Posted: 8th December 2021
When residential buildings are being planned and developed, noise is an important factor to consider. The design of residential buildings is governed by law to ensure occupants can go about their daily business, including relaxing and sleeping, without interruption from adjoining premises. Planning conditions can also place limits on the permissible level of external noise intrusion.
Noise isn’t simply a nuisance but is a health concern too. Continual exposure to noise has been linked to a variety of health problems, from stress and fatigue to cardiovascular disease and hearing loss.
A successful acoustic design needs to consider many different sound transmission paths. Some, such as airborne sound transmission from outside through a window or through a separating floor between flats, are easily identified and mitigated. Other transmission paths, such as transmission horizontally within a common floor slab running under a separating wall, or sound transmission through pipes, are described as flanking transmission. These are often much less obvious and may not be identified without the input of an experienced acoustic consultant. This is especially the case where residential dwellings are being formed in an existing building which may have a number of hidden flanking transmission paths.
Certain acoustic considerations are required at the planning stage, while others are required for Building Regulations approval. Some developments are more problematic than others, but typically considering the following aspects will ensure that your development complies with all acoustic regulatory requirements and achieves a good standard of acoustic amenity for future residents.
What noise is there in the local environment and how might it transmit into the property? If there are noisy commercial premises such as bars or factories nearby are these likely to cause a greater disturbance to future residents? Typically, a sound level survey is required to measure the background level in the area and an appropriate acoustic specification is issued for façade elements (windows/ventilators, etc.). What ventilation strategy is proposed for the development? Will having openable windows to avoid overheating result in excessive noise levels inside habitable rooms?
Is the site close to sources of vibration, such as train lines, that could lead to noise transmission or perceptible vibration? Carrying out vibration measurements can identify potential areas of concern at an early stage, as retrofitting mitigation to control groundborne vibration into a building is incredibly difficult to achieve, not to mention massively expensive.
Appropriate acoustic insulation is required for separating floors and walls to reduce the transmission of airborne noise between rooms and adjoining properties. The performance requirements are controlled by The Building Regulations Approved Document E. Where a residential dwelling shares a separating element with a commercial property then a higher standard of sound insulation may be required.
Effective measures should be taken to reduce impact noise. As with airborne sound insulation, the minimum performance standards are controlled by The Building Regulations.
An area which is often overlooked is Requirement E3 of The Building Regulations, which controls the amount of echo (or reverberation time) in communal areas of residential buildings. A growing problem, in part caused by the trend to ditch soft furnishings and carpets, it is important this is considered early in the development and appropriate surface finishes incorporated into the design.
The use of mechanical equipment, such as mechanical ventilation heat recovery (MVHR), mechanical extract ventilation (MEV), and air conditioning systems, can generate noise that should be controlled to prevent it from becoming a nuisance. A response to the growing need to mitigate overheating in new dwellings is to incorporate mechanical ventilation or cooling systems. However, a body of evidence shows that if the equipment is too noisy then residents will elect to not use the systems, negating their benefit.
New equipment associated with residential developments, such as air conditioning condensers and some air source heat pumps (ASHP), will normally require planning permission. This requires existing background sound levels to be measured, noise from the new equipment to be predicted to outside nearby noise-sensitive properties, and if necessary acoustic enclosures, barriers, or other noise control treatments to be designed.
Poor acoustic design, or not considering acoustic aspects early enough in the development, can cause no end of problems ranging from refusal of planning permission or onerous planning conditions, failing Building Regulations pre-completion sound insulation tests, to an inhospitable environment and complaints from future residents. Working with an acoustic specialist is crucial to ensure that your development avoids these problems. For more information, call us on 01793 766324 or send us a message.
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