On the website for your region you will find information on the products relevant to you, contact details and news.
Unfortunately, there is no Greek language version of our website. However, you can stay on this page or contact our sales representative in Greece directly.
Can you make it a little quieter? ZIEHL-ABEGG fans impress with the best acoustics in every application
Acoustics generally refers to the scientific study of sound, its origin, propagation, perception, and effects. Among other things, acoustics is used to investigate and reduce noise. A basic prerequisite for the propagation of sound is the presence of matter, i.e., a gaseous, liquid, or solid medium that carries the sound waves. The nature of the carrier medium has a significant influence on the speed at which sound propagates, known as the speed of sound.
If the sound is generated aerodynamically, i.e., by the movement of air molecules, this is referred to as aeroacoustics.
Did you know: What is the speed of sound?
Noise is not only unpleasant to perceive, but in extreme cases can also have a serious impact on health. Sound pressure, sound power, and frequency are three physical quantities that can be used to quantify noise levels.
Sound pressure refers to pressure fluctuations caused by sound waves in a solid, liquid, or gaseous medium. Sound pressure is measured as a force acting perpendicular to a surface in pascals (Pa). gemessen. The sound pressure level is influenced by the distance between the sound source and the receiver, as well as any obstacles, e.g., in a room, and is therefore a location-dependent variable.
The human hearing threshold is approximately 0.00002 Pa, and the pain threshold (depending on personal sensitivity to noise) is approximately 20 Pa. To simplify this wide range, the sound pressure level is expressed on a logarithmic scale and quantified in decibels (dB).
Sound power (= source strength) refers to the energy emitted by a sound source per unit of time and is therefore a location-independent variable. Sound pressure thus forms the basis for calculating sound power and enables an objective comparison of different sound sources regardless of the ambient conditions. Sound power is calculated by integrating the sound pressure and is expressed in watts (W).
Similar to the sound pressure level p, the sound power level P is also expressed on a logarithmic scale and specified in decibels (dB).
Frequency is a measure of the number of periodic events (e.g., sound wave vibrations) that repeat themselves in a given unit of time. In acoustics, frequency indicates how often a sound signal vibrates within one second, or how many repetitions of a continuous vibration follow one another within one second. Frequency is measured in hertz (Hz), with 1 hertz corresponding to one oscillation per second.
The frequency range audible to humans is between 16 and 20,000 Hz (20 kHz).
Due to the fact that human hearing perceives sounds of equal sound pressure but different frequencies as having different volumes, the frequency spectrum of a sound source is evaluated.
This evaluation is performed using three different filters, which are defined from A (below 55 dB) to C (above 85 dB). The sound power level, taking into account the A filter, is often used in connection with ventilation systems and the corresponding numerical value is given in dB(A).
In addition to air flow and electrical data, the acoustics of ventilation products are also carefully tested and are subject to standards and norms. Measurements are usually carried out in an anechoic chamber test bench, in a test duct, or as a free-field measurement. The number and positioning of microphones is specified by relevant standards.
The fan to be tested (test specimen) can be tested in different installation types or in different measurement categories (see ISO 13349):
Tested innovation: ZIEHL-ABEGG's InVent development center has the largest and most modern combination test bench in the world!
Measurement methods for the acoustic evaluation of fans are regulated by the International Organization for Standardization (ISO) in specific norms and standards to enable comparability and reproducibility:
A ventilation system consists of various components and therefore contains different sound sources that generate different types of noise (examples):
Aerodynamic noise caused by turbulence and swirling air is the dominant type of noise in a ventilation system.
Impellers can be optimized for efficiency and acoustics
Additional components (e.g., filters) can become clogged and should be checked regularly.
Flaps on the air inlets and outlets can cause mechanical noise and/or flow noise.
Improved acoustics in confined installation conditions: ZAflow from ZIEHL-ABEGG
The installation conditions of a ventilation system have a significant impact on its efficiency and noise levels. Examples of important influencing factors include
The operating point of an air handling system has a direct influence on its noise emission. A technically qualified and precise design can significantly reduce the noise level during operation.
In addition to the design measures directly on the fan (primary measures), depending on the installation situation, application requirements, and cost situation, further secondary measures such as sound insulation or sound attenuation can be taken to reduce the noise pollution caused by an air handling system.
Sound attenuation refers to the conversion of the energy of sound waves in the form of vibrations into another form of energy. Sound attenuators can be used in various types or designs. For example, absorption sound attenuators can absorb sound energy and convert it into heat through the use of porous or fibrous materials.
