THE IMPORTANCE OF CONTROLLING SOUND
If left uncontrolled, excess sound can become a real problem, particularly in housing, education and healthcare facilities. As aforementioned, the effects of excess noise extend far beyond just hearing damage and can even manifest in mental and physical ailments. As such, it is essential that those designing and specifying buildings do all they can to pre-empt such issues and create harmonious, sound-controlled environments. Here are some of the main problems, which can be linked to exposure of excess noise pollution:
HEARING LOSS
When overexposure to noise occurs for a prolonged period, sound energy causes the hair cells in the ear to become damaged.
The primary consequence of such excess noise pollution is hearing loss. Long-term exposure to noise continuously between 85-90 dB can lead to progressive hearing loss [3 – British Medical Bulletin December 2003].
At this point, the only remedies on offer to those affected are permanent hearing aids.
MENTAL HEALTH
Excess noise pollution can be a key driver of stress, which in turn, can have negative effects on an individual’s mental wellbeing. Studies link excess noise to increased levels of irritability, nervousness, irrationality, as well as contributing to occupational stress [4].
What’s more, as excess noise can adversely affect workplace concentration and productivity, it can begin to affect in-work competency, which can undermine an individual’s professional self-confidence.
Excess levels of noise can also increase the likelihood of incidents as performance in tasks demanding continuous attention (safety critical tasks) may be affected by noise distraction.
CARDIOVASCULAR RISK
According to the HTM 08-01 “Good acoustic conditions improve patient privacy and dignity, and promote essential sleep patterns” [1].
This is because high noise levels are known to increase an individual’s pulse rate, causing the constriction of blood vessels. In turn, this makes a person far more vulnerable to heart problems, or ailments related to high blood pressure.
SPEECH INTELLIGIBILITY
It might go without saying, but it’s far harder to communicate effectively in loud environments than it is in quieter ones. According to the WHO, ‘speech in relaxed conversation is 100% intelligible in background noise levels of about 35 dBA, and can be understood fairly well in background levels of 45 dBA [5].’
Unfortunately, persistent airborne and impact noise means that even office environments often now exceed these levels. As such, excess noise is affecting the speech intelligibility of many people, whether they know it or not. In future years, the issue will only worsen as people become older and their hearing begins to deteriorate.
POOR SLEEP
Potentially the biggest concern is excess noise’s impact on our ability to sleep. Anyone who has ever lived in a noisy neighbourhood will be able to testify how hard it is to sleep when there’s unwanted noise. Unfortunately, lack of sleep, especially if it becomes chronic can negatively affect the body in many ways.
Not only does it increase the likelihood of developing serious illnesses, such as diabetes, heart disease or stroke, but it can also increase hunger and make an individual more likely to shun exercise. [6].
HOW CAN WE CONTROL SOUND?
Fortunately, advances in sound insulation solutions mean that noises coming from inside, or outside of a building can now be significantly reduced. There are a number of solutions available, which can be used individually, or together, as part of a broader acoustic treatment scheme.
Acoustic flooring
The most well-suited insulation solution when dealing with impact sound, but also effective when looking to minimise airborne sound too. Acoustic flooring is specifically manufactured with high performance foam backing to enhance impact sound reduction. At Forbo, we have over 30 years of acoustic experience and industry knowledge of this specialist area, including our own accredited testing facility. We offer a range of acoustic floor covering solutions (standard EN ISO 717-2) with an impact sound reduction ranging between 14 dB and 30 dB to suit a variety of project requirements.
Forbo’s acoustic performance flooring coverings are also all classified as Class A for in-room impact sound (standard NF-S31-074), which is the highest rating possible. Acoustic flooring can not only be installed as part of a new build but also offers a good retrofit solution when it comes to improving the acoustic performance of older buildings.
Further information on the Forbo acoustic product offer can be found under ‘Examples of acoustic flooring'.
Sound insulation for walls
Can be used to reduce noise from both the inside and outside. One example, which is commonly found within new builds, is sound insulation, which is applied to the frame and finished with plasterboard. In turn, any sound that makes it through the exterior wall is absorbed by the insulation. At this point, any remaining sound which does make it past the finished wall only does so at a greatly reduced level.
Installing sound absorbing insulation into a retrofit project can be difficult. As such, there are also acoustic panels that can be applied to internal walls, as well as deflection panels.
Soundproof ceiling
Soundproof ceilings are either installed as new or retrofitted solutions by creating a new finishing layer onto an existing ceiling. Soundproof ceilings consist of two layers, with the gap between filled with an insulation, such as mineral wool.
IS IT POSSIBLE TO CONTROL SOUND DIFFERENTLY THROUGHOUT A BUILDING?
Unlike other forms of insulation, sound insulation is often needed to meet varying performance levels throughout a building. Particularly in larger facilities such as hospitals, student accommodation and care homes, different areas will require different acoustic performance.
As such, it is possible to specify different sound insulation solutions throughout, in order to create defined sound zones. In this next section we discuss some you might look to specify through different parts of a building and how you could best go about it.
Multi-Occupancy Housing
Acoustic performance is an important consideration when designing multi-occupancy housing. However, in these buildings, acoustic requirements will vary between different areas, so it’s important to utilise a wide range of sound controlling techniques. For example, within rooms it’s important to ensure that sound is insulated. Doing this helps to ensure that noisy neighbours don’t become a hindrance on other’s ability to sleep.
Conversely, in reception areas, or lobbies, it’s important to create an acoustic environment, which helps to amplify communication. To this end, many acoustic engineers will install surfaces that reflect sound and enhance speech intelligibility.
In Scotland, for example, Local authorities report that a rising number of complaints are about neighbour noise and mediation services report that around 50% of neighbour mediaiton cases are about noise disturbance.
Source: Neighbourhood noise nuisance: Scottish Government – Environment;
Care Homes
As care home occupants are usually older, it’s important to tailor acoustic performance accordingly. As such, the acoustic design of most care homes focuses on implementing solutions that improve speech intelligibility, whilst reducing unwanted vibrations.
Elevated noise levels tend to affect older people more significantly than they do younger people, particularly for those who have conditions such as dementia, which can worsen the effects of sensory changes by altering how the person perceives external stimuli, such as noise or light. Excess noise can make it difficult for the residents to understand each other, and staff members, especially if the resident is hard of hearing.
Too much noise can be overwhelming, and echoes can also cause stress and confusion. Therefore, limiting background sound is always a big priority when working on a care home. Similarly, in areas where staff/resident communication takes place, it’s important to create spaces, which reflect sound and make speech clearer. Once again, hearing loss is an issue that occurs more commonly in older people, so it’s important that extra care is taken.
Classrooms
In learning and teaching environments such as classrooms, it is essential to ensure good levels of speech intelligibility and listening comfort. Using sound insulation solutions to mask interfering noises is ideal. With this said, specifiers should also create a sense of reverb, which will help ensure that listening comfort sustains.
In such situations, specifiers must ensure that enough sound is absorbed to not impede listener comfort, whilst also making sure that too much sound is not absorbed, making it difficult to hear and be heard. Specifiers should look to use acoustic materials with sound absorbing and diffusing properties, as well as a small amount of reflection.
Sports Halls
When designing sports halls, specifiers should look for acoustic solutions that help to improve reverberation. The role of verbal communication in sports halls is less prominent than in other areas, so it is less important to guarantee a level of listening comfort.
Instead, planners should focus on creating an environment that feels full of activity and life. Often, sports halls have high ceilings, so it is normally wiser to install sound-insulation solutions on the walls instead.