Noise Control of Industrial Fans
It goes without saying – industrial fans make a lot of noise. They’re big pieces of machinery, made up of heavy-duty components, put together to complete a big task of providing insulation, releasing exhaust, and providing cooling within work environments, industrial factories, and manufacturing facilities, which usually house large amounts of workers.
Noise of industrial fans
As important as industrial fans’ purposes are, the loud noises they make while turned on can be detrimental to the people they’re serving. It becomes a problem within a working environment (and even in any neighboring residential neighborhood or commercial complex) – the noises can pose as a distraction, and even a pain, to one’s hearing and productivity. Noise then becomes a hard but necessary challenge to figure out when it comes to industrial fans.
That is why many manufacturers stress the importance of ensuring noise control and/or minimization when it comes to producing high-quality industrial fans. It remains a vital factor many consumers look take into consideration when choosing an industrial fan. Luckily, there are many solutions that work around this problem.
What is industrial fan noise?
Firstly, to understand “noise control” better, we have to ask: What is “noise?”
Industrial fan noises comprise of the sounds a working fan emits due to the turbulence effect of the fan blades as it rotates from the fan shaft. It could also be the sound of its working motor. The noise becomes louder especially for oversized fans (usually of industrial size) or fans that operate at a higher speed to cater to a bigger need. A higher speed increases the vibrations produced by the fan, hence causing higher noise levels.
Sometimes, it is also merely the design of the air movement system within the industrial fan. The air velocity inside makes unwanted noise due to the fan itself and its interrupted air flow – an effect caused by a host of possible factors or sources: inlet/outlet sound power, pressure values, the environment it is in, the kind of fan used, the size, different motors, efficiency of speed control, and many other considerations.
Therefore, it is crucial to carefully consider all sources of the occupational noise. After that, it’s time to find concrete ways to address the noise control problems of your fan, based on their root causes.
Why is noise control important?
As mentioned, many manufacturers go through many lengths to ensure that noise control is managed within their fans, because of its significance in user consumption. It’s not surprising that companies and consumers alike would rather not have their heavy-duty fan making equally heavy-duty noise. It can become a severe detriment to one’s everyday life: noise pollution. Many cities’ safety protocols specify that noise levels should be kept at a safe minimum, for optimum and safe noise control.
Continuous high levels of noise will affect workers in the short and long term – aside from high daily stress levels, the noise may develop critical hearing loss eventually. And it isn’t just the workers affected – children and elderly from the nearby residences will also be affected. This is why local governments stress these kinds of noise control ordinances within their city, applied to construction sites, manufacturing facilities, operations, and production sites, which usually define allowable decibel ranges, appropriate noise levels, and a curfew for working.
Ways to address noise control in industrial fans
There are various noise control techniques different manufacturers use in addressing certain occupational noise problems. The techniques used really depend on finding out what about the fan is specifically causing the unwanted noise (a crucial step before solving any problem), but there are a few general techniques that are commonly used to suppress the noise.
The most important goal in mind when achieving prime noise levels is how best to decrease the intensity or volume of the sound in a controlled environment that you cannot change. This is called noise attenuation – the loss of energy from sound waves. This is what we want to achieve – damping the sound in order to decrease the volume and quality of the sound wave. So, what can be done to the current fan system to address the noise it is emitting?
Simple noise control techniques
One basic means is to address this problem from its very root – to install components or other systems within using techniques, like damping – this is used when noise is coming from the fan’s chutes, conveyors, panels, and hoppers.
Others also use premium, high-end silencers that are purpose-designed, like silencers that are specifically built to address the loud fan hums or whines that are usually present in the food industry facilities. These stack silencers can reduce the droning noises of fans by a lot of decibels by attacking the process exhausts of the fan, and the supply fan itself. You can also use duct silencers to address noise coming from a ducted part of the fan.
However, these silencers usually have acoustic absorbent splitters inside, which can gravely affect the flow resistance of the air inside, causing extra stress on the fan. Therefore, it is equally important to use a silencer which provides lower flow resistance as well, causing less load on the fan, and so ensuring its longevity as well as a machine.
Preventive noise control
Another technique used from the get-go is choosing the right equipment. Of course, it’s always best to select machines that are made of premium, high-quality materials and tools, even if they are a bit more expensive, as they on their own can contribute greatly to noise attenuation in the beginning. Make sure to select efficient compressors, fans, motors, engines, blowers, and other components that can efficiently come together for your desired noise control level.
You can also acoustically treat individually key components of your fan – either the ventilators, fans, panels, or blowers. Maybe there’s a loose bolt in the panel that needs tighter screwing, a poorly-closed shaft, uneven tool application, poor balance between parts that just needs some fine-tuning, or a barrier or enclosure not properly closed, which could cause vent noises. Sometimes, it is also just a matter of adjusting your fan speed. As mentioned earlier, a common factor of high noise is the speed control of your fan – having an expert take a look at how fast and hard your fan is going, and diagnosing it properly, may do wonders.
Effective noise control equipment
When it comes to industrial noises like rooftop fans, loud chillers, building ventilation systems, noise control equipment can also be installed, like acoustic louvers, which are used when ventilation air is required. They become a part of the exhaust air system of structures that helps reduce the noise made by the system’s equipment.
Noise control enclosures are also specially engineered acoustically to damp the sound level.
Sometimes, duct lining is also applied for ventilation systems that make use of absorbent material within, like foam, fiberglass, or other similar cloth or material. When you line their ducts with a special material, this will decrease noise.
Isolation pads for vibrations are also used for noise control, starting with vibration control. These anti-vibration additions (like springs or machine mounts) help to decrease the noises produced by high vibration levels. Similarly, acoustic flexible connectors are also used when it is the fan blade and its rotation that are causing the noise. This noise is also caused by high levels of vibration, so the flexible connector helps to contain that.
Acoustic blankets can also be used to address noise coming from the casing of equipment using high-density material (in the form of sound blankets).
Ferrari Ventilation has been manufacturing top quality industrial fans since 1963.