how it works
The reduction of transportation noise propagation can be effectively achieved by the use of a screening structure. Such structures are typically constructed as a physical barrier between the noise source and the receiver where noise mitigation measures are deemed necessary. The noise barrier shall typically be an uninterrupted and solid structure.
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Noise reduction from the use of a barrier is attained by the screening effects of the barrier with the receiver protected in the acoustic shadow zone. The noise is diffracted over the top of the barrier, therefore increasing the distance it needs to travel to the receiver. The amount of noise reduction achieved is thus dependent on the path difference between noise source and receiver, with and without the barrier. The higher the path difference, the better the noise reduction is
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Path difference, = a + b - c
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reflective vs absorptive noise barrier
Significant degradation in noise reduction can be expected as a result of the multiple reflections created between the noise barrier and vehicles, especially buses and trucks.
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As can be seen from the example beside, the lorry acts as a reflecting surface and contains the intensity of the noise until it has cleared the reflective noise barrier. This result in little, if any reduction in noise.
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In some circumstances, if there is a parallel reflective surface, this can also reflect the noise on the opposite side of the lorry, doubling the intensity of the noise experienced by the receiver. An acoustically absorptive noise barrier would be much more effective in minimizing such build-up of noise level.
     
     
   
 
ABSORPTIVE
 Soundblox Masonry Block Wall System
  o PerMAP Lightweight Metal Absorptive Barrier System
 
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 Glass Reinforced Concrete (GRC) Noise Barrier System
 
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REFLECTIVE
 PerGLAS Transparent Noise Barrier System
     
     
 
 
SOUNDBLOX is a sound absorbing masonry unit which derives its sound absorption properties from a unique cavity-slot resonator construction, much like how a Helmholtz Resonator works. SOUNDBLOX is very effective in such application, due to its 2-in-1 function;
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It provides excellent sound absorption properties particularly at low frequencies, eg 250Hz to 1000Hz of which traffic noise is most prominent, hence reducing the built up noise level.
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It also provides superior sound insulation property that far exceeds the minimum sound transmission loss required of a noise barrier wall.
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With proper installation, the unplastered SOUNDBLOX wall is capable of achieving a sound transmission loss performance of STC 47 and sound absorption rating of NRC 0.85. It is able to withstand high impact and is virtually maintenance free.
     
     
   
PerMAP metal barrier is a sound absorbing lightweight noise barrier system which offer exceptional noise reduction in the critical traffic noise frequency range. It is a modular system of standard-sized lightweight panels which allows for quick and economical assembly at site. The flexibility embodied in the design of the lightweight panels enables easy integration with PerGLAS transparent panels as and when required.
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Weighing only 25kg/m2, the modular panels are fabricated in a standard module of 2000mm x 500mm, with custom bending design which ensures rigidity of the noise barrier system. Adopting a slot-in installation between two structural H section, the PerMAP metal barrier system enables a quick and trouble free installation.
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features
Weather resistant
Light weight
Impact resistant
Maintenance free
Excellent sound insulation and absorption
     
     
   
As a transparent panel, PerGLAS offers a clear view form both sides. It is a modular system of standard-sized panels which allows for quick and fuss free assembly at site. The flexibility embodies in the design of the panels enables easy integration with PerMAP noise barriers as and when desired.
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With its excellent light transmittance, light weight and formability, PerGLAS transparent noise barrier fits harmoniously into the surrounding environment. Weighing only 20kg/m2, the modular panels are fabricated in a standard module of 2000mm x 500mm, with a choice of colour options and thickness. Adopting a slot-in installation between two structural H-section, the PerGLAS transparent noise barrier system enables a quick and trouble free installation.
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features
Optimal light transmittance
Stable, with good deflection control
UV resistant
Impact resistant
Light weight
Easy maintenance
     
     
 
 
Traditionally, many of the GRC applications were for architectural cladding and mouldings where GRC flexibility of shape, colour and texture together with its light weight can be fully exploited by designers. The use of GRC has been extended to noise barrier since.
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GRC noise barrier system offers both absorptive and dispersive panels in precast form. Coupled with durability and good resistance to chemical, GRC noise barrier system provides an aesthetically pleasing option which requires little maintenance with unlimited design flexibility.

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