Air compressors are an efficient means used to fill gas cylinders with high pressure air, power HVAC control systems and pneumatic tools, and a broad range of other mechanical functions. Their biggest drawback is their noise level, which reaches between 70 and 90 dB depending on their rotational frequency, system design, and flow factor.
To control the amount of noise generated by air compressors, industrial facilities employ a few different methods, such as:
- Containing the sound energy by forming sound barriers and enclosures for the machine
- Damping the noise-causing vibrations
- Dissipating the sound energy through various means of sound absorption
Enclosures & Sound Barriers
One method of minimizing air compressor noise is to isolate the device within a sound barrier, which reduces the amount of airborne sound transmitted through walls, floors, and ceilings. The most common material used for this purpose is mass loaded vinyl (MLV). Although MLV is heavy, it is not very thick, making it a viable solution that does not take up a lot of space.
Typical applications for sound barriers include:
- Cab floors
- Engine compartments
- Machine enclosures
- Pipe wraps
Studies focused on attenuating radiated compressor noise concluded that sound absorptive material by itself is ineffective in dealing with frequencies produced by large reciprocating air compressors between 63 Hz and 125 Hz. However, installing an enclosure component with acoustical absorptive lining around the intake sufficiently reduces the sound energy through wave reflection and cancellation.
One of the primary sources of air compressor noise is vibration. Although most air compressors are equipped with rubber feet to provide vibration damping, the wear from long term use and their overall inefficiency make them largely ineffective.
Employing vibration damping material, such as constrained layer damping (CLD), diminishes the amount of airborne and structure-borne noise produced by decoupling the air compressor from its installation floor or base. The material also reduces the amount of vibration experienced throughout the system, increasing the overall machine stability.
Some of the equipment for which vibration dampers are commonly used include:
- Door and floor panels
- Enclosure cabinets
- Fuel tanks
- Wheel wells
Sound absorbers are porous materials available in foam or viscoelastic fiber forms. Applying these acoustic materials to hard surfaces allows for the absorption—rather than the reflection—of sound, decreasing the amount of airborne noise depending on the type of absorber material. For example, in one case study, wrapping acoustic absorbers made of mineral wool around components or using it to line an enclosure provided an overall noise reduction of 25 dB. The thickness of the acoustic absorbing material employed also influences the level of sound reduction achieved.
Common uses of sound absorbers include:
- Engine compartments
- Home appliances
- Machine enclosures (e.g., for generators, water pumps, and air compressors)
- Medical equipment
- Truck and heavy equipment cabs
When choosing a sound absorption material for your air compressor, it is important to keep in mind potential interactions between your equipment and the material. For gas and electric compressors, specialized materials are available with additional properties, such as adhesive backings and chemical resistance, to prevent undesirable material-machine interactions.
Contact Technicon Acoustics Today
Air compressor noise presents a significant problem in the workplace. However, there are several methods of reducing the amount of noise produced by a facility’s equipment, including using sound barriers and enclosures, vibration dampers, and/or acoustic absorbers.
At Technicon Acoustics, we provide a range of noise reduction products that employ all three of these methods. To learn more about our range of acoustical treatment solutions for air compressors, contact us, or request a quote from one of our experts.