023.

Gervais, Rod. Home Recording Studio: Build It Like The Pros. 2nd Edition, Course Technology Cengage Learning, 2011.

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