“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”

-

JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”

-

LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”

-

DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”

-

MT, Lark Energy

Big Changes to BS4142

BS4142:2014 provides a method that can be used to assess the potential impact of noise from commercial or industrial noise sources affecting residential properties. BS4142 assessments are commonly requested by Local Planning Authorities and used to determine the acceptability of proposed developments and to assess the need for additional noise mitigation in the design of the developments.

To carry out a BS4142 assessment, you first measure the background noise level (LA90) at the position of the affected residential properties in the absence of the industrial or commercial noise. The background noise level is defined as the noise level exceeded for 90% of a given time period.

For example, below is a graph of noise levels measured in a garden over a short period. The orange line represents the change in noise level during the measurement. The grey line shows the calculated background noise level for measurement, which was 53.6 dB LA90.

background-noise1

The background noise level represents the underlying noise environment at the site in the absence of short-term and atypical noise events. In this measurement, the background noise level was dictated by distant traffic – this is common for many sites in England.

Once you have established the background noise level at the position of the residential properties, you then measure or predict the average noise level (LAeq) from the new commercial or industrial noise source under investigation at the same positions.

The likely impact of the commercial or industrial noise on the residential properties can then be assessed by comparing the predicted or measured commercial or industrial noise level with the background noise level at each residential position. BS4142 states that, for commercial or industrial noise with no distinguishable features:

  • The louder the commercial/industrial noise is compared to the background noise level, the greater the magnitude of the impact;
  • If the commercial/industrial noise is 10 dB or more higher than the background noise level then this is an indication of a significant adverse impact (i.e. this is not normally acceptable);
  • If the commercial/industrial noise is around 5 dB higher than the background noise level then this is an indication of an adverse impact (i.e. this should be avoided if possible);
  • If the commercial/industrial noise is lower than the background noise level, this is an indication of a low impact (i.e. this is normally acceptable). The lower the commercial noise level is, the lower the likely impact.

BS4142 also provides corrections that should be applied to the predicted or measured commercial/industrial noise levels where the commercial/industrial noise contains characteristics that make the noise more intrusive. These characteristics include tonality, impulsivity, and intermittency. The corrections can be significant, meaning that noise containing these characteristics may be severely penalised. The corrections are summarised below.

BS4142:2014 Corrections for tonality etc

Commercial/industrial Perceptibility
noise characteristic Just perceptible Clearly perceptible Highly perceptible
Tonality +2 +4 +6
Impulsivity +3 +6 +9
Intermittency 0 +3 +3
Other sound characteristics 0 +3 +3

Importantly, more than one correction may apply. For example, if a noise is both highly tonal and impulsive then a correction of +15 dB may be applicable. In this case, even if the commercial/industrial noise level was equal to the background noise level, the BS4142 rating would be +15 dB above background, and therefore deemed to result in a “significant adverse impact”.

Whilst the assessment criteria outlined in BS4142:2014 are relatively prescriptive, it is important to note that people’s response to sound is subjective and therefore factors such as the character of a neighbourhood and/or local attitudes to the source of the sound can also significantly affect the impact and therefore should be considered. For example, it may be appropriate to adopt lower plant noise limits in areas prized for their tranquillity where no industrial or commercial noise currently exists.

Ultimately everyone may have different view on what level of noise is acceptable or not. However, BS4142 provides us with a useful tool to help ensure that a reasonable balance is achieved between residential amenity and the need for businesses to generate some noise.

It should also be noted that BS4142 is not the only tool for the design and planning of new developments and may not be appropriate in all cases. For example, BS8233:2014 – Guidance on sound insulation and noise reduction for buildings provides specific advice on the design of external facades of residential buildings to achieve acceptable noise levels in internal rooms such as bedrooms and living rooms.

If you would like more information on BS4142 or would like to discuss a project in confidence, please call Chris McNeillie or Patrick Allen on 01234 834 862.

BS4142:2014 – Method for rating and assessing industrial and commercial sound has recently been updated including a number of important changes. These changes may have significant ramifications for developers building new commercial or industrial uses (including items such as fixed external mechanical plant) near to existing residential properties, or for developers of new residential properties near to existing commercial or industrial uses.

The first main change is the scope of the standard. The previous version, BS4142:1997, provided an assessment methodology that could be used to assess the “likelihood of complaints” due to commercial or industrial noise. The scope of the methodology in BS4142:2014 is to assess the “likely impact”. This is a subtle but important change that brings BS4142:2014 in line with other guidance including the Noise Policy Statement for England and the National Planning Policy Framework.

The standard now also specifically states that it can be used to assess the impact of existing industrial or commercial uses on proposed new residential developments. This wasn’t clear in the previous version.

The assessment method is fairly similar to the previous version in that the likely impact of commercial or industrial noise is still assessed by comparing the predicted or measured commercial/industrial noise level with the background noise level at residential positions.

BS4142:2014 states that, for commercial or industrial noise with no distinguishable features:

  • The louder the commercial/industrial noise is compared to the background noise level, the greater the magnitude of the impact;
  • If the commercial/industrial noise is 10 dB or more higher than the background noise level then this is an indication of a significant adverse impact (i.e. this is not normally acceptable);
  • If the commercial/industrial noise is 5 dB or more higher than the background noise level then this is an indication of an adverse impact (i.e. this should be avoided if possible);
  • If the commercial/industrial noise is lower than the background noise level, this is an indication of a low impact (i.e. this is normally acceptable). The lower the commercial noise level is, the lower the likely impact.

The criteria above is similar to the previous standard, other than the removal of the “background minus 10 dB” criterion (BS4142:1997 used to state that if the commercial/industrial noise was 10 dB below the background level then this would indicate a “low likelihood of complaints”).

However, the removal of the “background minus 10 dB” criterion is offset by significant changes to the corrections that should be applied to predicted or measured commercial/industrial noise containing intrusive characteristics. These characteristics include tonality, impulsivity, and intermittency. The corrections in BS4142:2014 are now potentially much higher, meaning that noise containing these characteristics will be severely penalised. The corrections are summarised below.

BS4142:2014 Corrections for tonality etc

Commercial/industrial Perceptibility    
noise characteristic Just perceptible Clearly perceptible Highly perceptible
Tonality +2 +4 +6
Impulsivity +3 +6 +9
Intermittency 0 +3 +3
Other sound characteristics 0 +3 +3

Importantly, more than one correction can apply. For example, if a commercial/industrial noise is both highly tonal and impulsive then a correction of +15 dB may be applicable. This is a significant correction and could determine the predicted acceptability of the noise source.

Whilst the assessment criteria outlined above appear relatively prescriptive, the new version of BS4142 stresses that the response to sound is subjective and therefore other less tangible factors such as the character of a neighbourhood and/or local attitudes to the source of the sound should also be considered as part of an assessment. The new standard also introduces a requirement to consider uncertainty, i.e. the risk of tolerances in predictions, measurements and other variables resulting in inaccuracies in the conclusions of the assessment.

Given the requirement to consider the additional qualitative factors above, it is unsurprising that the new standard specifies that assessments should only be undertaken by “appropriately qualified and experienced people”. The Association of Noise Consultants are considering starting an accreditation scheme in this regard.

The requirement for more consideration of these less tangible factors may be appropriate however in the absence of set guidance within the standard there is likely to be more disagreement on the appropriate BS4142 assessment methodology and criteria for any given development, as well as more variation in local authority requirements. This has the potential to lead to significant problems for developers.

It will therefore be more important going forward that developers ensure they liaise with local authorities early in the design process to agree the BS4142 criteria and assessment methodology in order to minimise the risk of disagreements resulting in expensive redesigns and rejected planning applications.

If you would like more information on BS4142:2014 or would like to discuss a project in confidence, please call Chris McNeillie or Patrick Allen on 01234 834 862.

In October 2014, a revision of BS4142 – methods for assessing and rating industrial and commercial sound for residential developments, was published.

BS4142 assessments are commonly requested by Local Planning Authorities and used to determine the acceptability and design of proposed developments with regards to noise.

1. What Has Changed?

  • The scope has changed from assessing the “likelihood of complaints” to the “likely impact” of commercial or industrial noise. This brings the standard in line with other guidance including the Noise Policy Statement for England and the National Planning Policy Framework.
  • It now specifically states that it is applicable to situations where new residential developments are proposed next to existing industrial or commercial uses.
  • It now stresses that the response to sound is subjective and therefore factors such as the character of a neighbourhood and/or local attitudes to the source of the sound can also significantly affect the impact and therefore should be considered as part of the assessment.
  • It also introduces a requirement to consider uncertainty, i.e. the risk of tolerances in predictions, measurements and other variables resulting in inaccuracies in the conclusions of the assessment.
  • The corrections for tonality, impulsivity and other noise characteristics are now potentially much higher, meaning that some types of noise can be severely penalised.
  • It specifies that assessments should only be undertaken by “appropriately qualified and experienced people”. The Association of Noise Consultants are considering starting an accreditation scheme in this regard.

2. What Do The Changes Mean For You?

  • These changes may have implications for new commercial or industrial developments near to existing residential properties, or for new residential developments near to existing commercial or industrial uses.
  • There is likely to be more disagreement on the appropriate BS4142 assessment methodology and criteria for any given development, as well as more variation in local authority requirements. This has the potential to lead to significant problems for developers.

3. What You Need To Do About It

  • Liaise with local authorities early in the design and planning process to agree the BS4142 criteria and assessment methodology. This will minimise the risk of disagreements resulting in expensive redesigns and rejected planning applications.
  • Ensure assessments are only undertaken by “appropriately qualified and experienced people”.

4. We Are Here to Help

  • Please call 01234 834862 and ask for either Chris McNeillie or Patrick Allen.

5. Further Information on BS4142:2014

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