Noise Barrier has been applied to numerous scenarios in the
past and the most popular application would be the side of roads where traffic movement is of abundance.
Back when researching on Noise Barrier was not prioritized, many countries resorted to using concretes and woods for their noise mitigation solution.
Now, many research has been done and comparison has been made between those mediums to see its effectiveness and performance. Mediums like concrete, hollow block, vegetation are used especially in countries that are developing and have grown interest in being more responsible for the environment.
Concrete barriers has been effective back in the days until people found out that having such system means having to accept that the barrier has to be heavy, costly and only reflects noise away from receiver.
Hollow block barriers are a much better improvements from the concrete barriers. The internal structure of this barrier has 'holes' that dissect the sound wave traveling through it, disrupting its 'energy'. Even though these blocks are lighter than concrete blocks, it still is heavy and requires a lot of man hours / manpower for installation.
Vegetation barriers are, however, a better way to go head on with environmental issues. Though such system has very minimal noise mitigation properties, its capability to reduce carbon emission and its aesthetics properties are seen to be a far better choice to the other earlier option.
The innovation Noise mitigation system
Noise mitigation system was developed to counter noise problems from its source. Basically, having such system allows the receiving end to receive lesser impact of the noise where research has gathered that prolong exposure to noise with have significant negative impact on the receiver's health.
Over the years, government involvements in decreasing noise pollution brought about changes to be made to the mitigation system. Changes brought about to the old system forces companies to innovate the way noise barriers are suppose to be. Factors such as its performance, its man hours needed to install and the manpower needed to install on site, all plays an important factor to innovate a new version of the product.
The involvement of government bodies further encourages researches to be carried out to develop findings on the various performance for different barriers used in the past up till now on various location. A research done in Malaysia concluded as below:
Vegetation recorded the lowest insertion loss in this study. The concrete hollow blocks are fairly effective as noise barrier to protect receivers from traffic noise pollution. Moreover, the concrete panel has stable and sufficient insertion loss recorded during measurement session. This was also due to diffraction and refraction of noise waves by the flat and solid surface of concrete hollow blocks facing the highway. The cavities inside both concrete hollow block and concrete panel noise barriers help to absorb the noise from traffic on the highway. The precast concrete panels perform a consistent insertion loss throughout all measurement periods as compared to the concrete hollow blocks. This is correlated to the fact that the concrete hollow blocks also need to rely on wall joint between the
blocks; rather than depending only on the cavities to reduce the noise. As the construction of concrete hollow blocks noise barrier includes a lot of joint between blocks as compared to the precast concrete panels, there is possibility that the sound leakage occurs between the joint and reduces the insertion loss of concrete hollow block noise barrier.*
*Research source: https://ac.els-cdn.com/S1878029615006337/1-s2.0-S1878029615006337-main.pdf?_tid=06b88653-3bdf-44cc-bf04-542b660887e1&acdnat=1528166229_ee3c6c65194fbe5373cb603f98ddc584
Few years back, Hebei Jinbiao, started with poly-carbonate panels where sponge like materials are used as the mechanism to mitigate the noise. However, the performance was acceptable but soon became unproductive for the amount of work put in place for the installation.
Soon after, the government set in place a performance criteria to be met which led to innovations and new era of products to be brought in to Singapore for both temporary and permanent works.
Metal Shell Panels
The introduction of Metal Shell Noise Barriers proves that noise mitigation system has heighten its standard. The availability of panels for both temporary and permanent serves different purpose, however, both panels offers better performance, more cost efficient and produces a better aesthetics capability to the other counter parts.