Noise Level for Large Industrial Fans
There are many things to consider when choosing the right large industrial fan – its type, airflow, and density, as well as its safety conditions. However, one important detail some may often forget is the fan’s noise level.
While this is something that rarely comes to mind, it is one of the most important things we have to look at to ensure everyone’s safety in the workplace, especially in environments that use large industrial fans. These environments usually house employees in the cooling, heating, and manufacturing industries who are exposed to its noise for prolonged hours (an average of 8 hours every day). If the fan’s noise level at a workplace is too high and no effort is made to reduce it, an individual could suffer both short-term headaches and stress, as well as long-term, irreparable hearing damage.
This is why we must remember to select our equipment responsibly, and take measures to regulate their noise. Luckily, there are ways to avoid risking your hearing condition as sound can be measured, predicted, and controlled. But before we get into ways that industrial fan noise can be regulated, we need to first understand how it is measured.
How is noise level measured?
Let’s take a step back and understand how sound works! Simply put, the sounds we hear around us are composed of vibrations of air pressure. When our eardrums pick up these waves of air, they also vibrate, and it is these vibrations in our ear that we identify as sounds. As the waves increase in amplitude or pressure, we recognize the sound as louder. When the sound is too loud that it has already become unpleasant and maybe even damaging, this is what we call “noise.”
It is true that not everyone has the same tolerance for noise. There are those who are sensitive to loud sounds, and those who always turn up the music to the highest level on their headphones. However, there are standard thresholds that must not be exceeded in order to keep your eardrums healthy, thus, keeping your workplace safe. This is why it is important to measure your industrial fan’s noise levels regularly.
Industrial fan noise is measured as sound pressure (Lp), which is determined at a point in space using various devices such as a sound level meter or a frequency analyzer. The result should be a value in decibels (dBA), which we can use to determine intensity of sound. In other words, it is what will help us determine whether or not the noise produced will cause unbearable stress to the human ear. Below is a chart of common sounds that we encounter and their estimated decibel levels:
|Common Noise||Sound Pressure Decibel Level (dBA)|
|Jet aircraft (50 ft. away)||140|
Table 1: Common Noise
We must keep in mind, though, that measuring noises, including those that an industrial fan makes, is not straightforward. There are external factors that we have to consider, such as the environment in which the fan operates. A fan located inside an enclosed factory could produce a different noise level compared to a fan in an open, empty field.
What is considered a “safe noise level” for humans?
Many of us use alarm clocks, which emit a noise level of 80 decibels (dBA when they ring). Hearing them doesn’t usually cause pain, even when they’re placed in close proximity to our ears. But imagine having to endure the ringing for 8 hours – don’t you think that might cause damage to your hearing?
Aside from measuring noise level, it is also imperative that we look at the time an individual is exposed to it. According to the OSHA (Occupational Safety & Health Administration), the permissible exposure limit for an individual with a typical work shift at 8 hours is 90 dBA. As exposure time decreases, the threshold for noise level increases, but wherever your fan lies on the chart, there is only a set time that you or your workers can be exposed to it in order to avoid any hearing loss problems.
The table below shows OSHA’s established exposure limits:
|Exposure Limit (In Hours)||Noise Level (dBA)|
|8 hours||90 dBA|
|6 hours||92 dBA|
How can you protect yourself from noise?
Aside from limiting the number of hours one is exposed, there are other ways we can protect ourselves from hearing issues that a large industrial fan can cause. One way is to reduce the intensity or volume of the sound, which is a method called noise attenuation. Many noise attenuation strategies exist, which can be implemented in any controlled setting.
Some make use of damping, which allows the absorption of vibration energy, and as we learned earlier, less sound waves result in less noise. Simply adjusting the fan speed, which has a direct correlation with fan noise, can also help.
Others choose to invest in noise abatement equipment, which may be the pricier option, but are usually a greater investment. These include, but are not limited to:
- Industrial Fan Silencers, which have fibrous absorption materials that can take in acoustic energy and convert it into heat.
- Vibration Isolation Pads, which are made of high-grade neoprene or rubber that can effectively control and reduce vibrations.
- Duct Lining, which are constructed with foam or fiberglass that are excellent at absorbing noise.
- Acoustic Blankets that act as absorber-barriers that block sound.
How to do it right
No matter what type of large industrial fan you’ve purchased and no matter what noise attenuation method you end up choosing, what’s important is that you’ve taken all measures available to protect you and your workers.
Before buying, ask your manufacturer to provide you with the expected sound pressure level based on the environment you will be placing your industrial fan in. Once installed, measure its noise level, and make the necessary adjustments or secure noise attenuation equipment if it is beyond the permissible noise exposure limits. Lastly, it is also essential to educate your workers on the standard threshold, and to also equip them with the proper tools, such as noise-cancelling headphones or noise protection ear plugs.
All these precautions will prove to be the optimal course of action to keep your workplace environment safe.
Ferrari Ventilation has been manufacturing top quality industrial fans since 1963.