Noise pollution is identified as a top environmental risk in growing cities all over the world in a recent report by the United Nations Environment Programme (UNEP). The report also states that solutions do exist and that they must be included in modern city planning. While there is no such thing as complete silence, unwanted sounds are considered noise, which is known to have a negative impact on human health and wellbeing.
According to the UNEP report, in Europe, long-term exposure to environmental noise causes 12,000 premature deaths and contributes to 48,000 new cases of ischemic heart disease every year. The growing scale of the problem caused the Regional Office for Europe of the World Health Organisation (WHO) to issue guidelines that are aimed at protecting human health from the effects of environmental noise pollution.
Where is noise generated?
The WHO looked at different levels of impact that noise may have on human life. They can range, for example, from being mildly annoying to causing sleeplessness and cardiovascular problems or serious mental health problems.
Potentially harmful noise in an urban setting can come from a large number of sources. The noise most often mentioned in built-up areas is generated by different types of traffic on the road, on railways or in the air. Other sources of noise include commercial and industrial facilities or construction. The WHO also identifies a category of leisure noise, such as sports venues or nightclubs.
Mitigating noise
Most industry sectors are well aware of noise and the problems it can cause. Modern engineering enables cars and other machinery to operate at much lower noise levels than just a few years ago. Planning permissions for new buildings have a noise element in most cases, which, if justified, can even override other planning concerns. While it is impossible to cut out all environmental noise, the right kind of measures can certainly reduce levels so that they are less annoying and definitely not harmful.
If cutting noise emissions down to more acceptable levels is not an option, professionally-installed insulation will help. Depending on the material used, insulation can reduce the amount of sound that is transferred through walls, ceilings and floors.
One very effective insulation material is stone wool. The fibres in stone wool are randomly orientated and, as sound waves try to pass through the air trapped within the fibrous structure, they get absorbed by friction as the individual fibres are made to move back and forth. In addition, the random orientation of the fibres gives rise to high tortuosity, which makes it very difficult for sound to find a path from one side to the other.
Testing the effectiveness of insulation as a sound barrier
It is easy enough to measure the noise within a space after it has been built. However, by then, remediation can be very difficult and expensive, if required. As such, it is important to accurately measure noise levels during the planning phase to ensure that the building design will deliver the required acoustic environment once constructed. This assessment provides the essential data needed to determine the appropriate levels of sound insulation that needs to be achieved within the building envelope.
Where projects utilise acoustic modelling in place of onsite environmental testing, a lack of real-world data can lead to over-engineered systems that incorporate additional mass layers. This can lead to additional problems like higher material and labour costs, more complex installations and longer build time.
The same is true of insulation products. Laboratory tests that simulate real-world scenarios give a much more accurate picture of material performance than any modelling can achieve. To provide greater support with specifying stone-wool insulation for sound control, ROCKWOOL can provide definite, reliable test data for architects and designers for the products that have been acoustically tested.
Proven performance
When Intersect Architects were asked to develop a design for Skyline, Bournemouth University’s purpose-built student accommodation on Oxford Road in the heart of busy Lansdowne, they knew that, in addition to the thermal and fire safety performance of the facade, controlling noise could be a challenge.
Intersect specified non-combustible RAINSCREEN DUO SLAB from ROCKWOOL for the ventilated facade insulation. Manufactured from stone wool, RAINSCREEN DUO SLAB is excellent at trapping sound waves and minimising vibration, making the insulation an excellent choice for external acoustic insulation.
Although at best annoying in most settings, noise can be detrimental to patient recovery in a healthcare setting. This was a major concern when the Bradford Teaching Hospitals NHS Foundation five-storey building on Smith Lane was being modernised.
Architect and lead consultant, Property Tectonics, specified insulation from ROCKWOOL. The acoustic properties of the ROCKWOOL RAINSCREEN DUO SLAB insulation help reduce urban noise transfer into the hospital. The top layer of each RAINSCREEN DUO SLAB board is manufactured at a higher density than the remainder of the board. The resulting change in acoustic impedance means that sound is reflected at the interface between the two layers.
What’s next?
Cities all over the world have started to fight back against noise pollution. It starts with monitoring noise emissions like, for example, in Paris, where an environmental group holds the Guinness World Record for having the “largest urban noise monitoring network on the planet” with 150 sensors all over the city. In London, acoustic camera technology is being used in Knightsbridge to investigate complaints from residents regarding loud supercars and motorbike engines.
As long as the world’s cities are growing, noise will present a challenge for architects and designers in many places, and insulation is one of the proven measures to meet it.
