The Scottish Government

Planning Advice Note: PAN 56

Introduction

1. Noise can have a significant impact upon our health, quality of life and the environment generally. This advice note demonstrates the role of the planning system in preventing and limiting the adverse effects of noise without prejudicing investment in enterprise, development and transport. It builds on principles set out in SODD Circular 10/1999 Planning and Noise and takes account of the recommendations of the Noise Review Working Party (HMSO, 1990).

2. The Planning Advice Note (PAN);
indicates how noise issues should be handled in development plans and development control;
outlines ways of mitigating the adverse impact of noise;
provides specific guidance on noisy and noise-sensitive development;
introduces the use of noise exposure categories;
gives guidance on the use of planning conditions relating to noise.


This PAN does not aim to provide a definitive source of prescriptive guidance on noise issues. Neither is the advice intended to turn planners into experts on noise which is a highly technical and complex area best handled by noise specialists. The PAN does, however, set out the range of noise issues that planning authorities need to be aware of in formulating development plans, making decisions on planning applications and in taking enforcement action to preserve and enhance environmental quality. It will also be of assistance to developers in indicating issues related to noise likely to be taken into account in the consideration of planning applications.

3. Noise issues are referred to in a number of National Planning Policy Guidelines, notably NPPG 2 Business and Industry, NPPG 4 Land for Mineral Working, NPPG 6 Renewable Energy and NPPG 8 Town Centres and Retailing. It also features in Planning Advice Notes. PAN 50 Annex sets out good practice for the control of noise at surface mineral workings. PAN 51 deals with Planning and Environmental Protection regimes and includes references to statutory nuisance, including noise, in paragraphs 7.1 to 7.8 of its annex.

4. Technical terms are widely used in measuring and assessing noise. Some explanation of these appears in the text and a glossary has been provided.

general principles

5. The planning system has an important role to play in preventing and limiting noise pollution. The redevelopment of brownfield sites for housing, a concentration of transport on existing transport corridors and the increasing emphasis upon mixed-use developments are likely to make noise issues an increasingly important consideration in planning decisions. Although the planning system cannot tackle existing noise problems directly, it has the task of guiding development to the most suitable locations and in regulating the layout and design of new development. The noise implications of development can be a material consideration in determining applications for planning permission.

6. Activities that generate high levels of noise can be difficult to reconcile with noise sensitive land uses like housing, hospitals or schools. Planning authorities can do two things. Noise-sensitive developments can be separated from major noise sources or orientated and designed to minimise the impact of noise. New development can also be sited away from noise-sensitive land uses. Development plans provide the policy framework within which these issues can be considered but careful attention will also need to be paid to noise issues in determining applications for planning permission. Where it is not possible or desirable to separate noisy land uses from uses sensitive to noise or to negotiate design solutions that mitigate the adverse affects of noise, planning authorities can then consider measures to control noise levels through conditions or, in exceptional circumstances, planning agreements.

7. The prediction, measurement and assessment of noise is a complex professional task requiring specialist knowledge and expertise. Planning authorities will need to work closely with environmental health officers, and others with expertise in acoustics, in preparing development plans, during pre-application discussions and when determining applications for planning permission which raise noise issues.

noise policies in development plans

8. Development plans can include policies which help ensure that developments that are likely to generate significant amounts of noise are not positioned close to noise sensitive developments such as existing or proposed housing development. In certain areas, for example, in the vicinity of airports, special policies relating to noise may need to be included in local plans. The purpose of such policies is to indicate the range of uses which are likely to be permitted in an area affected by existing or potentially high levels of noise as well as the noise mitigation measures the planning authority will seek to apply. Planning authorities can also adopt policies to discourage noisy development in areas that have been relatively undisturbed by noise nuisance and are prized for their environmental, historic, recreational or amenity value. More detailed development control policies, such as those relating to the design and layout of new housing, can also be formulated to take account of noise issues.

9. Providing certainty is a key task for local plans and so they should incorporate policies that reassure local communities that their amenity will not be undermined by new noisy development. At the same time, developers should reasonably expect that suitable sites will be allocated for activities essential for economic development and employment, even though they involve noisy processes or require extended hours of operation.

10. Planning authorities should also seek to involve those likely to be directly affected by planning policies which address the land use implications of noise. As noise emissions may change significantly over relatively short periods of time proposals maps should not normally show detailed noise contours. Plans can, however, include area specific policies that indicate the nature of development likely to be permitted in a particular area and the conditions or limitations that may need to be applied.

considering noise in development control

Assessing Noise

11. The noise implications of proposed development will not always be apparent immediately on receipt of a planning application. Effective treatment of noise often depends upon being able to address issues early and planning authorities are encouraged to consult with environmental health officers upon receipt of any application that is likely to raise noise issues. Authorities are also reminded that development proposals that these may require to be advertised as 'bad neighbour' development in terms of the Town and Country Planning (General Development Procedure)(Scotland) Order 1992.


Measuring Noise

Noise is measured in decibels (dB), where zero dB is the lower limit of audibility and 140 dB is the level at which physical pain in the ear may be felt. Individual sensitivity to noise is highly subjective and is affected by a range of factors. As these can include non-acoustic matters, such as attitude to the noise source, sensitivity may not always relate directly to the level of noise.

Decibel (dB): a unit derived from the logarithm of the ratio between the value of a quantity and a reference value. It is used to describe the level of many different quantities, including noise.

dB(A): decibels measured on a sound level meter incorporating a frequency weighting (A weighting) which differentiates between sounds of different frequency (pitch) in a similar way to the human ear. Measurements in dB(A) broadly agree with people's assessment of loudness. For noise of a similar character, a change of 3 dB(A) is the minimum perceptible under normal conditions, and a change of 10 dB(A) corresponds roughly to halving or doubling the loudness of a sound.

Ambient Noise is the totally encompassing sound (from near and far) in a given situation at a given time.

Existing noise levels can be expressed as LA90,T. The A weighted noise level exceeded for 90% of the give time interval T. They are usually quoted to the nearest whole number of decibels.

Noise can have a considerable impact upon our quality of lives. Internal levels less than 35dB(A) are recommended to preserve the restorative process of sleep. At a distance of 1 metre from the speaker, relaxed conversation occurs at a noise level of approximately 56dB(A) and normal and raised voice levels of approximately 66Db(A) and 72dB(A) respectively1.

12. Applications for planning permission which raises issues of noise generation, should be examined in terms of the:
level of noise that is likely to be generated;
character of the noise;
way in which it is likely to be transmitted; and
time periods involved.


Existing noise levels and the sensitivity of existing uses to noise should also be taken into account. Sudden impulses (e.g. hammering noises), noise with a repeating pulse or rhythm, noise which is likely to cause vibration, irregular noise or noise which contains a distinguishable tone will require special consideration and expert advice will be particularly important. Consideration of these more complex types of noise may merit the use of specialist indices such as noise rating (NR) curves.

13. Creeping ambient noise can undermine attempts to control noise pollution. Ambient noise levels can increase with cumulative small-scale development and the intensification of existing land uses, which themselves are not considered significant in terms of the noise they generate. Although often outwith the direct control of the planning system, planning authorities should be aware of the cumulative effect of small scale development on ambient noise levels when considering development proposals and formulating development plan policies.

Noise Impact Assessment

14. Planning authorities' consideration of planning applications that raise significant noise issues will be greatly assisted by a noise impact assessment. These can be used to show whether a noise problem is likely to occur, demonstrate its implications and help identify measures for its effective control or mitigation. Noise impact should be assessed with reference to the character of the surrounding area (including existing buildings and landform) and will enable planning authorities to determine accurately the noise implications of proposed development upon local communities and the environment generally. It may form part of a more general Environmental Impact Assessment (see paragraph 65)

Noise Impact Assessment

Noise impact assessments should seek to:
measure or predict and describe noise levels (including traffic noise)
(i) to be generated by the proposed development; or

(ii) that the proposed development is to be subjected to.

establish criteria for assessing the impact of noise on its surroundings.
outline measures available to reduce noise impact to acceptable levels.


Before carrying out noise impact assessment planning authorities should agree with the applicant representative levels (and the way in which this will be assessed) of existing noise that the proposed development will be assessed against. It will also be useful for applicants if authorities indicate the noise levels that they consider acceptable in the context of the proposed development.

Footnote 1 Environmental Health Criterion 12 - Noise (World Health Organisation, 1980)

mitigating noise impact

15. There are various ways to control noise or limit people's exposure to it through design. These design measures should be the minimum necessary and may include one or more of the following:

• Engineering and building design:
  
  reducing noise at point of generation, for example by using quiet machines and quiet methods of working;
  
  containing noise, for example by insulating buildings which house machinery and providing purpose-built barriers around a site; and
  
  protecting noise-sensitive buildings and areas, for example by improving sound insulation in these buildings and screening them with purpose-designed acoustic barriers;
  
• Layout design: for example, adequate distance between source and noise-sensitive building or area; screening by natural barriers, other buildings, or non-critical rooms (e.g. garages or bathrooms) or elevations of a building;
  
• Management design: for example, specifying an acceptable noise-limit, limiting operating time of source or restricting activities allowed on the site.
  
  Examples of good practice in relation to the mitigation of noise as far as it affects the design and layout of residential development is contained within Sound Control for Homes (BRE/CIRIA, 1993, ISBN 085125-559-0).

16. Early discussion with the applicant and with noise experts about design measures is desirable and may enable them to be incorporated before the application is submitted. Addressing noise issues early in the development process is usually a good deal cheaper and less disruptive than remedial action in a completed project. Strategic decisions relating to site planning, built form and materials can all dramatically influence noise control matters without having cost implications providing these choices are exercised early enough. Alternatively, planning authorities can ensure that such measures are introduced through negotiation or via planning conditions. Limiting the adverse effects of noise by engineering and layout design is usually to be preferred. Whilst successful in controlling noise, planning conditions that restrict hours of operation could undermine the economic efficiency and operational capacity of a business or enterprise over the longer term.

noisy development

17. Planning authorities should generally aim to ensure that development does not cause unacceptable noise disturbance. They should also make appropriate provision for development necessary for the creation of jobs and the construction and improvement of essential infrastructure even though it may generate noise. Areas vary in character and levels of noise that are acceptable in one location may not be acceptable in another.

18. Advice on some of the major noise sources is given below. Advice on the control of noise from mineral working sites is provided separately in PAN 50 Annex A: The control of noise at surface mineral workings.

Road Traffic Noise

19. For the upgrading of existing roads it will normally be sufficient to base assessments on the current measured noise level. When considering proposals for the development or improvement of major roads, forecast noise levels (e.g. over the next 15 years) can be ascertained with the help of the roads authority. In some cases, roads authorities may have prepared predictions of the effects of traffic noise for the purposes of the Noise Insulation (Scotland) Regulations 1975 (as amended). The method set out in Calculation of Road Traffic Noise (DoT, Welsh Office 1988) for predicting road traffic noise will depend upon accurate data on traffic flow being available. Further information on assessing road traffic noise is available within the Design Manual for Roads and Bridges (DoT, 1994)

20. Heavy goods traffic generated by commercial, industrial and other major developments can cause particular noise and disturbance problems. Impact assessments in such cases should take account of the features that can contribute to the level, tone and variation in noise and disturbance, the pattern of vehicle movements and the configuration of the road system concerned.

21. Research undertaken by the Transport Research Laboratory indicates that structural damage of buildings through road traffic vibration is generally unlikely. If vibration remains a concern however, advice on acceptable levels can be found in BS 6472 Guide to evaluation of human exposure to vibrations in buildings, and advice on levels that may result in damage to structures in BRE Digest 353 Damage to structures from ground borne vibration.

Noise from Railways

22. Railway noise can come from a variety of sources in addition to operational railway lines. Noise from station activities, freight distribution depots etc. should be treated in the same way as noise from industrial or commercial sources. Railway operators should have details of current traffic flows, and in some cases noise levels. These should be submitted along with any application likely to raise noise issues. The method set out in Calculation of Railway Noise (DoT, Welsh Office 1995) will also be of assistance in predicting rail traffic noise.

23. The likelihood of significant ground-borne vibration will depend on the nature of the terrain and types of train. The possibility of vibration and deflected noise caused by trains running in tunnels should not be overlooked. Advice on acceptable levels of vibration can be found in BS 6472 Guide to evaluation of human exposure to vibrations in buildings.

Noise from Civil Aerodromes

24. Noise from aerodromes is likely to include activities such as engine testing and ground movements as well as aircraft landing and taking off. For major aerodromes, noise (NNI) contours were produced for many years to aid development control although it is now accepted that LAeq (see glossary) is the most appropriate unit of measurement. The introduction of quieter types of aircraft, combined with attempts to attract a greater number of these, has meant that noise contours have shrunk over the last few years. However, continued growth in the number of aircraft movements at the major airports may mean that these may expand again at some stage in the future. Ideally, daytime noise contours should be over the period 07.00-23.00. For appropriate needs, noise contour maps for the major Scottish airports Glasgow, Edinburgh and Aberdeen are available from Scottish Airports Limited, St Andrew's Drive, Glasgow Airport, Paisley, PA3 2SW. These are usually updated every five years and forecasts are provided. It is not recommended, however, that forecast Leq contours be used as a basis for development control. For other airports information will be available from the local management. Where daytime noise contours expressed in Leq are not available, authorities should approach the management to secure early compilation of contours.

25. Where land is subject to significant levels of aircraft noise, or is likely to become so planning authorities should seek the co-operation of aerodrome management in reaching appropriate forecasts of air traffic and its effect on noise contours. The objective will be to achieve a clear and stable pattern of constraints against which development control decisions can be made.

26. Beyond the extremities of the published contours, noise may still be heard near arrival and departure routes. Final approach routes are predetermined by the orientation of the runway and by wind direction. Intermediate approach routes may vary significantly depending upon the requirement for safe sequencing of incoming traffic and on locally agreed procedures designed to minimise noise resulting from the use of thrust management techniques. The use of these routes may change over time because of changes in aircraft mix and operations. For further information, planning authorities should consult the air traffic controllers at their local airport.
27. An Environmental Impact Assessment is always required for proposals to develop an airport with a basic runway length of 2100 metres or more and may be required for other proposals to develop airfields. Further guidance is contained within SODD Circular 13/1998 (shortly to be updated). In any event, where a proposal will affect the capacity of a major airport there will be a need to prepare or revise the forecast noise contours and evaluate the resulting noise climate.

Noise from Military Aerodromes

28. When determining applications for this type of development planning authorities should take account of the differences between civil and military operations. Military jets can generate very high noise levels, particularly during take off, and occasionally the effectiveness of noise abatement flight procedures normally adopted may be limited by operational requirements. Changes in aircraft type and number of movements may also occur over a short period, resulting in unpredictable changes in noise levels. However, military flying is usually concentrated into weekday working hours when background noise and daytime activity render aircraft noise less intrusive. Where disturbance caused by military aircraft is likely to occur from take-off and landing outwith the boundaries of the planning authorities area affected authority's should be consulted.

29. For aerodromes where a Ministry of Defence (MoD) noise insulation scheme has been introduced, authorities will already hold a MoD map showing LAeq,T contours. Since February 1994 these have been based upon a 16-hour period as is generally used at civil aerodromes. Other information and advice may be obtained from the Ministry of Defence through the aerodrome commander or MoD land agent.

Helicopter and Heliport Noise

30. When determining a planning application for a heliport the predicted noise should not be assessed in isolation. Account should be taken of local circumstances, including the existing level of noise disturbance in the area surrounding the site and factors such as whether the area is already exposed to noise from fixed wing aircraft.

31. Helicopter noise has different characteristics from that of fixed wing aircraft and is often regarded as more intrusive and annoying by the public, especially when helicopters spend time hovering overhead.

32. Helicopter routes may be established over cities and near aerodromes, although often their use will not be mandatory or, due to manoeuvrability of helicopters, adhered to. Planning applications for heliports should be accompanied by information about the proposed take-off/landing flight paths, and air traffic routes where appropriate. Preferably, these paths should have been discussed and agreed in principle with National Air Traffic Services (NATS) beforehand. Where such information does not accompany the application, but is considered necessary, the planning authority should request it and suggest that the applicant consults with NATS. While it is appropriate that planning authorities should request information about proposed flight routes, they should appreciate that the planning system is concerned with land use; not the use of air space. In particular, planning conditions relating to flight routes are likely to be inappropriate.

33. Similarly, Civil Aviation Authority jurisdiction is limited in the extent to which helicopter flights can be controlled. The CAA's regulatory functions relate, essentially, to economic or safety regulation and not to amenity matters. Increased use of helicopters has led to movements from the gardens of large private houses and from commercial premises, such as offices and hotels. Helicopter tours over Scotland's major cities and areas of landscape value are also becoming more prevalent. For safety reasons, helicopters may only operate from elevated sites if given special approval by the Civil Aviation Authority. All these movements can cause disturbance locally but may be incidental or ancillary to the principal use of the land or of a temporary nature and so do not require planning permission. Voluntary agreements may be an effective way of limiting disturbance in these cases.

Noise from Windfarms

34. There are two sources of noise from wind turbines; the mechanical noise from the turbines and the aerodynamic noise from the blades. Mechanical noise can be reduced through engineering design. Aerodynamic noise depends upon rotor speed which varies with wind speed. Noise from the wind normally increases at a faster rate than the turbine noise. This means that aerodynamic noise of wind turbines is generally greatest at low speeds. However, in sheltered positions where "wind shadow" occurs, such as in leeward valleys, existing noise levels may remain low when turbines on adjacent higher ground are operating at higher wind speeds. Equally, noise levels at properties affected by prevailing winds may well be greater than in other areas. Good acoustical design and siting of turbines is essential to ensure there is no significant increase in ambient noise levels as they affect the environment and any nearby noise-sensitive property.

Noisy Industrial Development

35. Due to its variable character industrial noise is difficult to assess. However, BS 4142 Method for rating industrial noise affecting mixed residential and industrial areas promotes a method for assessing whether industrial noise is likely to give rise to complaints from people living nearby. Whilst a useful guide, BS4142 should not be solely relied upon to accurately establish the impact of industrial development in terms of noise.

36. The standard uses comparisons between the measured background levels of a location and the anticipated noise levels from proposed activities. BS4142 suggests that, in general, a difference of 5dB is likely to be marginal, whilst an increase in 10dB will be likely to give rise to complaints. Tonal or impulsive characteristics are likely to increase the likelihood of complaints and this is taken into account by the 'rating level' defined in BS 4142. This 'rating level' should be used when setting the level of noise that can be permitted. Since background noise levels vary throughout a 24 hour period it will usually be necessary to assess the acceptability of noise levels for separate periods (e.g. day, evening, night and weekend) chosen to suit the hours of operation of the proposed development. In applying BS4142 authorities should also bear in mind the significance of absolute levels. In some cases any increase over existing threshold levels will be unacceptable. When setting noise limits expressed in terms of LAeq, NR curves (see, for example, BS 5720 Code of practice for mechanical ventilation and air conditioning in buildings) etc. consideration should be given to the nature of the existing noise climate.

37. General guidance on acceptable noise levels within buildings can be found in BS 8233 Sound insulation and noise reduction for buildings. Planning authorities should also take into account the noise that may result from traffic generated by new industrial developments.

Noise from Commercial Developments

38. Commercial developments such as restaurants, hot food take-aways, night-clubs, pubs and cinemas pose particular difficulties, not least because associated activities are often at their peak in the evening and late at night. For this type of development, vocal noise and noise resulting from amplified music can create noise disturbance when heard by the residents of adjacent properties; even at low levels. Authorities may wish to consider attaching conditions to any consent for such development in order to safeguard residential amenity. Advice on the use of conditions is provided in paragraphs 59-62 and in Annex 3.

39. Planning authorities should not only consider the noise that is generated within the premises but also the attendant problems of noise that may be made by customers and related vehicles in the vicinity; particularly in residential areas. Traffic noise resulting from deliveries to major retail developments and changes between shifts are particularly significant. Where noise of this nature is likely to cause disturbance during unsociable hours authorities may wish to consider attaching conditions to regulate it.

Construction Site Noise

40. Whilst planning conditions can be used to limit noise from temporary construction sites it is most effectively controlled by means of the of the Control of Pollution Act 1974 (see Annex 4). Notice can be served in advance of works and site conditions set to control activities.

41. Detailed guidance on noise issues relating to construction sites can be found in BS 5228 Noise control on construction and open sites. In particular, Part 1, "Code of Practice for basic information and procedures for noise control" will be useful because as well as giving general advice, it describes a method for predicting noise from construction sites.

Noise from Recreational and Sporting Activities

42. The impact of noise from sport, recreation and entertainment will often depend on frequency of use and the design of facilities. For these activities (which include open-air music concerts), the planning authority will have to take account of how frequently the noise will be generated and how disturbing it will be. Partially open buildings such as stadia may not be in frequent use. Depending on local circumstances and public opinion, it may be reasonable to permit higher noise levels than for other types of development, subject to a limit on the hours of use, and the control of noise (including public address systems) during unsociable hours. A number of sports activities are the subject of Codes of Practice, and further details on these can be found in Annex 4. Some noisy activities may not require specific planning permission provided that they occur on a temporary basis. However, this permission may be withdrawn by making a direction under Article 4 of the Town and Country Planning (General Permitted Development) (Scotland) Order 1992. Additional advice on noise in relation to recreational and sporting activities can be found in NPPG 11 Sport, Physical Recreation and Open Space. Further guidance on noise at music concerts can be found within the Noise Council Code of practice on environmental noise control at concerts (The Noise Council) 1995.

Noise from Landfill Sites

43. The main sources of noise will be from vehicular movements, tipping operations, and site plant. Waste management licence conditions generally set limits to the amount of waste, frequency of deliveries, and hours of operation; and prescribe screening requirements. These will have indirect effects on the amount of noise generated, but site licence conditions can also relate specifically to noise control in the interests of protecting local amenity. They will be particularly relevant in sites worked with the benefit of a Certificate of Lawful Use or a planning permission not subject to a noise condition. Planning authorities, the Scottish Environment Protection Agency and local Environmental Health Departments should consult closely at an early stage when considering the need for specific noise controls to be imposed by suitable conditions (see paragraph 59-62) in any planning permission or in the subsequent site licence.

44. Licensing conditions or planning conditions designed to protect amenity might therefore relate to hours of working; the number and/or capacity of vehicles using the site and their points of ingress and egress; and the provision of acoustic screening. Useful information on predicting this type of noise will be found in BS 5228 Noise control on construction and open sites. General guidance can be found in NPPG 10 Planning and Waste Management, and many aspects of good practice outlined in PAN 50 Annex A, Control of noise at surface mineral workings, will also apply.

noise-sensitive development

General

45. As indicated in SODD Circular 10/1999 Planning and Noise housing, hospitals, educational establishments, offices and some livestock farms should generally be regarded as noise-sensitive land uses. Authorities may also wish to include other developments or uses (such as places of recreation) within this definition, depending on local circumstances and priorities. This should be explained in the development plan.

46. The juxtaposition of incompatible uses can cause problems for the occupiers of both the new and existing development. For example, where a residential development is proposed in the vicinity of existing industrial uses, the expectations of new residents may exceed the standards applied by the planning authority and which may give rise to local pressure to curtail the existing use. Planning authorities should, therefore, try as a matter of good practice to keep a suitable distance between noise sensitive development and established businesses that generate noise.

47. In determining applications for development that will be exposed to an existing noise source, authorities will need to consider both the likely level of noise exposure at the time of the application and any increase that may reasonably be expected in the foreseeable future. The extent to which it is possible to mitigate the adverse effects of noise (see paragraph 15) will also be a consideration. In order to accurately establish current and expected noise levels planning authorities may consider requesting that applications are submitted in detailed format rather than in outline. Authorities will also wish to bear in mind that while there will be sites where noise is significantly lower at night than during the day, other sites may be subjected to night-time noise from traffic at a level which is little below the day-time level. Night-time deliveries and changes between shifts can be particularly significant in this respect. These sites require special consideration.

48. Planning authorities should consider carefully in each case whether proposals for new noise-sensitive development would be incompatible with existing noisy activities. Sources of intermittent or tonal noise e.g. noise from industrial development, will require individual assessment and noise impact will need to be assessed against existing noise levels, using the most appropriate parameters, and in terms of local circumstances and possible changes in noise climate.

49. Where replacement schools, clinics, and other community facilities are needed to serve the existing population in noisy areas, expert advice should be sought on the feasibility of noise insulation.

Residential Development and Transport Noise

50. This advice note suggests the use of Noise Exposure Categories (NECs) to help planning authorities determine applications for residential development on sites subjected to noise from road, rail, air, and "mixed" transportation noise. The noise category method does not take industrial noise into account. When assessing a proposal for residential development, planning authorities can determine into which category the proposed site falls, taking account of average day and night-time noise levels, as well as a maximum upper night time value. The categories identify the need for development proposals to address noise issues and put forward recommended standards for noise exposure to which new housing development must comply through, for example, the introduction of noise mitigation measures.

51. For category A sites noise is unlikely to be a determining factor, while for Category D sites refusal of planning permission is likely to be the most appropriate solution. Categories B and C deal with situations where noise mitigation measures may make development acceptable. The table below explains the categories in more detail. The NECs will carry more weight if incorporated into development briefs etc. and adopted as supplementary planning guidance. Annex 1 sets out the approach in more detail and puts forward a range of recommended values.

A Noise need not be considered as a determining factor in granting planning permission, although the noise level at the high end of the category should not be regarded as desirable.
B Noise should be taken into account when determining planning applications and, where appropriate, conditions imposed to ensure an adequate level of protection against noise. For proposed development subject to the high end of the category a Noise Impact Assessment will assist authorities in identifying appropriate noise mitigation measures.
C Planning permission should not normally be granted. Based upon the evidence contained within a Noise Impact Assessment, however, it may be possible to grant permission subject to measures that ensure an adequate level of protection against noise.
D Planning permission should generally be refused.

An adequate level of protection should normally be interpreted to mean commensurate with Category A levels. Where development is desirable in terms of the overall planning strategy for the area but where local circumstances or excessive costs prohibit the effective mitigation of noise commensurate with category A levels consideration may need to be given to relaxing noise standards. In such cases, internal noise levels within individual living apartments should be less than 45dB(A) during the day and 35dB(A) during the night. Levels should be predicted using appropriate time periods and the LAeq parameter.

52. It is important to note that the Noise Exposure Categories apply only where consideration is being given to introducing new housing development into an area with an existing transport noise source and not in the reverse situation. The statutory planning system can be used to impose conditions to protect incoming residential development from an existing transport noise source. However, planning conditions cannot normally be applied to ensure transport operators offer noise protection measures to existing dwellings that will be affected by a proposed noise source. The differing attitude and sensitivity towards noise between those who choose to live in a relatively noisy environment and those who are subjected to new noise sources also prohibits the use of the NEC method in reverse.

53. In addition, Noise Exposure Category levels should not be used for assessing the impact of industrial or commercial noise upon proposed residential development. This is because this type of noise is generally intermittent or variable in character and will need individual assessment. Insufficient understanding of people's response to industrial noise also inhibits detailed advice to be given. Where a site is subjected to a combination of transport and industrial noise the transport element should, whenever possible, be assessed in terms of the NEC method and the industrial or commercial element in terms of local circumstances (also see paragraphs 35-39).

54. Developments such as offices, hospitals and educational establishments will contain buildings and activities that are noise-sensitive. These developments are likely to occupy sizeable sites and to contain a proportion of buildings and activities that are less noise-sensitive. The NEC principle cannot therefore be sensibly applied to these situations and it will generally be more appropriate to refer to specific guidance on internal noise standards for each activity.

designated areas and the countryside

55. Much of the countryside experiences noise from transport, farming and other rural enterprises. At appropriate levels, these are an accepted part of rural life and may be features of a healthy rural economy. In some lowland rural areas suitable sites may be available for certain activities for which a rural location will be preferred to an urban one because fewer people will be subjected to it. Examples may include boarding kennels, clay pigeon shooting or motor racing facilities.

56. In some cases, noisy development may have a serious effect on the welfare of livestock on nearby farms. Some livestock farms will need to be considered as being noise-sensitive development. The degree to which different species will be affected will vary. Whilst larger animals will generally acclimatise to noise quickly, noise near poultry enterprises, for example, may cause problems. If in doubt, developers should seek veterinary advice.

57. Circular 10/1999 sets out policy for safeguarding designated areas from the adverse effects of noise. Provisions exist for Scottish Natural Heritage (SNH) to be consulted on applications which potentially have an adverse effect on such areas. In circumstances where proposals may raise noise issues and SNH should be consulted for their views on this aspect as well. The effect of noise upon the tranquillity and enjoyment of National Scenic Areas and other areas of landscape and wildlife value should also be taken into account. Further guidance on natural heritage issues is contained within NPPG 14.

58. Particular care will be necessary where noisy development is proposed in or near areas recognised for their environmental value. Proposals likely to affect Sites of Special Scientific Interest (SSSI's) involving wildlife require particular attention. Sites designated as internationally important under the EC Habitats or Birds Directives or the Ramsar Convention also require detailed scrutiny. It should also be remembered that it may be an offence under Part I of the Wildlife and Countryside Act 1981 to disturb protected species.

conditions dealing with noise

59. Where it is proposed to grant permission for noise-sensitive development in areas subjected to high levels of noise, planning conditions should ensure that the effects of noise are mitigated as far as possible (see paragraph 15). For example, intervening buildings or structures may be designed to serve as noise barriers. In some cases, sound insulation measures may be appropriate e.g. of windows although it is reasonable for occupiers of noise sensitive premises to expect satisfactory internal noise levels with their windows sufficiently open for ventilation purposes. Only in exceptional circumstances should satisfactory noise levels be achievable only with windows shut and other means of ventilation provided. Sound levels within a building are not the only consideration; noise can impact negatively upon the environment generally and most residents will also expect a reasonable degree of peaceful enjoyment of their gardens and adjacent amenity areas.

60. In cases where noise sensitive activities are to be permitted near to a noise sensitive development care should be taken to keep the noisiest activities away from the boundary or to provide for measures to reduce the impact of noise. When setting noise levels planning authorities should bear in mind that noise levels in rural and some suburban areas can be low, and that the introduction of noisy activities into these may be especially disruptive.

61. Further advice on the use of planning conditions is given in Annex 3. The addendum to Circular 4/1998 contains some examples of model conditions relating to the control of noise.

62. In exceptional circumstances, planning agreements may be used to limit or mitigate the adverse effects of noise. Advice on the use of planning agreements is given in SODD Circular 12/1996.

enforcement

63. Where planning conditions are imposed to control noise planning authorities should pursue any complaints in the case of alleged non-compliance. Failure to act in respect of planning conditions does not, however, prevent legal action. A key function of the planing system is to protect and enhance amenity. If planning controls have not been imposed to limit noise, then normally the only alternative means of control will be legal action to abate a 'statutory' noise nuisance (see paragraph 67). To be classified as a 'nuisance', noise levels will need to do more than adversely affecting existing levels of amenity. Also, even if a noise is proven to be a nuisance, there may not always be a legal means of successfully abating it. In most circumstances, therefore, it is preferable if development is environmentally acceptable from the outset and planning authorities are encouraged to use planning conditions where they judge there is a need to control noise pollution.

64. Planning authorities may specify in a condition attached to the planning permission that monitoring will be undertaken according to a scheme to be agreed between the planning authority and the developer. Alternatively, a condition might specify a number of noise control points where noise will be measured for monitoring purposes, and the intervals at which the monitoring should be carried out. In the context of large scale developments that pose particularly acute noise issues a number of authorities have found electronic automatic monitoring devices to be accurate and cost effective. Problems may exist, however, in urban locations where extraneous noise makes measurement difficult or where measured levels are only marginally above background noise. Automatically recorded data is also useful in responding to complaints from members of the public about alleged breaches of planning control and in bringing enforcement action against those who breach the limits set out in planning conditions.

environmental assessment

65. European Council Directive 85/337 (as amended by Directive 97/11/EC) requires that an Environmental Impact Assessment be undertaken for certain types of project to be carried out before planning permission is granted. The Environmental Impact Assessment (Scotland) Regulations 1999 will transpose the Directive into Scottish planning law, and supersede the Environmental Impact Assessment (Scotland) Regulations 1988 and all amendments. For projects listed in Schedule 1 of the new Regulations, such as major airports and large mineral extraction sites, EIA is required in every case; for a wider range of projects listed in Schedule 2, including local roads, other aerodrome developments and industrial estates, EIA is required if the proposal is likely to have significant environmental effects. Where EIA is required, the likely effects of noise will be one of the considerations to be dealt with in the environmental statement submitted with the planning application.

other statutory controls

66. It is not the purpose of the planning system to intervene in existing noise problems arising from lawful land use activity. A wide range of statutory powers to control noise exist outside the planning system and the granting of planning permission does not remove the need to comply with these. PAN 51 deals with Planning and Environmental Protection and makes specific reference to noise in Annex 7. Applicants should be advised that the grant of planning permission, and compliance with any conditions attached, will not necessarily protect them from legal action subsequently brought by the local authority or private citizens. Responsibility for this usually falls to the Environmental Health Department of a local authority with whom planning authorities should liase with as emphasised in Circular 10/1999. Further information on these and other noise control regimes is contained in Annex 4.

Conclusions

67. This PAN sets out advice as to how the planning system can implement policy on noise in order to prevent, control and manage possible noise pollution without overlapping with other statutory control measures. It advocates a positive approach towards dealing with noise issues and explains how the planning system can unlock the development potential of sites subjected to noise through the implementation of measures to limit and mitigate the adverse effects of noise. Careful consideration of the impact of noise will do much to maintain and enhance the amenity and quality of life in urban and rural areas alike

notes

68. Enquiries about the content of this PAN should be addressed to David Leven, Planning Services Division, Room 2H, Victoria Quay, Edinburgh, EH6 6QQ, (0131 244 7148) or by e-mail to david.leven@scotland.gov.uk. Further copies of this PAN and other current NPPGs Circulars and PANs may be obtained by telephoning David Love (0131 244 7066). This PAN is also accessible within The Scottish Office web-site at www.scotland.gov.uk/planning/

glossary

-these are explanations of terms used in the PAN and annexes, not definitions

Aerodrome: any area of land, water, or space on the roof of a building, which is commonly used to provide facilities for the landing and departure of aircraft - including types capable of descending or climbing vertically. The term is generic and embraces other terms such as airport, airfield and heliport. For a formal definition see the Civil Aviation Act 1982.

Auxiliary power unit: small engine used to provide power to an aircraft's primary systems (e.g. ventilation and electrical systems) whilst the main engines are shut down.

Hertz (Hz): unit of frequency, equal to one cycle per second. Frequency determines the pitch of a sound

LA10 T: the A weighted level of noise exceeded for 10% of the specified measurement period (T). It gives an indication of the upper limit of fluctuating noise such as that from road traffic. LA10, 18h is the arithmetic average of the 18 hourly LA10, 1h values from 06.00 to 24.00.

LA90 T: the A weighted noise level exceeded for 90% of the specified measurement period (T). In BS 4142 it is used to define background noise level.

LAeqT: the equivalent continuous sound level - the sound level of a notionally steady sound having the same energy as a fluctuating sound over a specified measuring period T.

LAeq T is used to describe many types of noise and can be measured directly with an integrating sound level meter. It is written as Leq in connection with aircraft noise.

LA max: the highest A weighted noise level recorded during a noise event. The time weighting used (Fast or Slow) should be stated.

NNI: Noise and Number Index: A composite measure of exposure to aircraft noise that takes into account the average peak noise level and the number of aircraft in a specific period. Now generally superseded by Leq.

Noise index: a measure of noise over a period of time which correlates well with average subjective response.

Rating level: the noise level of an industrial noise source which includes an adjustment for the character of the noise. Used in BS 4142.

Annex 1: NOISE EXPOSURE CATEGORIES FOR DWELLINGS

1. The purpose of categorisation is to identify the need for development proposals to address noise issues and to put forward recommended standards for noise exposure to which new housing development should comply. Authorities are also reminded that NECs are only to be used when assessing the suitability of new residential development near to an existing transport related noise source.

2. A range of noise levels is given in the table below for each of the NECs. Although the given values are recommended, planning authorities may be able to justify some variation in the range of noise levels they wish to attribute to any or each NEC bearing in mind existing background noise levels. Where there is a clear need for new residential development in, for example, an already noisy area some or all NECs might be increased by up to 3dB(A) above the recommended levels. In other cases, a reduction of up to 3dB(A) may be justified; particularly in tranquil areas.

Noise Exposure Categories

Notes

i) Noise levels (expressed in LAeq) should be representative of typical conditions.
ii) Road traffic noise should be interpreted to mean noise from public highways only.
iii) Railway noise should be interpreted to mean noise from operational railway lines only.
iv) For daytime aircraft, noise values accord with the contour values which relate to levels measured 1.2m above open ground. For the same amount of noise energy (intensity), contour values can be up to 2 dB higher than those of other sources because of ground reflection effects. For small aerodromes planning authorities should not rely solely on Leq where this is based upon less than 30 movements a day. The NEC's should not normally be used to assess helicopter noise; particularly where this is generated by stand alone heliports.
v) 'Mixed sources' refers to any combination of road traffic, railway or air traffic noise. The "mixed source" values are based on the lowest numerical values of the single source limits in the table and should only be used where no individual traffic noise source is dominant. To check if any individual noise source is dominant for the purposes of this assessment, the noise level from the individual sources should be determined and then combined by decibel addition (remembering first to subtract 2dB from any aircraft noise contour values). If the level of any one source then lies within 2dB of the calculated combined value, that source should be taken as the dominant one and the site assessed against the appropriate NEC for that source, rather than using the "mixed source" NEC's. If the contribution of individual sources to overall noise level cannot be determined by measurement or calculation, then the overall measured level should be used and the site assessed against the NEC's for "mixed sources".
vi) Night-time noise levels (23.00 - 07.00): sites where individual noise events regularly exceed 82 dB LAmax (Slow time weighting) more than twice in any hour during this period should be treated as being in NEC C, regardless of the LAeq,8h (except where the LAeq,8h already puts the site in NEC D).

Noise Values and Units of Measurement

3. Noise levels are values recommended by the World Health Organisation1 and based upon research published in 1980. Annex 2 sets out in more detail how these have been derived.

4. In the past, different indices have been used to describe noise from different sources, and limits have been set over different time periods. This has caused confusion, and the approach recommended here follows the move towards consistency advocated in BS7445 Description and measurement of environmental noise by expressing transport noise in terms of LAeq,T (see glossary). The recommended time periods are 07.00-23.00 and 23.00-07.00. During the night period a maximum upper value (82dB(A)) has also been set to protect against infrequent but loud noise events which may not be reflected in the LAeq value.

Categorising Sites

5. There are two conventions in the presentation of environmental data, one which takes account of the effect of the presence of building facades, the other does not (the results being known as free-field). The values in the table are free-field noise levels as would, for example, be measured on a flat open site at the position of the proposed dwellings, well away from any existing buildings. Many sites are neither open nor flat, and site features, which cause noise levels to differ from those on an open site, should be taken into account when categorising sites.

6. Predictions of noise should, wherever possible, take account of the site layout ignoring any features whose presence in the completed development could be ensured only by means of a planning conditions or agreements. Existing land or built forms, which affect the category within which the site will fall can be taken into account but only if their retention can be secured for the duration of the development. This can create practical difficulties. The purpose of the NEC method is to detect the need for planning conditions or agreements and the effect of bunds, barriers or landform should not normally play a part in categorising the site. Noise generated by the development itself, such as traffic, should not affect the categorisation within which the site falls either. But it will need to be taken into account when considering noise mitigation measures.

7. Prediction of road or railway noise should be determined using the calculation procedures, where they are required, of the Noise Insulation (Scotland) Regulations 1975. For noise not addressed by these regulations the Calculation of Road Traffic Noise (CRTN) or Calculation of Railway Noise (CRN) method, as appropriate, may be useful.

8. Where a site falls in one category and part in another, the relevant parts should, wherever possible, be categorised individually. Where this proves impractical the entire site should be placed into the higher, more exacting category. Where a proposed dwelling falls on the boundary between two categories, it should be placed in the more exacting of the two categories.

9. Levels of noise from road and rail traffic are often specified as one metre from a facade, and these facade levels should be assumed to be 3 dB(A) higher than levels measured away from any buildings, unless a more accurate figure is available. For aircraft, the noise levels refer to aircraft noise exposure contour values that are specified at 1.2 m above the ground and published at 3dB intervals. Because most aircraft noise originates from above, contours include the effects of ground reflection. This is why some values for aircraft noise in the table appear higher than for other sources.

10. Measuring points should, be between 1.2 and 1.5 metres above the ground for a single storey development and between 1.2 to 1.5 metres above the proposed internal floor level for each additional storey. For aircraft noise the effect of the height of the proposed development is not normally relevant. The arithmetic average of all recorded readings relating to each individual measuring point should be rounded up to the nearest whole number. Where that average falls on the boundary between NEC's B and C it will be for the local authority to determine which is the more appropriate NEC for the proposal.

Footnote 1 Environmental Health Criterion 12 - Noise (World Health Organisation, 1980)

Annex 2: NOISE EXPOSURE CATEGORIES; EXPLANATION OF NOISE CATEGORIES

1. The following is an explanation of how the boundaries of each of the noise exposure categories (NECs) in the table in Annex 1 have been calculated or derived. Wherever possible figures have been based on research findings or figures contained in statutory regulations. However, the NEC table attempts to give guidance across a broad spectrum of situations and not all of these are covered by existing research work or regulations. In these instances assessments and interpolations have had to be made and these are also explained below.

2. The explanations under each heading make specific reference to each of the transport modes; road, rail, and air. However, separate explanations of "mixed sources" are not given. The "mixed source" values are based on the lowest numerical values of the single source limits in the table.

3. The values given in the NEC table are free-field levels, together with an addition of 2 dB(A) for ground reflection of air traffic noise. Details of correction factors to convert between façade levels and free-field where appropriate are given below. For night-time levels typical insulation values for window installations that are likely to be used in each NEC have been assumed. Because the insulation performance of different window installations is likely to vary, these values are nominal.

Noise levels at the boundary of NEC A and NEC B

Daytime

4. There is no recent, major, UK-based research from which to take figures for road or rail traffic. The level at the boundary of NEC A and NEC B is therefore based on guidance provided by the World Health Organisation1 that "general daytime outdoor noise levels of less than 55 dB(a) Leq are desirable to prevent any significant community annoyance". The figure of 55 dB(a) has been taken to be free-field and therefore no adjustments have been necessary for road and rail traffic noise levels before inserting them in the table. In respect of air traffic noise a considerable amount of research has been carried out.2 57 dB(a) Leq (previously 35 NNI) relates to the onset of annoyance as established by noise measurements and social surveys.

Night-Time

5. As for daytime, there is no recent, major, UK-based research from which to take figures for road or rail traffic. There has been research on the effects of aircraft noise, on sleep disturbance3, which looks at noise levels at which people are awoken from sleep. The night-time noise level at the boundary of NEC A and NEC B is based on the WHO guideline previously referred to1 which states that for night-time: "based on limited data available, a level of less than 35 dB(A) is recommended to preserve the restorative process of sleep" and this is considered more relevant when seeking to achieve the best practicable conditions for rest and sleep.

6. For a site to fall within NEC A noise should not be a determining factor when granting planning permission. It follows that residents may reasonably expect to sleep with their windows open sufficiently to provide adequate ventilation. No guidance is given in the WHO document on the allowance to be made for the sound insulation qualities of a partially open window. This is usually taken to be 10-15 dB(A)4 and for the purposes of the NEC table a reduction of 13 dB(A) from the facade level has been assumed. This would give a recommended maximum figure of 48 dB(A) at the façade. However, as the NEC figures are free-field a correction of -3 dB(A) is necessary giving 45 dB(A) in the table for road and rail noise. For air traffic noise 2 dB(A) has been added to 45 dB(A) to allow for ground reflection, making 47 dB(A). The level in the table of 48 dB(A) is the nearest aircraft dB(A) Leq contour value.

Noise levels at the boundary of NEC B and NEC C

Daytime

7. The daytime noise levels for all three transport modes at the boundary of NEC B and NEC C are based on the levels that trigger official grant schemes. For road traffic noise the trigger level is 68 dB LA10,18h5 at a facade. This has been converted to an LAeq,18h level by subtracting 3 dB, and to an LAeq,16h value by adding 1 dB, giving 66 dB LAeq,16h at a facade. Finally, this figure has been converted to a free-field level by subtracting 3 dB, thus arriving at 63 dB LAeq,16h in the table.

8. For railway noise the trigger level6 is also 68 dB LAeq,18h at a facade. This has been converted to 66 dB LAeq,16h free-field.

9. For air traffic noise, 66 dB(A) Leq,16h5 previously 50 NNI, was the daytime criterion for noise insulation schemes at Heathrow, Gatwick and Stanstead.

Night-time

10. The night-time level at the boundary of NEC B and NEC C for road traffic is, like that at the boundary of NEC A and NEC B, based on the WHO figure of 35 dB(A). Because noise should be taken into account when determining planning applications in NEC B, it has been assumed that the minimum amelioration measure available to an occupant will be to close bedroom windows. Single glazed windows provide insulation of about 25 dB(A).7 Therefore, in order to achieve 35 dB(A) inside a bedroom, the facade level should not exceed 60 dB(A). This facade level requires a further 3 dB(A) adjustment to convert it to the free-field level of 57 dB(A) for road traffic at the boundary of NEC B and NEC C. For rail traffic, the level proposed to trigger the official grant scheme has been adopted. This level is 63 dB LAeq,6h and it has been converted to 59 dB LAeq,8h free-field. For air traffic, the level proposed to trigger the recent grant scheme at Stansted airport8 has been adopted. This level is the 57 dB(A) Leq contour value.

Noise levels at the boundary of NEC C and NEC D

Daytime

11. The noise level at the boundary of NEC C and NEC D for road traffic is based on a Building Research Establishment (BRE) survey9 which has shown that the insulation package supplied under the Noise Insulation Regulations is inadequate for road traffic noise levels of 78 dB LA10,18h and above at a facade. This figure is equivalent to a free-field level of 75 dB LA10,18h; which in turn is equivalent to 73 dB LAeq,16h. The 73 dB LAeq,16h has been reduced by 1 dB to 72 dB LAeq,16h in the table at the boundary of NEC C and NEC D, which is the maximum external level that the standard noise insulation package will reduce to an acceptable internal level.

12. For rail traffic noise no reliable data are available on which to base the level at the boundary of NEC C and NEC D. However, there is some evidence10 that noise from rail traffic causes fewer disturbances than noise from road traffic at the same level. Therefore, the level at the boundary of NEC C and NEC D has been set 2 dB higher than the free-field level for road traffic noise.

13. For air traffic noise the value put forward in Circular 10/73, which is now well established, has been used. This is 60 NNI or 72 dB LAeq,16h5 including a 2 dB allowance for ground reflection.

Night-time

14. The night-time levels at the boundary of NEC C and NEC D are, like those at the boundary of NEC A and NEC B, based on the WHO figure of 35 dB(A). The standard noise insulation package provides insulation of about 35 dB(A)9. Therefore a facade level of 70 dB(A) or above the internal limit for a bedroom of 35 dB(A) may not be achieved. The level of 70 dB(A) has therefore been reduced by 1 dB(A) and a correction factor of 3 dB(A) applied to derive the free-field level of 66 dB(A) in the table at the boundary of NEC C and NEC D for road and rail noise. For air traffic noise the level of 66 dB(A) is the nearest aircraft dB(A) Leq contour value to provide equivalent protection.

Footnotes
1 Environmental Health Criterion 12 - Noise (World Health Organisation, 1980)
2 Directorate of Operational Research and Analysis "The Noise and Number Index" DORA Communication 7907, Second Edition, September 1981.
Brooker, P et al "United Kingdom Aircraft Noise Index Study: Final Report" Civil Aviation Authority DR Report 8402, January 1985.

Critchley, JB and Ollerhead, JB "The Use of Leq as an Aircraft Noise Index" Civil Aviation Authority DORA Report 9023, September 1990.

3 Report of a field study of aircraft noise and sleep disturbance. Department of Transport, 1992.
4 Transportation Noise Reference Book: Edited by Paul Nelson, published by Butterworths, 1987.
5Noise Insulation (Scotland) Regulations, 1975.
6 Noise Insulation (Railways and Other Guided Transport Systems) Regulations 1998 (applicable to England and Wales only).
7 Transportation Noise Reference Book: Edited by Paul Nelson, published by Butterworths, 1987 and Sound Control for Homes, published by the Building Research Establishment and CIRIA, 1993 [BRE report 238, CIRIA report 127].
8 Department of Transport Consultation Paper: Proposed Stanstead Noise Insulation Grants Scheme, September 1990.
9 Utley W et al "The effectiveness and acceptability of measures for insulating dwellings against traffic noise" (Journal of Sound and Vibration (1986) Vol 109(1), pages 1-18).
10 "Railway Noise and the Insulation of Dwelling" Mitchell Committee Report, published February 1991.

Annex 3: CONTROLLING NOISE THROUGH PLANNING CONDITIONS

1. Planning authorities seeking to attach conditions to planning permissions should refer to SODD Circular 4/1998 and its addendum, as well as the advice below. When setting noise conditions that specify noise limits or when monitoring compliance of conditions planning authorities should seek expert advice.

Absolute and relative noise limits

2. With a condition that sets noise limits the developer is able to achieve the required noise level in whatever way is considered most cost-effective - so it may be suitable for speculative developments. A further advantage is that it controls noise in the long term since any future changes within the development must be made in such a way that the limits are not exceeded. However, a disadvantage of this type of condition is that in order to ensure compliance, noise emissions must be monitored either by the developer or by the authority. Whilst monitoring may be costly and time-consuming this should not be regarded as sufficient reason for not using noise conditions.

3. Depending on circumstances, it may be good practice to set either:
an absolute limit based on the level of noise which should not be exceeded in a specified time period;
a relative limit based on the permitted increase in noise level with respect to the background level. This is the approach used in BS 4142.


4. Relative limits are rarely appropriate where the permitted increase in noise over existing noise levels is substantial or where accurate measurement or assessment of background noise levels is not possible. Because background noise varies, the background noise level determined should be representative of a typical quiet time during the period to which the condition relates.

5. Either type of limit may be a single value over the relevant period, or different values for, say, day and night. It may be good practice to set an evening value as well where the noise source lends itself to fine control.

6. A noise limit that is close to the background level will be difficult to monitor. Conditions that seek to safeguard levels of amenity by ensuring that noise resulting from a proposed development is inaudible in adjacent noise sensitive premises may be appropriate in cases where noise lends itself well to fine tuning (e.g. amplified music) although should be used sparingly. In every case conditions should be considered in terms of the six tests set out in Circular 4/1998. Planning authorities should also bear in mind that gaining access to monitoring points contained within adjacent buildings might be problematic. Differentiating between extraneous noise and the noise source under control may also be difficult. Often, noise issues resulting from licensed premises can be effectively controlled by means of a licensing condition. Where planning authorities consider that noise issues are more effectively handled by another means of control then it will be good practice to inform the applicant of the standards that are likely to be applied. This would avoid the situation where construction works are completed but then found to be below the standard required to provide adequate noise protection.

7. The idea of setting an additional overriding maximum level is often attractive, but may be hard to enforce because with unattended monitoring stations it is difficult to exclude extraneous noises which will increase the measured level. There may also be the administrative difficulty of dealing with occasional transient high noise levels from the site. In some circumstances, such as in relation to airport noise, both types of condition may be needed.

Units of measurement

8. Because noises vary over time and have different characteristics many indices have been developed to describe noise levels. The equivalent continuous noise level over a time period T (LAeq,T) has emerged as the best general purpose index for environmental noise. For road traffic noise LA10,18h is still widely used; and to describe background noise LA90,T is appropriate. For noise characterised by definite tonal characteristics the use of Noise Rating (NR) may be applicable. These should not, however, be used to measure noise that is irregular or impulsive in character. To describe the sound insulation of a component of a building envelope (e.g. a window) BS EN ISO 717-1 Rating the sound insulation in buildings and of building elements is appropriate. It is more difficult to specify the insulation of the whole building envelope because the value depends on different insulation values for the various building elements such as windows, walls and roof structure, as well as the type of noise source and its location. These indices are explained in the Glossary. Additional information may be found in BS 7445 Description and measurement of environmental noise.

Monitoring points

9. Normally the noise limit will be chosen to protect the nearest noise sensitive premises and the best position for the monitoring point(s) will be outside the sensitive premises. However, this does not mean that the monitoring point will always be close to the premises. Normally noise limits refer only to noise from the source under consideration and not to the total measured value that may include, for example, transport noise. In situations where extraneous noise makes monitoring difficult, it may be easier to monitor a suitably adjusted level at the boundary of the site instead of outside the premises to be protected with the level set to provide suitable protection at the noise sensitive premises. This approach requires that the monitoring point is a reliable indicator of the level at the noise sensitive premises, which may not be the case if the noise source is mobile. Monitoring points should ideally be accessible to all parties concerned.

Weather effects

10. The noise level measured at a monitoring point will be affected by wind speed and direction, and temperature gradients, particularly when the monitoring point is remote (>30 m) from the source. The size of these effects is hard to predict, and so measurements (or predictions) should be made under reasonably stable conditions. A suitable condition is a light wind with a vector component up to 2 m/s from source to receiver; this will increase the noise level by about 2 dB(A) compared with the no wind case although the existence of vegetation will be likely to influence this.

Limiting activities

11. Planning conditions may specify the type of activity that may take place; any restrictions necessary on the hours of operation; and details of the construction and layout of the development.

12. This type of condition is relatively easy to check for compliance and may prove more effective against certain noise problems. For example, conditions on the location of the access to the development may help to solve the problem of noise in neighbouring residential areas that arises from traffic (particularly heavy vehicles) generated by the development. But control of activity, construction and layout, may prove less effective than noise limits in controlling noise resulting from future changes within the development. In practice, therefore, a combination of both types of condition may prove advantageous. This could entail the developer being given, at an early stage, target noise limits for use in drawing up a scheme of building and operation for the development. If the authority is content that the proposals would satisfy these noise limits the scheme could be incorporated in a planning condition.

Annex 4: INFORMATION ON OTHER NOISE CONTROL REGIMES

1. Some of the most commonly used noise control regimes are briefly discussed below.

The Environmental Protection Act 1990

2. Since April 1st 1996, by virtue of the Environment Act 1995, the Environmental Protection Act 1990 (the 1990 Act) has given Scottish Local Authorities considerable and wide-ranging powers to tackle noise nuisance. S. 79 of the 1990 Act imposes a duty on local authorities to inspect their area from time to time to detect statutory noise nuisances. Where a local authority is satisfied that the noise emitted from any premises is prejudicial to health or constitutes a 'nuisance', it must serve an abatement notice on the person responsible for the noise. This notice may require the abatement of the nuisance or prohibit or restrict its occurrence or recurrence, and may also require the execution of such works and the taking of such steps as are necessary for this purpose. Local Authorities can exercise these controls at any time if satisfied there is a statutory nuisance regardless of the terms of any planning permission.

The Statutory Nuisance (Appeals) Scotland Regulations 1996

3. These Regulations make provisions as regards Scotland with respect to appeals to the sheriff against abatement notices served under section 80 of the Environmental Protection Act 1990. They also amend the Control of Noise (Appeals) (Scotland) Regulations 1983.

The Noise and Statutory Nuisance Act 1993

4. This Act amended Part III of the Environmental Protection Act 1990 by placing additional definitions in the list of statutory nuisances in section 79 of that Act. The definitions related to nuisance caused by vehicles, machinery and equipment in the road.

The Control of Pollution Act 1974

5. The Control of Pollution Act 1974 (the 1974 Act) was largely repealed by the Environmental Protection Act 1990. However, those sections that are extant give local authorities powers to control noise from construction sites, and noise from loudspeakers in streets. The Act also introduced the concept of the Noise Abatement Zone (NAZ) which provides a more sophisticated means of controlling, and, where justified, reducing noise from commercial and industrial premises, particularly in areas of mixed development. Although NAZs have been criticised for their complexity, and although few have been designated in recent years, the powers available in such zones, for example, the serving of a nuisance abatement notice remains useful in tackling some types of urban noise problem.

Temporary use of land

6. Under Part 4 of Schedule 1 to the Town and Country Planning (General Permitted Development) (Scotland) Order 1992, certain temporary activities enjoy permitted development rights. These allow the land (not buildings) to be used for not more than 28 days (14 days in the case of caravan sites or open-air markets) in any one calendar year without the need to apply for planning permission. Where they judge circumstances warrant it a local authority may make a direction under article 4 of this Order which withdraws the general permission and so requires anyone wishing to institute the particular use to make a specific planning application. If an article 4 direction is to remain in force for more than six months, then the approval of the Secretary of State for Scotland is necessary. Compensation may be payable if permission on a subsequent planning application is refused, or is granted subject to conditions.

The Building Regulations

7. The Building Standards (Scotland) Regulations 1990 (as amended) impose requirements for sound insulation of separating walls and floors between dwellings. These are set out in Part H of the Technical Standards for compliance with the Building Standards Regulations (Resistance to transmission of sound). Although the Building Regulations are not directly concerned with control of external noise they do cover thermal insulation of windows and provision of adequate ventilation.

8. The Building Standards (Scotland) Regulations 1990 came into force on 1 April 1991. The requirements apply equally to new-build dwellings and those created by conversions, although local authorities have the power to grant a relaxation and are likely to do so in the case of conversions if the full application of the requirements is deemed to be unreasonable. The Government considers that the Building Regulations are the most appropriate means of control for sound insulation in such conversions, and planning authorities should not therefore use planning conditions to control sound insulation in such cases. However, this does not preclude the use of conditions designed to protect amenity where planning approval is required for change of use to a noisy activity of premises adjacent to dwellings (e.g. a conversion to a cafe, discotheque or other noisy undertaking) where dividing walls or a floor separate a dwelling from such a use.

Codes of Practice

9. Under the 1974 Act the Secretary of State also has the power to prepare and approve Codes of Practice for the purpose of giving guidance on how best to minimise or reduce noise. To date four Codes of Practice have been introduced (Noise from Audible Intruder Alarms HMSO 1982, Noise from Ice Cream Van Chimes Etc. HMSO 1982, Noise from Model Aircraft HMSO 1982, and Noise Control on Construction and Open Sites (BS 5228, Parts 1 and 3 HMSO 1984 ; Part 4 HMSO 1986). In addition, many of the governing bodies of sport have produced codes of conduct which are used when organising events, and these should be consulted when new sites are being selected. The Sports Council, for example, has published reports on Providing for Motor-sports (1986) and Providing for Motorised Water Sport (1990). The Noise Council has also produced a Code of Practice on Environmental Noise at Concerts (The Noise Council 1995). The Codes approved by the Secretary of State do not have the force of law, but may be helpful to local authorities and Sheriff courts as examples of best practice.
By-laws

10. Some noise sources may be controlled by by-laws made by local authorities, particularly certain kinds of noise taking place in streets or in parks and recreation grounds. There are also certain old by-laws in some areas which cover other types of noise nuisance now subject to control under the 1974 or the 1990 Act: such by-laws may still be valid, but no new by-laws of this kind are likely to be confirmed unless they can be shown not to duplicate existing legislation.

European Community Directives

11. The European Community has issued directives focused on limiting noise from products, particularly modes of transport, construction equipment and other specific products such as lawnmowers and household appliances. The major existing directives are as follows:

70/157 (as amended) Council Directive relating to the permissible sound level and the exhaust systems of motor vehicles.
78/1015 (as amended) Directive on the permissible sound level and exhaust system of motorcycles.
74/151 (as amended) Directive relating to certain parts and characteristics of wheeled agricultural or forestry tractors.
79/113 (as amended) Directive relating to the determination of the noise emission of construction plant and equipment.
84/532 Directive on the approximation of the laws of the Member States relating to common provisions for construction plant and equipment.
86/662 Directive on limitation of noise from hydraulic excavators, rope-operated excavators, dozers, loaders and excavator loaders.
80/51 (as amended) Directive on the limitation of noise from subsonic aircraft.
84/538 (as amended) Directive on the approximation of the laws of the Member States relating to the permissible sound power level of lawnmowers.
86/188 Directive on the protection of workers from the risks related to exposure to noise at work.
86/594 Directive on airborne noise emitted by household appliances.

Currently, the European Union (EU) is proposing a new Directive on noise from outdoor equipment, which will supersede some of the Directives listed above. Separately, a Green Paper on Future EU Noise Policy has led to proposals for a framework noise Directive. It is expected that this will be produced some time in the year 2000.

Noise at work

12. The Noise at Work Regulations 1989, which are enforced by inspectors of the Health and Safety Executive (HSE), require employers to take a number of steps to protect employees from exposure to excessive noise.
Civic Government Scotland Act 1982

13. Section 54 of the Civic Government (Scotland) Act 1982 allows the police to take action against the 'playing of sound devices'. This includes powers to confiscate such equipment as evidence in court. The police also have wide-ranging powers that can be used to deal with noise under the common law offence of a breach of the peace.

The Criminal Justice and Public Order Act 1994

14. This Act gave police supplementary powers of entry and seizure of vehicles and sound equipment. It provides a definition of 'sound equipment'.

The Crime and Disorder Act 1998

15. In addition to giving local authorities further powers to deal with nuisance and anti-social behaviour, this Act also amended the Civic Government (Scotland) Act 1982, by giving police a specific power of seizure in relation to sound proofing devices causing annoyance.