BrandSafway, Belgium

Energy Intensive Processes

Reduce noise pollution from an industrial installation

Noise pollution is an invisible hazard that surrounds us everywhere in our lives. Dwellings are notably subject to regulatory maximum sound exposure levels. This is why any plant located in an urban area is subject to strict noise level rules.

Sound exposure limit levels in homes: maximum 45 dB(A) in the evening and at night

Several houses near the production site of an industrial zinc producer in Belgium experienced high noise exposure levels at their facades. 

Following measurements carried out in these dwellings by an acoustic design office, it turned out that the noise levels were too high compared to the maximum authorised levels, reaching in particular sound levels of between 37 and 46 dB(A), in the ranges of 800 and 1600 Hz.

After applying a penalty of 5dB(A) as a kind of safety buffer, the production site reached an emitted noise level of 51dB(A), which was still 6dB(A) above the maximum defined by regulations.

At this stage of the study, it was suspected that an industrial fan was the main source of noise pollution. After making an inventory at the whole production site, the entry and exit ducts of the fan were identified as main sources of noise. These ducts have huge diameters of between 1,000 mm and 1,500 mm.

Accordingly, a more detailed study of the sound intensity at the industrial fan level was carried out:

  • At the existing sound enclosure and fan motor

  • At the intake duct

  • At the outlet duct

  • At the oil tank and appendages

To reduce noise emission, the ducts had to be acoustically insulated. The acoustic design office specified a minimum sound attenuation per octave band with which the insulation system had to comply.


A customised sound insulation solution with ULTIMATE™ light stone wool

The contractor BrandSafway Belgium (BEIS) was commissioned to supply and install a suitable insulation system.

Together with Saint-Gobain ISOVER Technical Insulation Benelux, BEIS made various acoustic calculations for the selection of the appropriate pipe insulation system (according to ISO 15665). For this, the teams used data from acoustics laboratories in which Saint-Gobain ISOVER had previously acoustically tested various pipe insulation systems.

Proposal ISOVER for the case

Finally, an insulation system was installed consisting of 100 mm U TECH Wired Mat MT 4.0 (made of the light stone wool ULTIMATETM), in combination with a loose aluminium cladding layer and acoustically decoupled support rings.

U TECH Wired Mat MT 4.0 was chosen because, compared to traditional mineral wool solutions, it proved to be the most efficient insulation solution. Where competitors proposed much heavier insulation systems (7 layers of insulation + support rings), fewer layers of U TECH Wired Mat MT 4.0 were required to achieve the same level of performance. In addition, U TECH Wired Mat MT 4.0 is a lightweight stone wool and therefore much easier to handle and to install around these large pipes.


Very easy to use and an impressive sound reduction

- Feedback of the contractor, Eddy Vorstenbosch (BrandSafway Belgium)

Lots of benefits, even beyond acoustic performance

In short, here are all the advantages brought to this project through our ULTIMATE™ light stone wool range:

Safety & Installation time

  • 4-5 fewer layers to install

  • No additional mass layers needed

  • Less weight

  • No need to weld support rings

  • Less downtime required for installation


  • Fewer products to transport

  • No additional mass layers to transport


  • Equivalent performance

  • 59% less raw materials used

  • Less waste


A result that complies with acoustic regulations

The noise measurements carried out after the end of the insulation work show that the noise pollution is no longer audible at the housing level and that the noise level complies with the regulatory values.

Acoustic Insulation of an industrial fan in Belgium