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08450 666966
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4477
Airtight & Noisecheck Ltd
236c Havant Road, Drayton
Hampshire PO6 1PA
Acoustic Design Advice
We offer a consultancy service whereby we can be involved from the conception of the development, available to advise on suitable construction methods and separating elements to be used. Our expert knowledge of the construction industry, the knowledge of advantages and disadvantages of different systems and our computer based software prediction program ensure that we will have all of the aspects covered. We can arrange a specific consultancy program to suit your individual requirements, this could include:
- Site meetings
- Design meetings - remote location working from drawings
- Observation and comments of specifications
We have in depth knowledge of testing to 'code for sustainability' and we can advise on improvements to methods to ensure that the minimum standards are exceeded by the necessary amounts to achieve the necessary credits.
Noise Impact Assessments
At the beginning of any development/project (residential, commercial, industrial) a noise impact assessment/ noise survey will be required to ensure the suitability of the proposal in relation to the site location, existing residential dwellings etc. We offer a wide range of noise surveys that can be tailored to your specific needs, we will speak with the local authority to ensure that we carry out all of their requirements.
New residential developments
If a planning application has been made to implement a residential scheme, the local authority can insist on noise conditions being imposed. Therefore a noise survey will be required, to ensure that the ambient noise levels will not adversely affect the reasonable standard of living for the future residents of the proposed scheme. The propose site may be near to a busy road, railway line, airport or all of the above, the noise survey will determine the exact noise emissions produced at the site and therefore what measures should be implemented to ensure future protection against noise.
The noise levels are generally monitored at the nearest noise sensitive façade in relation to the noise source, more than one location can be measured simultaneously if there are more than one noise source evident. From the findings a detailed report will be issued explained what measures are required to each aspect of the site.
'Planning Policy Guidance 24: Planning and Noise' (PPG24) is generally the standard adhered to when performing such noise surveys, this document states 'when assessing a proposal for residential development near a source of noise, local planning authorities should determine into which of the four noise exposure categories (NECs) the proposed site falls, taking account of both day and night-time noise levels'. The four NEC's are then used to determine the planning conditions that are granted for the development. The associated noise levels apparent for each (NEC), and a description of each (NEC) is listed below.
Noise Levels Corresponding To The Noise Exposure Categories
For New Dwellings LAeq,T dB
NOISE EXPOSURE CATEGORY
NOISE SOURCE
A
B
C
D
Road Traffic
0700 - 2300
<55
55-63
63-72
>72
2300 - 0700
<45
45-57
57-66
>66
Rail Traffic
0700 - 2300
<55
55-66
66-74
>74
2300 - 0700
<45
45-59
59-66
>66
Air Traffic
0700 - 2300
<57
57-66
66-72
>72
2300 - 0700
<48
48-57
57-66
>66
Mixed Sources
0700 - 2300
<55
55-63
63-72
>72
2300 - 0700
<45
45-57
57-66
>66
- NEC A - Noise need not be considered as a determining factor in granting planning permission, although the noise level at the night end of the category should not be regarded as a desirable level.
- NEC 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.
- NEC C - Planning permission should not normally be granted. Where it is considered that permission should be given, for example because there are no alternative quieter sites available, conditions should be imposed to ensure a commensurate level of protection against noise.
- NEC D - Planning permission should normally be refused.
We can list the specification needed from the building elements such as, the façade, roof and windows. In many cases it is necessary to upgrade the windows or install mechanical ventilation to ensure the necessary reductions have been achieved.
Mixed residential & industrial areas:
The most relevant criteria to assess the impact of a new noise source located, or proposed to be located, close to residential developments is contained within BS4142:1997 - Rating industrial noise affecting mixed residential and industrial areas. This British Standard describes a method assessing whether the installation of or the existing industrial plant will increase the likelihood of complaints for the nearby residential dwellings. The level of expected complaints depends on not only the level of noise emissions but also on the tone, intermittence and duration of the noise source.
If the proposed plant will run through the night then readings have to be taken during this time along with the daytime measurements, LA90 measurements should be taken for an hour during the day (0700 - 2300) and 5minutes during the night (2300 - 0700) and these readings are compared to the specific noise level (or data) of the proposed plant. The level of complaints will vary depending on the difference between the rating level and the LA90, the bigger the difference the higher the likelihood of complaints. There are certain acoustic features that will increase the noise levels produced, these include:
- The noise contains a distinguishable, discrete, continuous note (whine, hiss, screech, hum, etc.)
- The noise contains distinct impulses (bangs, clicks, clatters, or thumps)
- The noise is irregular enough to attract attention.
If the noise does contain of the above then a +5dB correction will be added to the specific noise level. The likelihood of complaints in correlation to the difference between the two levels is listed below:
- A difference of around +10 dB or more indicates that complaints are likely.
- A difference of around + 5 dB is of marginal significance
- If the rating level is more than 10 dB below the measured background noise level then this is a positive indication that complaints are unlikely
Each site is very different and will undoubtedly require a site specific noise survey, do not hesitate to contact us to discuss your particular requirements and we will tailor the noise assessment to suit you. We will then use the relevant British Standard and associated documents to ensure that the necessary information is included and all aspects have been covered.
We have extensive knowledge is carrying out noise surveys and have produced reports for:
- Nightclubs
- Public Houses
- Residential Developments
- Industrial Plant Noise
- Commercial Projects
For more information please telephone 08450 666966 or email us >