PROPOSED SKATEPARK: MEMORIAL PLAYING FIELD:...

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PROPOSED SKATEPARK:

MEMORIAL PLAYING

FIELD: STEYNING

AS7313.130218.NIA

An Assessment of the Impact of a Proposed

New Skatepark on nearby Residential

Premises

Prepared: 18th

February 2013

Friends of Memorial Playing Field

c/o 5 Charlton Street

Steyning

West Sussex

BN44 3LE

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List of Attachments

AS7313/SP1 Site Plan showing noise survey location and the proposed skatepark location

AS7313/TH1 – 4 Time Histories showing the current typical noise levels at nearby residential properties

Appendix A Acoustical parameters

Appendix B Calculations AS7313/C1&C2 Base design

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AS7313 PROPOSED SKATEPARK, MEMORIAL PLAYING FIELD, STEYNING Page 1 of 19

Noise Impact Assessment

Y:\JOB FILES\7000-7999\7300s\7313 Steyning Skatepark, BN44 3LE\7313 Reports\7313.130218.NIA.docx

1. INTRODUCTION

It is proposed to construct a new skatepark in the Memorial Playing Field, Steyning, West

Sussex. The proposed location is on the site of the current basketball court on the

western boundary of the playing field.

The closest affected residential property is ‘Byways’ in Mill Road to the north of the

playing field. It is approximately 90 metres from the centre of the proposed skatepark

location to the dwelling. The property ‘Toad Lodge’ and others on Newham Lane to the

south of the playing field are also some 110 metres from the centre of the proposed

skatepark. Because of the landform of the playing field, these are also noise sensitive

properties. The noise climate in the area has some road traffic noise from Charlton Street,

Mill Road and Newham Lane, but is generally a quiet area.

Alan Saunders Associates (ASA) have been commissioned by the Friends of the Memorial

Playing Field to undertake a noise survey of the prevailing background noise climate and

subsequently assess the suitability of the site for the skateboard park facility in relation to

current standards and guidance documents and other appropriate assessment

procedures. ASA have also been asked to review noise impact reports produced for

Steyning Parish Council, originally by Atkins (September 2012) and subsequently by

Acoustic Dimensions (November 2012). Both of these reports have been submitted to

Horsham District Council (HDC) in support of a planning application for the skatepark.

2. SURVEY PROCEDURE

An environmental noise survey was carried out over the extended weekend period from

14:30 hours on Thursday 31st

to 12:00 hours on Monday 4th

February 2013.

Measurements of the LAmax,fast, LA10, LAeq, and LA90 noise levels were made over consecutive

10 minute periods. The following equipment was used for the survey.

• Norsonic Data Logging Sound Level Meter Type 116

• Gras Environmental Microphone Type 41AL

• Norsonic Sound Level Calibrator Type 1251

The measurement location in the garden of Toad Lodge in Newham Lane was considered

to be representative of the typical noise levels existing at the closest residential

ALAN SAUNDERS ASSOCIATES AS7313.130211.NIA 18th

February 2013




properties to the proposed skatepark site. The microphone was set up in the rear garden

at approximately 1.8 metres above ground level. This measurement location is shown in

the site plan AS7313/SP1, where the location of the proposed skatepark is also indicated.

The calibration of the equipment was verified before and after use. No calibration drift

was observed. Measurements were made generally in accordance with ISO 1996-2:2007

Acoustics - Description, measurement and assessment of environmental noise –

Part 2: Determination of environmental noise levels.

Because of the time permitted by HDC the weather conditions were not ideal during the

survey period with gusty winds. Since the survey was carried out, however, to determine

predominantly the background LA90 noise levels, these levels would be less affected by the

wind gusts. During the less windy periods of the day, the typical LAeq,10m and LAmax values

are representative of typical values. The validity of the ASA measurements is confirmed

by the measured LA90 levels during the survey being about the same or lower than those

levels measured by both Atkins and Acoustic Dimensions during their very short term

surveys.

An explanation of the acoustic terminology used in this report is in given in Appendix A.

3. RESULTS

Figures AS7313/TH1-TH4 show the LAeq, LAmax,fast, LA10 and LA90 as 10 minute environmental

noise levels. The Steyning Parish Council (SPC) ‘Operational Management Plan’, published

as part of the planning process indicates an operational period for the skatepark from

08:30 until dusk. The term ‘dusk’ is non-specific but is qualified in the proposed notice at

the rear of the Management Plan as ‘not to be used when it is dark’. During the summer

evenings this could be as late as 22:30 hours but a closing time of 21:00 hours has been

assumed as a reasonable end to the day based on previous experience of use at many

other skateparks. Since there is no security fencing proposed, however, there is nothing

to prevent use outside this period when any impact would be significantly greater than

predicted in this assessment as the background noise level reduces.

Typical noise levels measured on site are shown in Table 3.1.


February 2013




Assessment period

08:30 – 21:00 hrs Typical LAeq,10m (dB) Typical LA90,10m (dB) Typical LAmax,fast (dB)

Byways & Toad Lodge 43 30 – 38 60

Table 3.1 – Current measured noise levels [dB ref 20µPa]

Reviewing historical hourly weather data for Steyning and the Time History plots, the

afternoons of Thursday 31st

January; Saturday 2nd

February; and Sunday 3rd

February gave

acceptable wind speeds, for which the above measured LA90 levels of 30-38dB are

representative of levels over the proposed operational periods. A typical level of 35dB: LA90

has, therefore, been used in the subsequent noise impact assessment for the proposed

skatepark.

It should be noted that, whilst Atkins undertook manual background measurements until

19:3 0 hours and show similar levels to those measured by ASA, the Acoustic Dimensions

report contains no measurements beyond 15:00 hours and does not, therefore, represent

the actual ambient (LAeq) and background (LA90) noise levels during the late afternoon and

early evening when the impact of the skatepark is likely to be at its maximum.

4. METHODS OF ASSESSMENT

In relation to the noise produced by leisure activities, such as skateboarding, there are no

specific assessment methods or criteria in relation to noise impact. There are, however, a

number of assessment methods which are related to activities where sudden loud noises

occur during skateboarding (Lmax) heard against a generally quiet underlying background

(L90). A comparison of the LAeq,T (the average energy during the time T) with the

underlying background L90 is also relevant to the impact on nearby residential properties

and other tranquil uses. These methods have been used extensively by Alan Saunders

Associates in relation to skateboard noise for both assessment and the design of actual

skateparks. These methods were accepted by the court in the landmark case in relation

to skateboard noise, Richardson v Devizes Town Council, where the judgement forced the

Local Authority to remove the skatepark equipment and awarded substantial damages

and costs to Mr Richardson. These assessment methods have been adopted by a number

of local authorities and other acoustic consultants.

In order to assess the impact of noise from the skatepark, reference should be made to

published guidelines which reflect current scientific thinking and Government advice. This


February 2013




‘good practice’ of using assessment methods which are relevant and helpful, is endorsed

by the procedures set out in the draft document BS9142: Guidelines for Environmental

Noise Management.

Measurements of skateboard/skatepark use noise have previously been undertaken at

numerous other sites by Alan Saunders Associates as part of design and research projects

for bowl and ‘street scene’ skateparks. The data that will be used for this assessment

were measured at a concrete skatepark, which is the same as the likely proposed

construction material and semi bowl type for this site. The data for this assessment uses

the average noise level (LAeq,1h: 54.5dB) generated by approximately 20 skaters with

typically 5 using the skatepark bowls and ramps measured at a distance of 40m from the

centre of the skatepark. To ensure a robust assessment, this level has been used

throughout. Even with fewer overall numbers of skaters, its use by 5 skaters during much

of the opening hours is probable during the school holidays and at weekends. Maximum

noise levels of skateboarding events (LAmax:71.0dB) have also been measured at a distance

of 45m which relate to use of the ‘street scene’ parts of the skatepark, which will be used

to assess event noise. The noise levels will be calculated to approximately 3.5m outside

the rear facades of the nearest residential receivers in Mill Road and Newham Lane, using

standard sound propagation theory.

From experience, all of the following three methods of assessment need to show

acceptable noise levels for a new skatepark to ensure that complaints in relation to

activity noise are unlikely to occur. In practice, the third method of assessment based on

the CIEH document ‘Clay Target Shooting, Guidance on the Control of Noise’ is the most

sensitive as it relates specifically to the maximum noise levels, which are the most

common cause of complaints in relation to skateboard noise.

4.1 British Standard BS4142: 1997

British Standard BS4142:1997 Method for rating industrial noise affecting mixed

residential and industrial areas is designed explicitly to assess the noise impact from

industrial noise on residential properties, and does not refer to any recreational areas.

However, due to the lack of guidance when assessing skatepark noise and the

quantification of tonal, impulsive or intermittent noise upon residential receivers, BS4142

can at least provide some guidance as to the likelihood of complaints, even though it may

not be specifically designed for this purpose. As stated earlier, this assessment


February 2013




methodology has been accepted by the court in the case of Richardson v. Devizes Town

Council with regard to skatepark noise impact.

In order to quantify the impact of the skateboard activities, the British Standard BS 4142

is useful since it considers the character of the noise. This standard compares the noise

levels in terms of an LAeq for a one hour period during the daytime (07:00 – 23:00 hours)

and a five minute period during the night-time (23:00 – 07:00 hours) for the noise source

in operation, the ‘Specific Noise Level’, with the existing background noise level in terms

of an LA90 when the noise source is not operating.

As part of the assessment, consideration is given to the character of the noise.

The standard states:

‘If the noise contains a distinguishable, discrete, continuous note (whine, hiss,

screech, hum, etc.), or if there are distinct impulses in the noise (bangs, clicks,

clatters, or thumps), or if the noise is irregular enough to attract attention,

add 5dB to the Specific Noise Level to obtain the Rating Level’.

From observations, skateboarding noise is transient with many bangs as the skaters hit

the top of the ramps or jump on and off the equipment. This + 5dB ‘character correction’

has, therefore, been applied in subsequent calculations.

This standard then compares the noise level corrected for any ‘character correction’ as

an LAeq 1 hour (for daytime) for the noise source in operation, called the ‘rating level’ with

the existing underlying ‘background noise level’ in terms of an LA90 when the noise source

is not operating. The arithmetical difference between the ‘rating level’ and the

background is called the ‘assessment level’.

BS4142 indicates for the ‘assessment level’, in relation to noise sources of an industrial

nature:

• ‘A difference of around +10 dB or higher indicates that complaints are likely.’

• ‘A difference of around +5 dB is of marginal significance.’


February 2013




• ‘If the rating level is more than 10 dB below [i.e. -10dB(A)] the measured

background noise level then this is a positive indication that complaints are

unlikely.’

For new skateparks, however, an assessment level of 0dB has been used as a criterion of

acceptability to ensure a robust assessment of the noise impact of skateboarding noise.

The measured noise levels for skateboarding activities at another concrete bowl

skatepark being used simultaneously by about 5 skaters have been used historically as the

basis for this assessment. These measured levels have been corrected for distance so as

to give the levels outside the closest properties. The closest residences, which would be

most affected by noise from the skate park, would be the rear elevations of ‘Byways’ in

Mill Road and ‘Toad Lodge’ in Newham Lane.

These predicted noise levels are shown in Table 4.1 based on the calculations

AS7313/C1&C2 shown in Appendix B to this report for the base design. These indicate

the Specific Noise Level: LAeq,1hr values for skateboarding which have been used for the

BS4142 assessments.

Condition Location ‘Specific Noise Level’

LAeq,1h (dB)

‘Rating Level’

LAeq,1h (dB)

Typical Background

LA90,10 m (dB)

Skateboarding noise to

Byways, Mill Road Position 1 47 52 35


Toad Lodge, Newham

Lane

Position 2 46 51 35

Table 4.1 – Measured skateboarding noise levels dB ref 20µPa

Summarising the differences between the ‘rating level’, and the current ‘background’ LA90

level over the proposed opening hours of 08:30 – 21:00 hours, the following ‘assessment

level’ has been predicted.

Location ‘Assessment Level’ (dB) BS4142:1997 Assessment


Byways, Mill Road +17dB

Complaints are very likely for

skateboarding noise


Toad Lodge, Newham Lane +16dB

Complaints are very likely for

skateboarding noise

Table 4.2 – Predicted ‘assessment level’ dB ref 20µPa


February 2013




The above indicates that the predicted rating noise level at both receptors from the new

skatepark would be significantly above the current typical background noise level and

would not achieve the rating level criterion for skateboard noise of 0dB. The indicated

levels would certainly result in complaints from residents.

4.2 World Health Organisation: Guidelines on Community Noise: 1999

The WHO document Guidelines for Community Noise sets out guidance on external noise

levels at which there will be an unacceptable impact on communities. This guidance

considers many different types of noise sources. In paragraph 4.1.7 the impact of noise

on dwellings is considered. The document states:

‘During the daytime, few people are seriously annoyed by activities with

[steady] LAeq levels below 55dB; or moderately annoyed with LAeq levels below

50dB. Sound pressure levels during the evening and night should be 5 -10dB

lower than during the day [i.e. 45 – 50dB serious annoyance; 40 – 45dB

moderate annoyance]. It is emphasised that for intermittent noise [such as the

skateboarding activities] it is necessary to take into account the maximum [i.e.

the LAmax] sound pressure level as well as the number of events.’

The levels referred to above are LAeq,16h values. As a worst case, assuming pessimistically

that skateboarding on the new park is continuous for 9 of the 16 daytime hours, the

LAeq,16h close to the rear facades of the two receptor properties would be approximately

42-43dB(A). These values are within the limits indicated above for day or evening and

indicate that the WHO Guidelines would consider these levels to be within acceptable

levels in the nearby gardens. This level is about the same as the current evening LAeq

noise levels at the receptors measured during the Atkins survey.

4.3 Comparison of Skateboard Noise to Gunshot Noise

The sudden nature, duration and the character of the skateboard impact noise during

jumps and turns, etc., by skateboarders bears a close aural similarity with the noise from

gunshots at a distance.

There have been a number of research investigations into what levels of gunshot noise

cause annoyance to residential occupants, notably by Sörensen S & Magnusson J, G F

Smoorenburg and Hoffman. The current thinking on their impact which generally agrees

with the previous research, has been published as ‘Clay Target Shooting, Guidance on the


February 2013




Control of Noise’ published by the Chartered Institute of Environmental Health Engineers

in January 2003. Measurement and social survey work carried out by the Building

Research Establishment during 1996/1997 provides the basis for applying limits at noise

sensitive premises, which range between the ‘mid fifties’ to the ‘mid sixties’ SNL25

Shots:30minutes.

The above research suggests that there is no fixed level for annoyance to occur.

Annoyance is, however, ‘unlikely’ below a level in the ‘mid fifties’: SNL25 Shots:30minutes and

‘highly likely’ above a level in the ‘mid sixties’ SNL25 Shots:30minutes as measured at the noise

sensitive premises. The SNL25 Shots:30minutes is the logarithmic average of the loudest 25

shots measured as a maximum (LAmax) in a 30 minute period.

From the predicted levels of noise for skateboarding activity taking place, the levels at

‘Byways’ on Mill Road and Toad Lodge on Newham Lane would be 65dB and 63dB

LAmax(fast), respectively equivalent to an SNL of 65 and 63dB. For the purposes of

calculation, these maximum source noise levels are assumed to be at a nominal height of

0.5 metres above the base of the skatepark to represent the use of ‘street scene’ parts of

the skatepark.

Using the above assessment method, this level represents one at which annoyance by the

skateboard noise levels at both the Mill Road and Newham Lane receptors would be at or

tending towards a level at which ‘complaints would be highly likely’.

On the basis of this assessment it is very likely that these maximum skateboard noise

levels would cause complaints from the residents living in Mill Road and Newham Lane.

5. DISCUSSION

The above methods of assessment have demonstrated that the BS4142 and Clay Target

Shooting impact predictions do not provide acceptable levels. As indicated previously, all

the three methods of assessment need be positive for the skatepark to be viable in terms

of noise impact.

Because of the low levels of background noise in the MPF, the BS4142 assessment

indicates ‘assessment levels’ of +17dB for the closest Mill Road properties and + 16dB for

those closest in Newham Lane. With these substantial excesses mitigation in the form of

earth bunding or fencing is not a viable option. The currently indicated bunding at


February 2013




approximately 1.5 metres provides no more than 5dB attenuation. To achieve the 16-

17dB attenuation required, would require bunds of a height which are unsustainable both

structurally and in terms of visual amenity.

Mitigation is not an option for the skatepark and these assessments are the strongest

indication that planning permission should not be granted for the skatepark.

The impact on the users of the Bowls Club and those in their allotments adjacent to the

skatepark will also be significant. The skatepark will give impulsive noise levels which are

different in character than current noises and significantly above the typical quiet

background within the MPF. This is likely to result in significant annoyance to these users.

5.1 National Planning Policy Framework [NPPF]

The NPPF was adopted on Tuesday 27th March 2012 and provides the following guidance

with regard to noise.

123. Planning policies and decisions should aim to:

• avoid noise from giving rise to significant adverse impacts on health and quality of

life as a result of new development;

• mitigate and reduce to a minimum other adverse impacts on health and quality of

life arising from noise from new development, including through the use of

conditions;

• recognise that development will often create some noise and existing businesses

wanting to develop in continuance of their business should not have unreasonable

restrictions put on them because of changes in nearby land uses since they were

established; and

• identify and protect areas of tranquillity which have remained relatively

undisturbed by noise and are prized for their recreational and amenity value for

this reason.

The NPPF in turn refers to the Noise Policy Statement for England [NPSE]. The NPSE was

issued in March 2010 by Defra with the following aims:

• avoid significant adverse impacts from noise;


February 2013




• mitigate and minimise its lesser but still adverse impacts;

• contribute to the improvement of health and quality of life through the effective

management of noise, for example through the promotion of quiet areas.

The NPSE utilises three concepts from toxicology to be applied to noise impacts. They are:

• NOEL – No Observed Effect Level. Below this level, there is no detectable effect on

health and quality of life due to the noise.

• LOAEL – Lowest Observed Adverse Effect Level. This is the level above which

adverse effects on health and quality of life can be detected.

• SOAEL – Significant Observed Adverse Effect Level. This is the level above which

significant adverse effects on health and quality of life occur.

In a case such as the proposed skatepark, the scheme would not result in lower noise

levels in the area.

Neither of these documents, however, provide any guidance as to assessment

methodology or levels at which the effects discussed can be noted. The skatepark would,

however, have a substantial impact on the environmental noise levels in the surrounding

area.

6. THE ATKINS AND ACOUSTIC DIMENSIONS REPORTS

6.1 Atkins Report of September 2012

Methodology

The methodology used by Atkins is similar to that used by ASA, that is reviewing both the

predicted LAeq levels of skateboarding with the LA90 background using BS4142 and

considering the impact of the maximum (LAmax) noise levels using the CIEH guidance in

relation to clay target shooting which has a similar ‘character’ to skateboard noise at

distance.

Distance to Receptors

The Atkins report quotes distances from the skatepark (Para 2.3) as 62 metres for Mill

Road properties and 80m for those on Newham Lane. These are thought to be the

distances from the closest edge of the skatepark to the property boundaries rather than


February 2013




the distances from the centre of the skatepark to a position approximately 3.5 metres

from the residential facades used by ASA. Since the current skatepark drawing STMF-

PSP01-rev C (16/11/2012) post-dates the Atkins report it is also not clear on what base

information they carried out their distance measurements.

Skateboard Source Measurements

The Atkins report, however, uses as its source data individual measurements of specific

activities normalised (corrected) to 1 metre (Table 6.2) and then calculates the level at

the receiver treating the skatepark as a ‘point source’ (i.e. a small point) rather than the

large area source that it is. This significantly overestimates the reduction to the receptors

from the skatepark and hence predicts levels at the receptors in Mill Road and Newham

Lane which are too low.

Based on research carried out into skateboard noise propagation at active skateparks,

ASA measurements have been made at sufficient distance to allow normal correction

procedures (6dB per doubling of distance) to be applied since they already contain the

required source corrections. Taking into account the overall effects of the different

distances used and the source corrections, the predicted impact and levels in the Atkins

report are about 5dB(A) lower than those of ASA for the LAeq and LAmax values.

Environmental Noise Measurements

Atkins carried out a manned environmental noise survey using 15 minute measurement

periods. No measurements were made at the beginning of the operational day or in the

morning, but were made into the evening when background noise levels would be

reducing. The measured background noise levels show a similar range to that discussed

in Table 3.1 of the ASA report and use correctly an arithmetic average level of 35/36dB:

LA90 for their assessment. This is consistent with the LA90: 35dB used in the ASA

assessment as a typical background noise.

Assessment of the Noise Impact

For the reasons indicated above, the Atkins skateboarding noise levels at the receptors in

Mill Road and Newham Lane are too low. The Atkins BS4142 assessment still, however,


February 2013




concludes that without mitigation ‘Complaints are likely’ at both the closest residential

locations.

With regard to the assessment of the SNL, however, Atkins incorrectly quote the CIEH

Clay Target document in their Para 7.4 ‘ ..the SNL predicted … at Newham Lane is just

within the recommended limit of 55-60dB.’. The document actually states in Section 6.1

that ‘At a shooting noise level below the mid 50’s dB(A) (i.e. 55dB) there is little evidence

of significant levels of annoyance at any site, whereas for levels in the mid to high 60’s (i.e.

greater than 65dB(A)) significant annoyance is engendered at the majority of sites.’ This is

qualified in Note 1 to of Appendix A.5.11 ‘Planning permission should not normally be

granted for a major (i.e. commercial) shoot if the mean shooting noise level exceeds 55dB

where the background noise (i.e. LA90) is less than 45dB.’ The background LA90 noise level is

usually significantly less than 45dB in the Memorial Park and the SNL limit should,

therefore, be around 55dB, i.e. not 55-60dB as quoted by Atkins.

Mitigation

On the basis of their assessments Atkins conclude in para 8.1 ‘.. the development of the

skatepark has the potential to impact on the amenity nearby noise sensitive receivers. And

in 8.2 ‘It is possible to reduce, but not necessarily eliminate, these impacts by employing a

combination of a number of mitigation measures, including control of hours of operation,

and appropriate earth bunding around the development.’ The bunding is in 8.3 ‘…likely to

be at least 1.5m in height (above the highest surface within the park) and surrounding the

extent of the skatepark, would offer some attenuation.’

The level of attenuation to be provided by the bunds is not specified in the report. The

bunds that Atkins had in mind at 1.5m above the highest point of the skatepark have not

been included in the drawings submitted with the planning application. The level in the

SW corner of the park at 13.31 is only 500mm below the top of the bund (at 13.81) on the

north side of the skatepark. Calculations carried out by ASA indicate that the attenuation

of the bund shown in the planning drawings is likely to be 5dB at best.

The current skatepark design is, therefore, likely to cause significant annoyance to the

closest residential areas.


February 2013




6.2 Acoustic Dimensions Report

Methodology

In their ‘executive summary’ Acoustic Dimensions (AD) indicate they have assessed the

noise from the proposed skatepark in relation to the current ambient (LAeq,T) noise and

the noise from football. This is a flawed comparison for the following reasons:-

i) For environmental noise, even that with a relatively broad frequency character

such as an extract fan, the LAeq needs to be assessed against the underlying

background LA90 – (the level exceeded for 90% of the time), not the ambient LAeq.

It is the noise impact during the 10% of each hour when the background noise is at

or below the LA90 that relates to its annoyance. This is standard procedure for all

local authorities. Comparison with the ambient LAeq would substantially

underestimate the true impact or likely annoyance. For noise with more a more

complicated character such as skateboarding noise, comparison with the

background noise is significantly more important.

ii) Comparing the noise from skateboarding with that from a football match

assumes they have the same character when clearly they do not. They are

completely different as anyone could identify. The annoyance from noise is

not only related to its level, but also to its ‘character’. So a noise source

which contains random harsh sounding bangs and crashes from skateboard

impact with ramps and grind rails, etc., will be much more annoying than

distant football noise which is mainly vocal with relatively subdued noises

during ‘kicking’ of the ball. The shouting human voice features significantly

in football but not in skateboarding. Para 4.2.7 of the WHO Guidelines

recognises this as ‘It is emphasised that for intermittent noise [such as the

skateboarding activities] it is necessary to take into account the maximum

[i.e. the LAmax] sound pressure level as well as the number of events.’. The AD

report contains no mention of the maximum noise levels during

skateboarding or their impact, which are the major sources of annoyance to

residential occupants.

iii) Another factor that is directly related to the annoyance from a noise source

is its duration and how often it occurs. To compare a football match which


February 2013




lasts, say, once each week 90 minutes with skateboarding noise which could

potentially occur between 08:30 to 22:30hrs every day during the summer

months (when there would be no football) is clearly a flawed hypothesis. A

comparison would be if a helicopter flew over your house at low level once a

week, you wouldn’t be annoyed by it. If it happened five or six times in a

day, you would probably begin to be annoyed. If this happened every day of

the week, you would be highly annoyed.

AD’s assertion that ‘The occurrence of maximum occupancy will be outside

school hours. Usage of the skateboard facility will be very low during school

hours, in the early morning and after dark.’ is clearly flawed as the schools

have at least 20% of each year on holiday. Even during the Easter holidays

when football is being played, it accounts for 1.7% of the likely period over

which skateboarding could take place at that time of year and the

football/skateboard noise comparison is less than dubious.

In their ‘Executive Summary’ AD confirm that when assessed under BS4142 complaints

would be deemed likely. They then state that it is not applicable because the site has a

very low background noise level. This is a misreading and misinterpretation of BS4142

which actually states in section 1 ‘Scope’, ’The method is not suitable…..or when the

background noise and rating levels are both very low.’ It defines ‘very low’ as background

levels below 30dB and rating levels below about 35dB. As previously discussed,

background noise levels measured by Atkins, ASA and AD(Table in Para 2.3.1) vary

between 33-38.5dB: LA90,15m. The ‘rating level’ from Atkins and ASA is between 51.2 –

52dB. These are both significantly above the BS4142 threshold meaning it is applicable

for this assessment. Whilst it is specifically used for industrial noise it does allow the

assessment of impact and impulsive noises against the underlying background and, as the

court ruled in Richardson v Devizes Town Council and accepted by Atkins in their report, is

a ‘reasonable’ and informative comparison in the absence of any specific guidance in

relation to skateboard noise.

In para 5.9 of the AD report they refer to ‘further discussion in Appendix A’ in relation to

BS4142 and the CIEH document. Unfortunately, Appendix A does not contain any further

discussion.


February 2013




Distance to Receptors

The AD report carries out calculations to thirty two residential receptors, although there

is no details of their distances from the new skatepark save a mention in Para 5.5 of

‘..receiver 32 ≈ 80m’. From the site plan in Para 4.1.3 this location is at the rear

boundaries of the closest properties in Mill Road.

Skateboard Source Measurements

In their Appendix C, AD report measurements made at distances of 2 metres from

skateboarders in their table on Page 25. The table gives measurements in relation to the

LAeq over a variety of different time intervals and the SEL but no LAmax values. They then

state (Para 3.1-Appendix C) ‘We have used a point source propagation method to

calculate noise from proposed skateboarding.’ They go on to say in Para 3.1.2 Our

calculations…….based on guidance given in ISO 9623-2: 1996…’. It is presumed they mean

ISO 9613-2 as ISO 9623 relates to ‘Metal pipe/adaptor fittings’.

In a similar way to the Atkins report, instead of just measuring noise from busy

skateparks, at a distance, they construct a model using their measurements and an

assumed activity pattern and assume that only 50% of the users are skateboarders whilst

the other 50% are, the much quieter uses such as scooters and BMX bikes. There is no

noise data provided for these uses. As the skatepark is a large area source, this

overestimates the reduction to the receptors from the skatepark and hence predicts

levels at the receptors in Mill Road and Newham Lane which are too low.

Environmental Noise Measurements

The ‘current’ ambient noise that AD measured, as shown in their Para 3.1, indicate a ‘Log

average LAeq,T’ based on only four 15 minute measurements between 09:00 and 15:00

hours of 53dB for Mill Road and 46dB for Newham Lane. This is an inadequate number of

measurements over too short a period to make any informed judgement as the typical

levels over the skateboarding day. It should also be noted that ‘log averaging’ provides a

level which is dominated by the highest value measured so, in their second graph on page

6, the three measurements they made at about 43dB: LAeq,15m are skewed by the last

measurement at 50dB: LAeq,15m to give a value of 46dB, whereas 43dB is more the typical


February 2013




value as can be seen in our Time History AS7317/TH1 measured at the Newham Lane

properties.

In the graph in Para 3.5, their ambient LAeq is further skewed by using ‘Site wide ambient

and background noise levels’. This further elevates their ambient and assessment levels

by skewing them towards the louder measured levels on Mill Road so that when

subsequently reviewed against ‘football’ noise levels and ‘skatepark’ noise levels in 4.2.4

and 4.3.1 they seem about the same as the current ambient levels.

The graphs in AD’s Para’s 4.2.4 and 4.3.1 report ‘Upper and Lower Log Ave (log average)

LA90 noise levels. This is a fundamental technical error since LA90 values cannot be

averaged logarithmically as they are statistical parameters, they can only be

arithmetically averaged i.e. added up and divided by the number of values. It is also not

clear, therefore, what the ‘Upper and Lower..’ values mean, as the values in their

Appendix B in Para 2.3 have a much wider range than the values in the two graphs.

Assessment of the noise Impact

The AD Introduction states in Para 1.3 ‘We have completed our assessment based on an

appropriate methodology agreed with Horsham District Council.’ In Para 1.4 they state.

’We compare noise from the proposed skateboarding facility with ambient noise (i.e.

LAeq,T) and with noise from football matches played at the Memorial Playing Fields.’

Any assessment method which does not consider the impact of maximum skateboard

noise levels as well as the LAeq against the underlying background LA90 noise level and the

frequency of occurrence is flawed, since it is these characteristics which dictate the

probable levels of annoyance to nearby residential.

Mitigation

In Para 6.1 and 6.2 AD note that the currently indicated bund does ‘..not have a

significant (effect ?) on our calculations of noise at residential properties’. This is because

in their Para 4.1.4 they state that ‘Receiver locations were chosen 3 m off the ground

corresponding to first floor (bedroom) windows. Our calculations assume a clear line of

sight between source and receiver locations…’. At this receive height it is agreed the

bunds would have no effect. At a normal daytime receive height, of say, 1.5 metres,


February 2013




however, the effects at the closest properties would be as detailed previously in this

report, with the bunds giving about a 5dB reduction in propagated noise. To achieve the

16-17dB attenuation required, would require bunds of a height which are unsustainable

both structurally and in terms of visual amenity.

In their Para 6.4 AD state that ‘In our opinion earth bunds are not required to provide

additional reduction in noise from the proposed skateboarding facility. Noise levels will be

suitably low that disturbance is unlikely.’. This opinion is based on a novel but flawed

assessment method.

The current skatepark design is, in reality, likely to cause substantial annoyance to the

closest residential areas.

7. SUMMARY AND CONCLUSIONS

7.1 ��

Noise measurements of skateboarding on a concrete bowl skatepark have been used to

predict the possible noise impact of the proposed new skatepark at the Memorial Playing

Field at Steyning in West Sussex.

There is no directly specific guidance as to the impact of skateboarding noise on the

occupants of residential premises, but there is relevant guidance given by British Standard

BS4142: 1997 Rating industrial noise affecting mixed residential and industrial areas the

World Health Organisation document Guidelines on Community Noise: 1999 and the

document Clay Target Shooting, Guidance on the Control of Noise published by the

Chartered Institute of Environmental Health Engineers (CIEH) in January 2003 which has

been accepted in landmark noise cases and is used by many acoustical consultants and

local authorities for new skateparks.

The most sensitive residential properties are some 90-110 metres from the centre of the

proposed skatepark location. From the predicted noise levels at these residences and

long term measurements of the background and ambient noise levels, the likely impact of

the skateboarding noise on the residential amenity has been considered using the three

documents referred to above. This initial evaluation procedure has been used

successfully at other currently operational skateparks.


February 2013




The conclusion of the analysis within the report is that the current skatepark design is

likely to cause substantial annoyance to people living in the closest residential areas.

7.2 ��

The methodology used by Atkins is similar to that used by ASA, that is reviewing both the

predicted LAeq levels of skateboarding with the LA90 background considering the impact on

the underlying background noise and the impact of the maximum (LAmax) noise levels

using the CIEH guidance in relation to clay target shooting, although it misreads the

guidance in relation to noise levels and likely annoyance. Their prediction of the source

noise also underestimates the true noise impact at receptors.

The Atkins report concludes that ‘The skatepark has the potential to impact on the

amenity of nearby noise sensitive receivers.’, and ‘Any skatepark installed at this location

should include the provision of mitigation measures in an effort to minimise these

impacts.’ They then describe the mitigation measures as limiting the opening hours so as

to close by 8:30pm and ‘Carefully designed earth bunding required around the park at

least 1.5m higher than the highest point within the park.’ Reviewing the SPC drawing the

indicated bunding will not achieve the requirements set out by Atkins.

7.3 � ��

The Acoustic Dimensions ‘Introduction’ states in Para 1.3 ‘We have completed our

assessment based on an appropriate methodology agreed with Horsham District Council.’

In Para 1.4 they state. ’We compare noise from the proposed skateboarding facility with

ambient noise (i.e. LAeq,T) and with noise from football matches played at the Memorial

Playing Fields.’ This is a flawed comparison because:-

• Even broadband noise sources such as an extract fan are required to be reviewed

against the underlying background noise LA90 and typically to lower than this by 5-

10dB. Comparison with the average ambient noise level (LAeq) on a Saturday and

during a football march is neither logical nor representative of the likely impact

on nearby residents.

• Comparing the noise from skateboarding with that from a football match

assumes they have the same ‘character’ when clearly they do not. Character is a

significant indicator in human annoyance by noise.


February 2013




• The comparisons made by Acoustic Dimensions do not consider for how long and

how often the noise is produced. These again are major factors in human

annoyance. If the football match occurred every day of the year over most of the

daytime period, as the skatepark noise can potentially, then this would certainly

be considered annoying by nearby residents. Once a week and only in the

winter, when residents are not in their gardens, engenders a much higher level of

tolerance to noise.

The report like the Atkins report derives their source noise levels for skateboarding, using

measurements made close to individual skaters (2 metres stated). For a moving source,

however, any recorded distance can only be an estimate introducing the first potential for

error. They then calculate the noise to distant receptors for a derived scenario of many

skateboarders on a skatepark using ‘.. a point source propagation method..’. This is

incorrect, as the skatepark is a plane source whose area will mean that noise levels at

distance are further underestimated. The noise impact is also underestimated as a result.

In their Para 6.4 AD state that ‘In our opinion earth bunds are not required to provide

additional reduction in noise from the proposed skateboarding facility. Noise levels will be

suitably low that disturbance is unlikely.’. This opinion is based on a flawed assessment

method.

The current skatepark design is, in reality, likely to cause substantial annoyance to people

living in the closest residential areas.

��

Alan Saunders

ALAN SAUNDERS ASSOCIATES

Location 1: ‘Byways’, Mill Road

Location 2: Toad Lodge, Newham Lane

Proposed Skate Park Location

Environmental Noise Monitoring

Position

90 meters

100 meters

Project:

Steyning Skatepark, BN44 3LE

Title:

Indicative Site Plan�

Figure:

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Project: AS7313 Memorial Playing Field, Steyning Skatepark

Newham Lane Impact

Noise Impact Assessment as 'base' design

BS4142 Assessment

Receptor Distance 110 m

LAeq,1h for Skateboarding 55 dB @ 40m

Distance Loss to 110m -9 dB

Acoustic Screening 0 dB

LAeq,1hr at Receiver(specific noise level) 46 dB

Character Correction 5 dB

Rating Level 51 dB

Background LA90 level 35 dB

Assessment Level 16 dB * rounded to nearest dB

Conclusion

WHO Guidelines Assessment

Skate Boarding 09:00 - 21:00hrs 12 hours

Worst case continuous 7 hours out of 16hr Daytime

7 hours @ 46 dB(A)

9 hours @ 0 dB(A)

Correction -4 dB

Acoustic Screening 0dB

LAeq,16hr= 42 dB(A) * rounded to nearest dB

Clay Target Assessement

LAmax for Bowlpark

LAmax at Receptor

Acoustic Screening

LAmax at Receptor

Comment LAmax(SNL)>55dB<65dB

Calculation AS7313/C1

Tending towards 'Complaints being

highly likely'

Complaints very likely

Toad Lodge,Newham Lane

Not OK

Skating for 7

out of 16 hours

71dB @ 45m

63dB @ 110m

0dB

63 dB

OK for day and evening (40-45dB) no

moderate annoyance

Project: AS7313 Memorial Playing Field, Steyning Skatepark

Mill Road Impact

Noise Impact Assessment as 'base' design

BS4142 Assessment

Receptor Distance 90 m

LAeq,1h for Skateboarding 55 dB @ 40m

Distance Loss to 90m -7 dB

Acoustic Screening 0 dB

LAeq,1hr at Receiver(specific noise level) 47 dB

Character Correction 5 dB

Rating Level 52 dB

Background LA90 level 35 dB

Assessment Level 17 dB * rounded to nearest dB

Conclusion

WHO Guidelines Assessment

Skate Boarding 09:00 - 21:00hrs 12 hours

Worst case continuous 7 hours out of 16hr Daytime

7 hours @ 47 dB(A)

9 hours @ 0 dB(A)

Correction -4 dB

Acoustic Screening 0dB

LAeq,16hr= 44 dB(A) * rounded to nearest dB

Clay Target Assessement

LAmax for Bowlpark

LAmax at Receptor

Acoustic Screening

LAmax at Receptor

Comment LAmax(SNL)>55dB<65dB

Calculation AS7313/C2

Tending towards 'Complaints being

highly likely'

Complaints very likely

'Byways', Mill Road

Not OK

Skating for 7

out of 16 hours

71dB @ 45m

65dB @ 90m

0dB

65 dB

OK for day and evening (40-45dB) no

moderate annoyance

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