Principles of noise pollution
Noise is generally considered to be unwanted sound and sound can be considered unwanted due to reasons of volume, type of noise, the time of day, or any factor making sound unpleasant or annoying. As this is often subjective noise pollution can be controversial.
Noise pollution impacts upon health and wellbeing by causing disturbances that create poor quality environments. Noise pollution in residential environments can cause physical and mental health deterioration. In the workplace and educational environments, these symptoms can accompany reduced productivity and quality of work.
Noise can also have a notable impact on the natural environment, for example noise may alter bird breeding patterns, disturb wildlife and damage sensitive ecosystems.
The majority of noise complaints in Hertfordshire are associated with domestic noise, however other significant sources include:
- entertainment noise
- industrial/commercial noise
- construction noise
- road traffic - Hertfordshire has many motorways and secondary distributor roads such as the M25, M1, A1, A414 and A10
- flight paths - Stansted and Luton airport flight paths pass over parts of Hertfordshire; both airports have significant plans for increased capacity
Household and employment growth is forecast for Hertfordshire. It is likely that noise considerations will become increasingly significant as the living and working populations increase.
The main emphasis of current noise standards and regulations is to minimise annoyance. Although defining noise pollution is often subjective, complaints are taken seriously as noise pollution intrudes upon individuals' health. This is supported by this World Health Organisation definition:
“Good health and well being require a clean and harmonious environment in which physical, physiological, social and aesthetic factors are all given their due importance. The environment should be regarded as a resource for improving living conditions and increasing well being.” (WHO 1990)
Under Part III of the Environmental Protection Act 1990 certain matters are declared to be ‘statutory nuisances’. This includes noise emitted from premises so as to be prejudicial to health or a nuisance and noise that is prejudicial to health or a nuisance and is emitted from or caused by a vehicle, machinery or equipment in a street.
Threshold of hearing
Sound is a wave motion that carries energy from one point to another through an elastic solid, liquid or gas (air). The waves are produced by a vibrating object producing pressure fluctuations. As those reach the ear, the eardrum vibrates in direct response, and these pressure fluctuations are heard as sound. For the sound to be audible, the wave frequencies must be in the range of 20 to 20,000 Hz (pulses per second). Sound pressure level is measured in decibels (dB).
In addition to potentially causing deafness, noise can also contribute to other health risks. For example, the World Health Organisation states that working in environments with high levels of industrial noise creates a greater risk of cardiovascular disease.
Noise in the built environment has the following primary sources:
- construction and demolition processes
- subsequent building operations
- domestic activities from adjoining properties (e.g. adjacent apartments, terraces)
- from adjoining noise sources (e.g. 24hr commercial operations, bars etc.)
Noise should be considered as early as is practicable at the planning/outline design stage of any development.
Construction sites can act as significant source of noise pollution and requires careful management. Construction site noise can have negative health and productivity impacts on both site workers and occupants of neighbouring buildings.
Construction noise and vibration is strongly regulated by legislation including the Control of Noise at Work Regulations 2005, the Control of Pollution Act 1974, Sections 60 & 61 and British Standard 5228 Code of practice for noise and vibration control of construction and open sites. The lower exposure action level is 80dB(A) for an equivalent 8hr working day, however, frequent causes of construction site noise are:
- heavy machinery and tools used on site
- traffic associated with transport of materials and surfacing works
- consequential traffic congestion
- construction worker raised voices, mobile phones, radios, etc
The following table lists typical sources of construction site noise:
|Plant or machine||Likely noise level dB(A)**|
|Pile drivers (traditional methods)
|Pneumatic hammers and breakers
|Shot-firing gun (cartridge tools)
|Excavators (JCBs etc)
* Short, very loud impact noises do most harm ** The first action level under the Control of Noise at Work legislation is 80 dBA.
Sound transmission in buildings and the benefits of good acoustic design
Noise transmission into dwellings from external in sources is to a large extent controlled by the planning process.
Sound transmission between buildings is controlled by implementation of Building Regulations Approved Document Part E. Building Bulletin 93 (BB93) contains the minimum requirements for acoustic conditions in schools. Good planning and design can significantly enhance the acoustic environment in buildings. Time spent in the early stages of a project is often a good investment as remedial treatment in finished buildings to improve sound insulation or the acoustic environment can be costly.
Good sound insulation generally also means good thermal performance therefore assessing acoustic and thermal performance of building fabric can be integrated for greater cost effectiveness.
There is no single solution for controlling sound transmission in buildings. Both heavy masonry and lightweight timber or steel stud building systems can have good sound insulation. Guidance can be found in Approved Document E and Robust Details Part E. Developments being assessed under BREEAM or the Home Quality Mark can gain credits for both internal and external noise levels where tested by a suitably qualified acoustician and sound insulation.
BREEAM credits are awarded based on building type and specific requirements can apply to rooms depending on use.
Home Quality Mark awards up to 2 credits for noise levels of external functional space, such as gardens or balconies, between 7am and 11pm. 1 credit is awarded below 55dB and 2 credits below 50dB. A further 2 credits are available where internal noise levels are below 35dB at all times and below 30dB in bedrooms from 11pm to 7am.
Up to 8 Home Quality Mark credits are available for sound insulation, 4 for between homes and 4 for between rooms. Between homes airborne sound insulation credits are awarded for results above 48dB, and impact sound insulation credits are awarded for results below 59dB. Between rooms airborne sound insulation should be above 43dB for any credits to be awarded.
Benefits of noise management
Actively managing and designing out noise delivers the following benefits:
- Fewer noise complaints.
- Improved health and well being benefits for building occupants including undisturbed sleep and mental wellbeing.
- Increased productivity in places of work and education.
- Less need for expensive retrofitting of acoustic insulation.
- Better quality of life.
- Reduced need for costly remedial acoustic works and legal action/business disruption.
Positioning of rooms
A - Positioning of rooms less sensitive to noise towards stairs, i.e. halls and bathrooms
B - Common stairway
A - Use of high density noise plates to dull sound transmission
B - Noise sensitive areas located away from sources of external noise, such as building services and traffic
C - Bedroom located on quiet side
D - Discontinuous building fabric to prevent structure sound transmission
The National Planning Policy Framework (NPPF) sets out the government's planning policies for England. As part of the government's commitment to achieving sustainable development, noise is part of a holistic approach to achieving, economic social and environmental gains.
Planning policies and decisions should aim to:
The governments Noise Policy Statement sets out the long term vision of government noise policy and provides clarity regarding current policies and practices to enable noise management decisions to be made.
- avoid noise from giving rise to significant adverse impacts on health and quality of life as a result of new development;
- mitigate and reduce to a minimum other adverse impacts on health and quality of life arising from noise from new developments, including through the use of conditions;
- recognise that development will often create some noise and existing business wanting to develop in continuance of their business should not have unreasonable restrictions put on them because of the changes in nearby land uses since they were established; and
- identify and protect areas of tranquillity which have remained relatively undisturbed by noise and are prized for their recreational and amenity value for this reason.