Azura-Edo Independent Power Plant Environmental Impact ... - IFC

The values in Table 7.13 will therefore form the basis of assessing significance
for the construction and operational phases.
Table 7.14
Impact Assessment Methodology for Residential Receptors
Construction and
Decommissioning
Noise
Major Moderate Minor Negligible Not significant
Noise level >15
dB above
criteria
Operational Noise Noise level
between >10 dB
above criteria
Noise level
between 10 to
15 dB above
criteria
Noise level
between 5 to 10
dB above
criteria
Note: Criteria for construction is 70 dB LAeq, 1hr
Daytime: 07:00 to 22:00; night time: 22:00 to 07:00
Noise level up
to 10 dB above
criteria
Noise level
between 3 and
5 dB above
criteria and
above baseline
Noise level up
to 5 dB above
criteria
Noise level
below criteria
but above
baseline < 3dB
Noise level
below criteria
Noise level > 10
dB below
criteria and
below baseline
These operational noise criteria have been used on numerous international
development projects and although the not have a specific legal basis, they are
considered as best practice with respect to significance impact rating of noise.
Construction sites, however, have special characteristics compared with other
major noise generators. Construction is generally undertaken in the open, is
usually of a temporary duration, and varying levels of noise are produced by
several different types of noise sources. Noise levels created by construction
equipment can vary greatly and depend on factors such as type of equipment,
the specific model, the operation being performed, duration of the activity,
and the condition of the equipment.
Construction equipment operates in two modes, namely stationary and
mobile. Stationary equipment operates in one place for one or more days at a
time, with either fixed power operation (pumps, generators, compressors) or a
variable noise operation (pile drivers, pavement breakers).
There are no standardised criteria for assessing construction noise and
associated impacts, and consequently such criteria must be determined on a
project specific basis. The Project construction noise criteria should take into
account the existing noise environment, the absolute noise levels during
construction activities, and the receptor land use. The following reviews of
recognised construction noise guidelines provide guidance to develop suitable
construction noise criteria. For construction, noise criteria of 70 dB LAeq,1hr
are set to take account of the fact that it is temporary, and to acknowledge
that construction work by its very nature is noisy and a lower, strictly
enforced criteria, can limit development.
Existing Noise Environment
Noise measurements were taken of the existing noise environment during the
wet and dry seasons (and are presented in Chapter 4). The background noise
levels could not be accurately determined due to the prevalence of
AZURA EDO IPP
7-31
DRAFT EIA REPORT