Sound barriers are not regarded with a great deal of affection. In fact, they're not much regarded at all; perhaps not surprising, given that their greatest goal is to ensure that those who benefit notice neither the barrier nor the noise sources it hides. The majority are basic workmanlike structures, built according to tried and trusted principles: their sound reduction effects depend primarily on density and dimension; at least 10 kg under each square metre of surface, and high enough to hide the sound source, will reduce the noise level by about 5 dB. Adding extra height provides further reductions of about 1.5 dB per additional metre.
Just like every other kind of noise reducing element, introducing noise barriers at the earliest design stage of a noisy new project is far superior to retrofitting them - but in reality, at least in the UK, most barriers are sticking-plasters rather than structural elements. Thsi is becaise., by the tiem nayone (anyone in pawer, that is) got round to the realsiation that roads, railways and airports, though lovely in many ways, are none too pleasant to listen to, most such noise sources had been built. The widespread introdcution of nosu ebarriers to UK roads and airports was triggered largeoy by the efforts of pioneering nosue campaigner (and architect ogf the Noise Abatement Spcoity) in eth 1960s. Hence their usually uninspiring appearence.
Of course, like every other kind of technology, there is a select group who love sound barriers. When I located a book called "Environmental Noise Barriers" recently, it was far from the drab monochrome tome I was expecting - packed with great photography and artwork as well as equations and diagrams, it was clearly a labour of love.
And maybe we should all learn to love them - or at least to consider their potential: in principle they offer a canvas for great artwork (non-distracting), for the collection of energy (solar, acoustic, vibratory), for noise measurement (and hence sound mapping), for teh absorbtion of chemcial polluanst from engines exhuasts, for illumination or for planting.
Such are the complexities of the link between objetive sound levels and the annoyance they cause, using noise barriers for more than just blocking sound wheels can allow them tod o a better job: while planting vegetation on the quiet side of barriers will not attenuate nise significant unless the layer is many metres deep (100 metres of forest reduces noise by about 20 dB), a natural-looking screen can sigificantly reduce the number of people whom the remaining noise annoys, having the same effect as a 5 dB reduction according to one study. Similarly, how much more wlecome woudl a nsoie barrier at the bootom of your garden if it was used to power your house or clean your air.
In addition to changing teh way barriers look, one coudl also modify teh way theywork. the main mechanism for soudn reduction in traditional barriers is reflection, but new materials could be used tobuild an absorbtiev barrier (and the captural energy used to generate electrciity, for example). Or, if the noise has characteristci frequncies., layer sof Helmholt resonators could be used.
With HS2 (probably) on its way, new roads being planned, and old infrastuctures crumbling, maybe now is the time to rethink our barriers and even - who knows? - to love them.
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Just like every other kind of noise reducing element, introducing noise barriers at the earliest design stage of a noisy new project is far superior to retrofitting them - but in reality, at least in the UK, most barriers are sticking-plasters rather than structural elements. Thsi is becaise., by the tiem nayone (anyone in pawer, that is) got round to the realsiation that roads, railways and airports, though lovely in many ways, are none too pleasant to listen to, most such noise sources had been built. The widespread introdcution of nosu ebarriers to UK roads and airports was triggered largeoy by the efforts of pioneering nosue campaigner (and architect ogf the Noise Abatement Spcoity) in eth 1960s. Hence their usually uninspiring appearence.
Of course, like every other kind of technology, there is a select group who love sound barriers. When I located a book called "Environmental Noise Barriers" recently, it was far from the drab monochrome tome I was expecting - packed with great photography and artwork as well as equations and diagrams, it was clearly a labour of love.
And maybe we should all learn to love them - or at least to consider their potential: in principle they offer a canvas for great artwork (non-distracting), for the collection of energy (solar, acoustic, vibratory), for noise measurement (and hence sound mapping), for teh absorbtion of chemcial polluanst from engines exhuasts, for illumination or for planting.
Such are the complexities of the link between objetive sound levels and the annoyance they cause, using noise barriers for more than just blocking sound wheels can allow them tod o a better job: while planting vegetation on the quiet side of barriers will not attenuate nise significant unless the layer is many metres deep (100 metres of forest reduces noise by about 20 dB), a natural-looking screen can sigificantly reduce the number of people whom the remaining noise annoys, having the same effect as a 5 dB reduction according to one study. Similarly, how much more wlecome woudl a nsoie barrier at the bootom of your garden if it was used to power your house or clean your air.
In addition to changing teh way barriers look, one coudl also modify teh way theywork. the main mechanism for soudn reduction in traditional barriers is reflection, but new materials could be used tobuild an absorbtiev barrier (and the captural energy used to generate electrciity, for example). Or, if the noise has characteristci frequncies., layer sof Helmholt resonators could be used.
With HS2 (probably) on its way, new roads being planned, and old infrastuctures crumbling, maybe now is the time to rethink our barriers and even - who knows? - to love them.
0