ENVIRONMENTAL RESOURCES MANAGEMENT APCL – ABERNEDD POWER PLANT 8-1 8 NOISE AND VIBRATION 8.1 SUMMARY OF RESIDUAL IMPACTS No significant residual impacts for the construction and operation of the proposed CCGT power plant development are expected as these will be mitigated through design and planning conditions as appropriate. A temporary residual noise impact as a result of road traffic noise from personnel vehicles associated with the construction of the scheme is expected on residents living alongside the A48. This will only occur in the hours when construction personnel will be travelling to and from site, during the peak month of the 30 month Stage 1 construction period. During commissioning there will be short periods between the hours of 09:00hrs and 17:30hrs when pipelines will be subjected to purging flows and safety valves tested. These operations are short-term in duration, but can cause high levels of noise and therefore result in temporary residual noise impacts. These activities will take place occasionally and will last only a few hours at a time. No significant construction or operational vibration impacts are expected. 8.2 INTRODUCTION This chapter considers the potential for noise and vibration impacts associated with the construction and operation of the proposed power station at the Baglan Bay Energy Park. The site is adjacent to the GE power station and the M4 motorway. The proposed scheme will introduce a new and permanent source of noise in the area. 8.3 LEGISLATION AND POLICY REVIEW The aim of noise policy within Wales is to protect individuals from excessive noise levels both in the workplace and when at home. It has been recognised that noise can cause annoyance and can lead to sleep disturbance and potentially other adverse health effects. Legislation has aimed to address this. Regulations, mainly at EU level, have set maximum sound levels for vehicles, aeroplanes and machines. More recently the European Commission has requested mapping of noise levels and the development of Action Plans to address noise problems where necessary, including preservation of quiet areas. At national level, the Department of Environment, Food and Rural Affairs (DEFRA) has been developing an Ambient Noise Strategy giving policy guidance on transportation and industrial noise. Planning Guidance (TAN 11) has also been important in promoting ways of reducing noise problems in the future. Some local
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ENVIRONMENTAL RESOURCES MANAGEMENT APCL – ABERNEDD POWER PLANT
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8 NOISE AND VIBRATION
8.1 SUMMARY OF RESIDUAL IMPACTS
No significant residual impacts for the construction and operation of the
proposed CCGT power plant development are expected as these will be
mitigated through design and planning conditions as appropriate.
A temporary residual noise impact as a result of road traffic noise from
personnel vehicles associated with the construction of the scheme is
expected on residents living alongside the A48. This will only occur in the
hours when construction personnel will be travelling to and from site,
during the peak month of the 30 month Stage 1 construction period.
During commissioning there will be short periods between the hours of
09:00hrs and 17:30hrs when pipelines will be subjected to purging flows
and safety valves tested. These operations are short-term in duration, but
can cause high levels of noise and therefore result in temporary residual
noise impacts. These activities will take place occasionally and will last
only a few hours at a time.
No significant construction or operational vibration impacts are expected.
8.2 INTRODUCTION
This chapter considers the potential for noise and vibration impacts
associated with the construction and operation of the proposed power
station at the Baglan Bay Energy Park. The site is adjacent to the GE power
station and the M4 motorway. The proposed scheme will introduce a new
and permanent source of noise in the area.
8.3 LEGISLATION AND POLICY REVIEW
The aim of noise policy within Wales is to protect individuals from
excessive noise levels both in the workplace and when at home. It has been
recognised that noise can cause annoyance and can lead to sleep
disturbance and potentially other adverse health effects. Legislation has
aimed to address this. Regulations, mainly at EU level, have set maximum
sound levels for vehicles, aeroplanes and machines. More recently the
European Commission has requested mapping of noise levels and the
development of Action Plans to address noise problems where necessary,
including preservation of quiet areas. At national level, the Department of
Environment, Food and Rural Affairs (DEFRA) has been developing an
Ambient Noise Strategy giving policy guidance on transportation and
industrial noise. Planning Guidance (TAN 11) has also been important in
promoting ways of reducing noise problems in the future. Some local
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authorities also produce their own local planning guidance as part of their
development plans. Relevant policies are discussed in greater detail in
Section 8.4 below.
8.4 ASSESSMENT SCOPE AND METHODOLOGY
8.4.1 Introduction
The approach to this assessment has been discussed and agreed in
consultation with Neath and Port Talbot County Borough Council. The
scope of this assessment, and the assessment methodology and criteria are
discussed below.
8.4.2 Scope of Assessment
The assessment included the following tasks:
• defining noise sensitive receptors (NSRs) in consultation with NPTCBC;
• defining the baseline noise environment by measurement at
representative NSRs;
• assessing construction noise and vibration impacts at representative
NSRs;
• assessing road traffic noise impacts from construction and operation;
and
• defining acceptable operational noise and vibration levels for the
proposed development.
8.4.3 Construction Assessment Methodology and Criteria
Advice and guidelines to local planning authorities and developers on
construction noise in the UK can be found in British Standard BS 5228 (1)
and Advisory Leaflet (AL) 72 (2). AL 72 is out of print, but remains as a
paper giving guidance on acceptable levels of construction noise.
BS 5228 Part 1 does not specify suitable daytime noise levels from
construction sites, but lists a number of factors that might affect the
acceptability of noise and vibration from construction sites. These factors
are:
(1) British Standard BS 5228: 1997 ‘Noise control on construction and open sites’. BSI. 1997. (2) Advisory Leaflet 72. ‘Noise control on building sites’. Department of the Environment. 1976.
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• site location;
• existing ambient noise levels;
• duration of site operations;
• hours of work;
• attitude to site operator; and
• noise and vibration characteristics of the work.
Although BS 5228 does not propose noise standards for daytime periods, it
suggests that acceptable noise levels in the evening (1900 - 2200 hours) may
need to be 10 dB(A) lower than daytime levels. AL 72 gives advice on
preferred maximum levels of construction site noise at residential locations
during daytime hours (0700 – 1900 hours). Since the criterion of speech
interference forms the basis of the recommendations within AL 72, they can
be taken as applicable to commercial buildings as well as residential
properties. The leaflet states that the noise level outside the nearest
occupied room should not exceed:
• 75 dB(A) in urban areas near to main roads in heavy industrial areas; or
• 70 dB(A) in rural, suburban and urban areas away from main road
traffic and industrial noise.
These levels are generally taken as being facade LAeq, period (1) and will be
used to assess potential construction noise impacts.
Local authorities have powers under the Control of Pollution Act 1974 to
control noise from construction sites. These powers do not refer to fixed
noise limits but instead allow for the enforcement of ‘best practicable
means’ (2) to reduce or counteract the effects of the noise.
It is assumed that the construction work will take place over a five day
working week, with the maximum working hours of 0700 to 1900 hours.
A Code of Construction Practice (CoCP) will set working hours and noise
control measures, and will be agreed with NPTCBC prior to construction
work commencing.
8.4.4 Operational Noise Assessment Methodology and Criteria
Overview
Noise from developments is assessed in two ways:
• by comparing the predicted level of noise from the development
against absolute noise standards, such as those that indicate likely
(1) LAeq is defined as the notional steady sound level which, over a stated period of time, would contain the same
amount of acoustical energy as the A-weighted fluctuating sound measured over that period. (2) Defined in Section 72 of the Control of Pollution Act 1974.
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annoyance and/or disturbance of everyday activities; and/or
• by considering the change in ambient noise that will occur with the
development in operation.
Criteria which may be applicable for operational noise from the proposed
development, including road traffic noise are discussed below.
Technical Advice Note (TAN) 11
Technical Advice Note (TAN) 11(1) provides guidance to local authorities
on how the planning system can be used to minimise the adverse impact of
noise without placing unreasonable restrictions on development or adding
unduly to the costs and administrative burdens of business. It outlines
some of the main considerations which local planning authorities should
take into account when determining planning applications for development
which will either generate noise or be exposed to existing noise sources.
TAN 11 also makes reference to other guidance and criteria applicable for
different sources of noise such as industrial and commercial developments,
roads and railways.
TAN 11 states that BS 4142 (2) is the most appropriate methodology to
assess noise from industrial developments and from fixed plant associated
with the proposed developments.
British Standard BS 4142
The test that is generally applied to determining the level of noise of an
industrial nature likely to give rise to complaints from persons living in the
vicinity is given in British Standard BS 4142.
BS 4142 describes a method for determining industrial and background
noise levels outside residential buildings and for assessing whether the
industrial noise is likely to give rise to complaints from the occupants.
The BS 4142 assessment methodology involves the following procedure:
• the background (LA90) noise level (BNL) in the absence of the noise
source is measured outside the noise-sensitive receptor;
• the noise level from the source is then quantified, by prediction or
measurement, at a noise sensitive receptor as an LAeq (using the
procedures set out in the standard);
(1) Planning Guidance (Wales). Technical Advice Note 11, 1997. (2) British Standard BS 4142: 1997 'Method for Rating industrial noise affecting mixed residential and industrial areas'
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• the noise level is corrected, if appropriate, for duration and character,
with the corrected noise level being termed the rating level and
expressed as an LAeq; and
• the rating level is then compared with the BNL (LA90) for the area.
The interpretation of the difference between the rating level and the BNL is
shown in Table 8.1 below.
Table 8.1 Interpretation of Noise Level Difference
Difference in Noise Level (dB) Significance
Around +10 Complaints are likely
Around +5 Marginal
More than – 10 Positive indication that complaints are unlikely
BS 4142 requires that daytime assessments are based on the highest LAeq
from the noise source over a period of 1 hour, while at night an assessment
period of 5 minutes is specified.
8.4.5 Road Traffic Noise
The proposed development may alter the traffic flows on the local
highways leading to changes in road traffic noise. The road traffic noise
assessment takes into consideration the following guidance as appropriate:
• DMRB (1) to identify where changes in road traffic will require a more
detailed assessment; and
• CRTN (2) to assess the actual change in road traffic noise as a result of
the project.
An increase in traffic flow of 25% (or reduction by 20%) is generally needed
to increase noise levels by 1 dB(A). A change of 1 dB(A) is only perceptible
in controlled conditions, and a change of 3 dB(A) is generally accepted as
the minimum perceptible under normal conditions. For heavy goods
vehicles an increase of around 5% is generally needed to increase noise
levels by 1 dB(A).
Flow changes of this size are not expected to give rise to perceptible noise
changes under normal listening conditions and have been adopted as the
scoping criterion for road traffic noise.
These standards apply to permanent noise changes and higher changes are
likely to be acceptable during construction.
(1) Design Manual for Roads and Bridges (DMRB). Volume 11, Section 3, Part 7 'Traffic Noise and Vibration'. 1994 (2) Department of Transport / Welsh Office Memorandum 'Calculation of Road Traffic Noise' (CRTN), 1998
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8.4.6 Vibration Assessment Criteria
Human Exposure
The assessment of vibration follows the guidance set out in British
Standard BS 6472 (1). This standard provides a method to assess
disturbance from vibration.
The vibration dose value (VDV) levels, given in BS 6472 at or below which
the probability of ‘adverse comment’ is low are as follows:
• daytime (0700–2300 hours): 0.4 m/s1.75; and
• night-time (2300–0700 hours): 0.13 m/s1.75.
Building Damage Arising from Vibration
British Standard BS 7385 (part 2) (2) provides vibration criteria relating to
building damage and advice on acceptable levels of vibration in structures.
Limits for primarily transient vibration (eg from piling works or train pass-
by) above which cosmetic damage could occur are as follows:
• reinforced or framed buildings: 50 mm/s PPV; or
• un-reinforced or light framed buildings: 15 mm/s PPV.
8.5 BASELINE CONDITIONS
8.5.1 Noise Sensitive Receptors
The site of the proposed CCGT power plant development is located to the
north west of the Baglan Bay Energy Park and adjacent to the existing GE
power station. The village of Baglan is located on a hill to the north east of
the M4 motorway, overlooking the site. The A48 and M4 separate the site
and the village of Baglan. A full description of the development is given in
Chapter 2. The site location, NSRs and noise measurement locations are
illustrated in Figure 8.1.
A description of the NSRs and noise measurement locations are given
below.
• Location 1: Brahams Avenue. Representative of residential properties
in Sandfields to the south of the site, approximately 465 m from the
closest site boundary.
(1) BS 6472: 1992 'Guide to Evaluation of human exposure to vibration in buildings (1 Hz to 80 Hz). (2) BS 7385-2: 1993 ‘Evaluation and measurement for vibration in buildings – Part 2: Guide to damage levels from
groundborne vibration’.
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• Location 2: Affendale. Representative of a recent residential
development situated between Sandfields and Baglan Moors to the
south of the site, approximately 610 m from the closest site boundary.
• Location 3: Church Street. Representative of properties in Briton Ferry
and Llansawel to the north east of the site, approximately 320 m from
the closest site boundary (re-routed pipe), and 1495 m from the main
works (CCGT plant). There is also a travellers’ site at this location
which may experience potential noise impacts associated with the
construction of the water works and re-routing of the water pipe.
• Location 4: Sunny Mount. Representative of properties to the east of
the site, located on the far side of the M4 motorway, approximately
1120 m from the closest site boundary.
8.5.2 Baseline Noise Environment
Measurements were taken in accordance with BS 4142 using a Type 1
sound level meter placed on a tripod at a height of 1.5m, and calibrated
prior to use. No significant (± 0.5dB) calibration drift was noted.
The surveys were undertaken during the weekends of May 25th and June
2nd, 2007. Full details of the survey and a glossary of acoustic terms are
included in Annex B.
Ambient noise levels at each location were found to vary, and in general
the lowest ambient levels recorded in each time period are used in the
assessment. A summary of the measured baseline noise levels are
presented in Table 8.2 below.
Table 8.2 Summary of Measured Baseline Noise Levels (free-field), dB
Sound Pressure Level (dB) Measurement
Location (See
Figure 8.1) Daytime (1)
LAeq, 10 mins Night-time (2)
LAeq, 10 mins
LAmax, range of 10 min
samples
1 - Brahams Avenue 56 46 69-83
2 – Affendale 51 44 69-80
3 - Church Street 55 47 68-79
4 - Sunny Mount 54 47 72-87
Ambient noise at Brahams Avenue and Affendale consisted of road traffic
noise from local roads, the A48 and M4, and operational noise from the GE
power station. Ambient noise at Church Street and Sunny Mount was
dominated by road traffic noise from the A48 and the M4 along with
operational noise from the GE power station, perceptible during gaps in the
traffic.
(1) Daytime is defined as 0700 – 2300 hours (2) Night time is defined as 2300 - 0700 hours
