Solutions which minimise the structural noise generated by a vibrating source at a given frequency, getting this frequency out of the audible range. These are elastic solutions with a high buffering coefficient which allows for the attenuation of the unwanted vibrations and change the resonance frequency of the system.
Acoustic problem: Vibrations
Vibration comes from the Latin vibratio. It is the process and the consequence to vibrate: periodic movement or sway over a equilibrium position.
Most of the current buildings include one or several HVAC & R (Heating, ventilation, air conditioning and refrigeration) systems; which by the characteristics of its function, produce a cyclic mechanical movement which generates noise not only by the transmission of noise to the air, but also by the unwanted transmission of vibrations, usually to the ground.
These vibrations can travel long distances through structural materials within buildings, reaching the surfaces of some enclosures, which radiate airborne noise to the air particles adjacent to the contour elements.
Dynamic and vibrational considerations are underestimated during design, resulting in subsequent errors of machinery functioning as well as in the generation of unwanted noise and structural stress.
Many of these problems can be solved either through preventive measures in the design phase, or through corrective measures once the malfunction has been identified.
Consequences of vibrations
- To the health of the people, Vibrations generated by machinery used in the workplace, generate negative consequences on the human body. When the vibrating surfaces come into contact with the human body (back, head, limbs, hands) a mechanical aggression is produced whose effects may be discomfort, reduction of efficiency or even injuries and pathological states.
These effects are due to oscillating forces which are physically offset by three mechanisms:
1 The muscular tension
2 Tissue compression.
3 Tissue mass acceleration, producing joint stress.The measures are not only refer to the contact with the human body, but also the airborne noise induced by low frequencies, in these cases the human being is ill-adapted.
- To the building structure. vibrations can cause failure in the structures which result in safety problems. The vibration is due to the mechanical resonance of the structure. This resonance occurs when the dynamic forces are equal to the natural frequencies of the support structure (sympathy phenomenom). In resonance, the forces are amplified up to 20 times and make the structure vibrate above the limits of safety.
- To the performance of the machinery. Vibration causes premature wear of the mechanical parts shortening the expected lifespan of the equipment. The lack of dampers or the bad choice in a vibrating equipment can cause a mismatch, disrupting the proper functionality, and even cause a system failure. In fact, inadequate vibration levels in a structure may indicate the principle of an internal equipment failure, which if not fixed, may cause total rupture. Assuming costly repairs, disruption of activity, or even risk of injury.
Vibration can be controlled in three points of the vibratory phenomenon, source, medium and receptor.
The most effective way to control the vibration is at the source. If you have a noisy equipment the most coherent thing is to treat it, this will be the most effective and cost efficient solution. If by other circumstance it is not possible to control this point you should consider treating the medium or the receiver.
A method to treat the source is to provide vibration damping, isolating through the structural disconnection of the vibrating machine from the base floor with interspersed elastic materials.
What is dBbalance AV?
These are formulations designed to obtain the maximum damping coefficient and loss factor, with the proper rigidity reaching an optimal deflection without interfering in the machine or performance or installation.
Learn more about Anti-vibration structural noise systems in our catalog.