Machine Noise and Acoustic Enclosures
Machine noise can often be a problem and the best way to deal with this is to cover the unit with a soundproof enclosure. The enclosure itself needs to be fabricated from heavy materials to block the noise and a sound absorbent lining will improve things further by reducing the amount of reverberation that would otherwise build up inside the box. Structural contact between the enclosure and the machine must be avoided otherwise acoustic vibrations will be transmitted to the enclosure walls and re-radiated outside. If the noise is structure borne then simple anti-vibration isolators can help as shown in the illustrations below but these will generally only reduce the low frequency components below around 100Hz from transmitting into the building.
If this type of anti-vibration is required in addition to an acoustic enclosure then M20AD high density resilient mats can be used. For extra heavy machinery contact our technical department for advice.
Acoustic Foam or complete soundproof Enclosure Kits can be applied inside enclosures to reduce reverberation and block sound/damp vibrations to reduce the overall noise levels experienced away from the machinery.
If the machine is larger then the following images may help you understand what needs to be achieved.
The following diagrams show the design and effectiveness of various machine enclosures using our products:-
Original Machine. Approx: 0dB reduction
Adding our Anti-Vibration Pad. Approx: 2dB reduction
Adding our SoundBuster screen or an Acoustic baffle to one side. Approx: 5dB of reduction
Adding a heavy sealed acoustic enclosure. Approx: 20 - 25dB of reduction
A heavy sealed acoustic enclosure, Anti-Vibration Pad and Acoustic treatment. Approx: 40 - 55dB of reduction
A double enclosure with Anti-Vibration Pad and Acoustic treatment. Approx: 60 - 80dB of reduction
For exceptionally large and heavy machinery it is often impractical to enclose them within a soundproof enclosure. Noise problems associated with machinery such as heavy pressing machines, are more normally structure borne and of low frequency. Airborne noise is not usually an issue with these but if it is, mobile acoustic screens such as SoundBuster screens will help screen and absorb airborne noise. The structure borne sound is more complicated to address and would entail mounting the machinery onto a heavy concrete block that would be sunk into an acoustically lined pit and as shown in the detail below.
This type of acoustic insulated pit will contain and absorb a high degree of structure borne vibrations and therefore, making working life more tolerable for other employees.
Also see our article on smaller noise pumps and compressors HERE
Written by Stephen Young
© Sound Service (Oxford) Ltd 2006