Online Database of Industrial Noise Sources
167
Sound fields at the workplace are usually complex because of the involvement of
many sources in the process of sound generation, propagation and absorption: propagation through air, propagation through solid matter, reflection from the floors, walls,
ceilings and machinery surfaces, absorption on the surfaces, etc. The noise control
measures should be performed only after an appropriate study of noise sources. The
basic mechanisms of noise generation can be due to mechanical noise, fluid noise
and/or electromagnetic noise.
Noise produced from electrical equipment such as motors and generators is generally low-frequency noise. Electrical motors convert electrical energy to magnetic
energy then to the mechanical energy. Since part of the transformed energy is
converted to heat energy, the electric machines should be supplied with cooling
systems, quite often fan systems that generate noise.
Air-moving equipment tends also to generate noise with a wide frequency range.
Air turbulence and vortices generate noise, especially at high air flow velocities.
Turbulence may be generated by moving or rotating solid objects, such as the blade
tips of a ventilator fan. Therefore, care must be taken to reduce flow velocity, reduce
turbulence flow by using diffusers and removing obstacles to the flow.
For mechanical sound sources, care must be taken to reduce the vibrating surfaces
and to reduce the vibration velocity. Reduction of the vibration velocity can be carried
out by using damping materials at resonance frequencies and by blocking the induced
forced vibration. Reducing the vibrating areas can be carried out by separating a large
area into small areas, using flexible joints.
Due to the needs of industry and economic development, there is an increasing
demand for cost-effective consumer goods. For the machine manufacturer, this generally means offering products with a low space, material, energy and production time
requirement. Increased production and productivity are often accompanied by an
increase in noise levels. The staff are then exposed to higher noise levels than before,
despite the noise reduction measures taken in the design of the machine. Noise is a
common occupational hazard in workplaces such as the industries of steel and iron,
crushing mills, foundries, sawmills, airports and aircraft maintenance workshops,
textile mills, among many others.
3 Request
The database of noise sources is intended to describe industrial noise source. Noise
emitted by industrial sources may depend on many factors, but the database should
be simple and practical to use and should contain minimal number of data that
describe noise sources. Since the main reason for design of the database was statistical
analyses, the relevant data that describe the results of measurements of industrial
noise sources are:
• name of the noise source;
• description of noise source and/or measurement conditions;
167
Sound fields at the workplace are usually complex because of the involvement of
many sources in the process of sound generation, propagation and absorption: propagation through air, propagation through solid matter, reflection from the floors, walls,
ceilings and machinery surfaces, absorption on the surfaces, etc. The noise control
measures should be performed only after an appropriate study of noise sources. The
basic mechanisms of noise generation can be due to mechanical noise, fluid noise
and/or electromagnetic noise.
Noise produced from electrical equipment such as motors and generators is generally low-frequency noise. Electrical motors convert electrical energy to magnetic
energy then to the mechanical energy. Since part of the transformed energy is
converted to heat energy, the electric machines should be supplied with cooling
systems, quite often fan systems that generate noise.
Air-moving equipment tends also to generate noise with a wide frequency range.
Air turbulence and vortices generate noise, especially at high air flow velocities.
Turbulence may be generated by moving or rotating solid objects, such as the blade
tips of a ventilator fan. Therefore, care must be taken to reduce flow velocity, reduce
turbulence flow by using diffusers and removing obstacles to the flow.
For mechanical sound sources, care must be taken to reduce the vibrating surfaces
and to reduce the vibration velocity. Reduction of the vibration velocity can be carried
out by using damping materials at resonance frequencies and by blocking the induced
forced vibration. Reducing the vibrating areas can be carried out by separating a large
area into small areas, using flexible joints.
Due to the needs of industry and economic development, there is an increasing
demand for cost-effective consumer goods. For the machine manufacturer, this generally means offering products with a low space, material, energy and production time
requirement. Increased production and productivity are often accompanied by an
increase in noise levels. The staff are then exposed to higher noise levels than before,
despite the noise reduction measures taken in the design of the machine. Noise is a
common occupational hazard in workplaces such as the industries of steel and iron,
crushing mills, foundries, sawmills, airports and aircraft maintenance workshops,
textile mills, among many others.
3 Request
The database of noise sources is intended to describe industrial noise source. Noise
emitted by industrial sources may depend on many factors, but the database should
be simple and practical to use and should contain minimal number of data that
describe noise sources. Since the main reason for design of the database was statistical
analyses, the relevant data that describe the results of measurements of industrial
noise sources are:
• name of the noise source;
• description of noise source and/or measurement conditions;