Granted, most people work in office environments where they are not exposed to the same noise as an operator of welding working next to an aluminium die casting machine. Even fewer of us live near industrial premises, but that doesn’t mean most of us are not exposed to bothering noise. Before we go any further we need to make the simple distinction between sound and noise, and in particular workplace noise and environmental noise.
“Sound” is simply the sensation that the brain perceives when pressure variations in the air (sound waves generated by a vibrating source) impinges upon the ear. It is what we hear, and the intensity (and to some extent the frequency) of the sound which determines the loudness. Noise, however, is just unwanted sound. In the health and safety world this means any sound generated in the workplace of such an intensity that physiological damage can occur to the hearing system, hence it is naturally unwanted.
As I’ve said before, not many of us spend our days grinding metal in a fabrication shop. So how are we all affected by noise? Think of it this way: We have all got annoyed when the normally tolerable disturbance of a car door being slammed becomes an almighty racket because it is at four o’clock in the morning. The sound is more than certainly unwanted, therefore becomes noise. It is this oversimplified example that illustrates environmental noise and differentiates it from workplace noise. Hence, there is a need for separate control strategies.
Difficulties with environmental noise
For a start, health and safety noise issues are considerably more straightforward. There are clear and well defined noise limits that should not be exceeded without control as it is known that above these levels hearing deterioration or irreversible damage can occur. Furthermore, the effects of excessive noise exposure can be physically measured using audiometric techniques to measure the deterioration in one’s hearing. Although environmental noise can be measured by determining if sound levels generated exceed certain standards (as prescribed in legislation discussed later) the determination of what is unwanted is somewhat subjective. The nuisance factor is now introduced.
Another fundamental difference with workplace noise is that you can usually pinpoint the noise source to one or two offending pieces of plant or a particular activity. The solutions are consequently easier to implement and follow a strict hierarchy, i.e. eliminate the source of noise (modify the plant or process to design out the noise, substitute for less noisy plant, isolate the machine from the workforce, provide acoustic panelling around the source, provide quiet rest areas, and if all else fails provide hearing protection to those exposed).
It is hoped that in the UK imminent changes to the Noise at Work Regulations 2005 will remind employer’s of their duty to reduce noises at source, not relying on kitting out workers with hearing protection.
The benefits of this approach
This is not only good for all workers in a workplace but also members of the public who may live near it. That applies to workplaces within buildings and those outside, such as warehouse yards or construction sites. As the rule of thumb goes a reduction of noise by 3 decibels (or dB, the unit of sound intensity – the threshold of hearing is 0dB, the threshold of pain is 140dB) sees the intensity experienced by a person halved. That is good news when you consider the other rule of thumb: noise intensity is reduced by 3dB (seeing a reduction half) every two metres distant from the source (assuming a point source).
So wait a minute! Taking all this into consideration, regardless of new workplace legislation, surely members of the public living near a “noisy” workplace have nothing to complain about? Well it isn’t the hearing damage side of the noise that is the problem, it is the nuisance value. Sound at even barely audible intensity level is considered as noise depending on what time it is heard, the duration, the location, and other factors such as the receptor (e.g. a hospital or above a factory unit).
There is no such solution to environmental noise, which can arise from planes, cars (different makes), other vehicles, the quality of the road, the activities of neighbours. These all compound the acoustics of the surrounding environment, e.g. road quality, reflections/channelling from neighbouring buildings. It is a big old problem and affects 20% of us everyday.
In England and Wales during the period 2003/2004 there were 299,408 noise complaints made to Local Authorities (the enforcing authority for environmental noise, i.e. noise heard outside the workplace). Heading the league of shame are complaints arising from domestic premises which accounted for 73.7% of complaints. Complaints from industrial sites, commercial/leisure premises, construction/demolition sites and vehicles/equipment on the street comprise 3.4%, 14.5%, 4.1% and 4.2% of complaints received respectively. Noise complaints from road, air and rail traffic are less than 2% of all complaints. A lot of complaints means there is a lot of legislation aimed at controlling sources of environmental noise, but as touched on above this is not as straightforward as workplace noise issues.
Neighbourhood and ambient noise
When considering controlling environmental noise it is important (and easier) to make two distinctions in the types of noise, these being:
- ambient noise
The reason for this is that they are managed in different ways.
Before considering each of these aspects further, however, let’s quickly introduce the concept of nuisance. The term nuisance is commonly defined as the unreasonable interference with a persons use or enjoyment of their land or some right in connection with their land. When it comes to environmental noise that could, certainly in civil law courts, mean both neighbourhood and ambient noise. In common law, nuisances such as noise arising from premises are the main focus and is addressed in the Environmental Protection Act (EPA) 1990, Section 79. The Noise and Statutory Nuisance Act 1993 amended EPA to include noise in the street emitted from or caused by a vehicle, machinery or equipment as a statutory nuisance.
We are talking about sources such as car radios, revving cars, car alarms and roadworks. The enforcing authority for nuisance noise is the local authority (LA) who has the power to serve an abatement notice requiring abatement of the noise or prohibiting/restricting occurrence or recurrence. Failure of a company to comply with the conditions of the abatement notice, assuming they did not successfully appeal within 21 days, can result in a summary conviction of £20,000.
With the exception of street noise, neighbourhood noise is not legally defined as a statutory nuisance, although it undeniably is a nuisance. This is primarily noise generated from domestic premises and complained about by the public to the LAs. The principal legislation is the Noise Act 1996. This act defines night time noise as any noise experienced at the complainant’s residence exceeding a permitted level (10dB(A) above background level, typically 25dB(A) between 11 p.m. and 7 a.m).
Once a complaint has been made the LA has a duty to investigate the source of the noise. If they determine that noise levels experienced by the complainant are excessive, and there is no requirement to measure this, then a warning notice can be issued to the responsible person. If the noise continues, the responsible person is liable to a fine of up to £1,000 or a fixed penalty notice of £100. Amendments made under the Anti-social Behaviour Act 2003 have clarified the matters of issuing fixed penalties. Under certain circumstances, if the noise continues, the dwelling where the noise is generated can be entered by the LA and any offending equipment seized and removed. The aforementioned Noise and Statutory Nuisance Act 1993 also brings in restrictions for using loudspeakers and gives LAs certain rights for entering premises to disable audible intruder alarms (although this has not been brought into force).
So that’s neighbourhood noise. Ambient noise, on the other hand, is the same unwanted sound, this time created by traffic (road, rail and air) and from industrial sites. We have already discussed the role of the EPA 1990 in controlling noise from industrial premises. The Control of Pollution Act 1974 (COPA) is aimed at noise pollution (yet another term for what we are referring to as environmental noise) from construction sites, and allows local authorities to issue notices to construction works undertakers, imposing conditions that need to be complied with during the extent of the construction works, or at least those works that generate excessive noise (no limits are not prescribed however).
An undertaker can apply in advance for consent before the works are commenced and again conditions will be imposed. If, for whatever reason, construction works generating noise are not managed by COPA requirements, the occupier of premises exposed to noise can still force the LA to investigate the situation as a statutory nuisance under EPA 90. Industrial sites (or installations as they are known under the following legislation) requiring a permit under the Integrated Pollution Prevention and Control Regulations 2000 (IPPC) are required to apply best available techniques (BAT) to control noise as this is considered as a source of pollution.
Controlling traffic noise
Relatively simple then for industrial sites, but not so for dealing with traffic noise due to the variety of noise generating sources and the transient, often random, nature of traffic movement. Again, it is a fragmented approach to controlling traffic noise. There is legislation specifically for motor vehicles and motor cycles limiting the noise generated from engines and exhausts of motor vehicles manufactured after 1 October 1996. The Road Vehicles (Construction and Use) Regulations 1986 make it an offence to use a motor vehicle in such as way as to cause excessive noise.
This includes a restriction on when a horn can be sounded (between 7 a.m. and 11.30 p.m.), requirements for car alarms (five minute cut out required) and the permitted noise generated by vehicles tyres on a road surface. For aircraft there are similar controls on the noise generated by different types of aircraft. However, the main legislation for air travel, Civil Aviation Act 1982, specifies both day and night time permitted noise levels at the various airports around the UK. This legislation also limits the amount of flights allowed in and out of a particular airport with definite flight restrictions during the night. Rules of Air and Air Traffic Control Regulations state that planes are not permitted to fly over populated areas below the height of 1,500 feet above the highest fixed object.
Landing and take off routes are dependent on local air traffic control procedures as are the rate of height gain/loss and turning routes.
There is also legislation to be considered during development. For example, the Land Compensation Act 1973 enables property owners to claim a grant from the LA to provide noise insulation if their property is within 300 metres of a new or significantly improved road, and the resultant noise levels experienced increases by at least 1dB(A) to a prescribed level of 68dB(A). This does not apply for re-routing increasing traffic flow along existing roads. There is similar legislation (Noise Insulation (Railways and Other Guided Transport Systems) Regulations 1996) for rail noise.
Any new developments, whether they are dwellings, industrial sites, or airports, require planning permission under the Town and Country Planning Act 1990. Noise is an aspect to be considered at the planning stage, therefore the building of developments that will result in excessive noise being generated or exposed to existing noise sources should have been considered and dismissed or special controls introduced to minimise exposure.
Larger developments will often require an environmental impact assessment where noise will be an issue. There is a British Standard (BS 4142) often used in planning processes for determining increased noise from a proposed industrial premises being built near residential property. It is therefore hoped that such measures will mean that new housing will not be built near busy roads, under flight paths or adjacent to factories, but with demand outstripping availability on houses and with finite land to build on, there can be no guarantees. In such an event there will be an over-reliance on acoustic fencing and use of noise insulating building materials, hardly addressing the problems at source.
The END – Environmental Noise Directive
As can be seen from the paragraphs above, environmental noise is a subject, although taken seriously, that is approached in a piecemeal fashion, with individual sources of noise being the focus of control and enforcement. This should all change with the European Commission Directive relating to the Assessment and Management of Environmental Noise (the Environmental Noise Directive (END)), covering noise from road, rail and air traffic and industry, but focussing on those being exposed. Let’s not forget that a person’s dwelling includes outdoor areas such as the garden where noise insulating materials would not be effective.
The directive, which came into effect in July 2002, requires member states to establish common methods for measuring and assessing environmental noise, as well as informing the general public on environmental noise and its effects. Most interestingly it requires Member States to designate authorities (LAs in the UK) to map noise levels in local areas and develop action plans for reducing high noises to lower levels. The initial targets are urban agglomerations with more than 250,000 inhabitants (maps before 30 June 2007, whereas the plans will have another year for completion) and later, agglomerations with a population of more than 100,000 as well as major roads, railways and airports (2012-2013). So far, in the UK only, a noise map for the London Boroughs has been prepared.
Further progress is likely to be slow as noise mapping is a time consuming affair due in large part to the number and size of the populated area plus the fact that mapping involves complex computer modeling and physical measurement (this is a specialist activity with a limited pool of specialists out there). But once they are done life should improve for those thousands of sufferers who will no longer have to suffer in silence, as local populations will be consulted when drawing up action plans.
Such a bold move should see the harmonisation of the approach to minimising exposure to environmental noises across Europe. A lot will also have to do with the setting of environmental noise limits, which is not prescribed in the legislation, and will have to be set by the member states. This will hopefully unify the various permitted noise levels in the variety of legislation. It should, however, be borne in mind that the World Health Organisation (WHO) recommend a level of 30dB(A), averaged over a reference period, for undisturbed sleep, and during the day a level of 50dB(A) is recommended because above this persons can become “moderately annoyed”!
Published: 10th Mar 2005 in AWE International