Industrial noise is an everyday hazard for factory workers that can affect productivity, product quality and even result in worker turnover. Exposure to high levels of noise can also lead to hearing loss.
OSHA sets standards for acceptable noise levels in factories and manufacturing plants, and ignoring noise control can result in fines and even closure of the facility.
Constrained Layer Damping
Industrial noise control is a growing concern, and new technologies are being developed to reduce vibrations that make machines rumble. Traditional damping techniques stick a high-damping material to metal surfaces, but constrained layer damping puts the dampening material between two sheets of metal. This approach is 30% more efficient than conventional methods, because it prevents the dampening layer from deforming as it bends and vibrates.
Constrained layer damping is a common way to minimize vibrations in vehicles, for example. It is an excellent solution for eliminating squeal on wheels, because it can be applied to the wheel web.
This type of damping is also popular in home theaters and speaker building because it reduces wall resonance, and will dramatically reduce interior noise levels for speakers or acoustic panels. It can be used to line door panels, firewalls, floor pans, trunk lids and many other areas inside a vehicle.
It is also a good choice for automotive applications because it reduces the total noise produced by the car and will improve its overall ride quality. However, it is important to note that it does add a significant amount of weight to the structure.
Another option for controlling vibrations in vehicles is free layer damping. This technique is very popular in the industry, but it can be quite difficult to implement. It’s also a bit limited in its effectiveness, so it is not ideal for large-scale projects or lightweight structures.
One form of constrained layer damping is called MCLD, which stands for “magnetic constriction layer damping.” This treatment uses arrays of specially arranged permanent magnetic strips that are bonded to viscoelastic damping layers. The strips can improve the compression or shear characteristics of the damping layers, depending on their configurations.
Active Noise Cancellation
In industrial noise control applications, active noise cancellation is an effective technique. This is achieved by generating a sound wave that is equal and opposite to the machine noise emitted.
A key advantage of this method is that it is able to reduce the noise level without increasing the overall acoustic pressure. In addition, it is often more energy-efficient than other solutions.
ANC can be implemented in electronic equipment such as audio amplifiers, networking equipment, and air conditioning systems. Silentium offers the S-Cube Development Kit to help system designers develop a custom solution for their specific application.
The most common application of active noise cancellation is on headphones and speaker systems. It is a technique that is popular among both consumers and manufacturers of headphones, as it can significantly reduce the level of noise in a space while retaining sound quality.
However, ANC doesn’t work well on irregular sounds like voices and honking. ANC works best on sounds that are steady and consistent, such as drones and hums.
Another form of ANC is feedback ANC, which relies on audio that is already close to the user’s ear to cancel out noise. This approach is more energy-efficient than feedforward ANC.
Aside from the feedback ANC approach, there are a variety of other active noise cancellation methods that are available. Some of them include passive noise reduction and constrained layer damping.
Passive Noise Cancellation
Noise is an unavoidable part of many industrial environments. While it can be an important function, too much noise can affect the health of workers and their equipment. The key is to find a solution that is safe and cost-effective for the workplace.
One solution is passive noise cancellation, also known as PNC. These headphones use their natural shape and materials to block noise from reaching the ears. Unlike active noise cancelling (ANC) headphones, which have powered microphones and require battery power to activate, passive headphones do not.
There are several types of PNC systems, including passive earbuds and custom-fitted headphones and in-ear monitors. In-ear headphones are especially effective at blocking sound, as they typically have thicker ear cups that create a seal around the ear and reduce sound transmission through the ear canal.
If a headphone has ANC, it uses mics inside the earcups to listen to outside noise, then generates an anti-noise waveform to effectively “cancel out” the ambient sound before it reaches your ears. In order to do this, the mics must be able to accurately detect and invert the phase of the noise they are listening to, as well as calculate the time it takes for that noise to travel from the microphone to your eardrum.
Another type of ANC technology is adaptive noise cancellation, which adjusts the amount of noise cancellation depending on the level and nature of background sounds. Adaptive ANC can be quite effective, but it requires a more complex design and is usually more expensive.
Passive noise cancellation is an excellent choice for a wide range of industrial applications. Whether you are looking to eliminate the sound of your compressor or reduce noise from your vacuum pumps, passive headphones are an excellent solution.
Injected Foam
Injection foam is a unique type of insulation that can be used to improve a building’s insulation levels. It combines the functions of insulating, sealing and air-sealing all at once. It can be injected into cavities that may not have adequate insulation, such as masonry walls and concrete block.
It’s a water-based material mixed with an isocyanate and polyol resin, which react to create an expanding foam that fills the cavity. It then hardens to create a seal that prevents thermal transfer and air leakage.
Like other forms of insulation, it helps to reduce heat transfer, which can help keep a building warm in the winter and cool in the summer. In addition, it can block sound transmission and reduce the noise produced by vibrations.
This form of insulation can be installed in existing walls, but it’s most commonly used in new construction. The installation process involves a crew drilling holes in stud bays and injecting a non-toxic, water-based resin and foaming agent into the cavities. Once it has completely filled the wall cavity, access holes are sealed with wood or foam plugs.
The foam itself is a durable, long-lasting solution that can last for many years. It’s not prone to compressing, settling or sagging and remains effective even when exposed to harsh weather conditions.
In addition, it has one of the highest R-values per inch of any insulation on the market today. The higher the R-value, the better it performs as an insulator and as a barrier to sound transmission.
Injection foam is available in different sizes and thicknesses to meet your insulation needs. It can be a great option for retrofitting old homes that may not have adequate insulation levels, and it can also be added over fiberglass insulation to boost the R-value in your home’s walls.
Emerging Solutions
Industrial noise pollution is a serious problem, especially when it affects residents near factories and construction sites. Solutions for industrial noise control reduce the impact of loud machinery and mechanical plants on nearby residents and workers, lowering noise-related health hazards.
Increasingly stringent noise legislation and environmental planning aim to mitigate the effects of industrial noise on people living in surrounding areas. This has led to a growing demand for new technologies and innovations that can help solve the problem.
One promising solution is a system that takes inspiration from noise-canceling headphones. It consists of panels that use sensors and speakers to disrupt sounds from outside.
This technology is still in development, but it holds the promise of being a low-cost and efficient way to dampen noisy equipment. It’s also relatively easy to implement.
Another emerging approach for noise reduction uses an of-the-shelf soundproofing foam that’s injected with a nanopowder. This creates microscopic channels that absorb sound 60 to 100% more effectively than the foam alone.
Many of these innovative methods for noise mitigation hold the potential to be game changers for Fan Noise Control. However, it will take time for some of these to become widely available.
Some startups, such as QuietStar in the United Kingdom, offer soundproofing solutions for factories, mechanical plants, and construction sites. They develop solutions that reduce the effects of noise on the nearby community and workers, easing their stress and reducing noise-related health problems.