Attachment 5 - Environmental Noise Assessment

LAFast
The noise level in decibels, obtained using the A frequency weighting and the F time weighting as
specified in AS1259.1-1990. LAFast is used when examining the presence of modulation.
LAmax
The LAMax level is the maximum A-weighted noise level throughout a specified measurement.
LAmax assigned level
The LAmax assigned level describes a level which is not to be exceeded at any time.
LAPeak
The LAPeak level is the maximum reading (measured in decibels) during a measurement period,
using the A frequency weighting and P time weighting AS1259.1-1990.
LASlow
A LASlow level is the noise level (measured in decibels) obtained using the A frequency weighting and
S time weighting as specified in AS1259.1-1990
Major Road
A Major road has an estimated average daily traffic count of more than 15,000 vehicles.
Maximum Design Sound Level
Maximum Design Sound Level is the level of noise beyond hearing range of most people occupying
the space start, become dissatisfied with the level of noise.
Modulating Noise
A modulating source is an audible, cyclic and regular source. It is present for at least 10% of a
measurement period. The quantitative definition of tonality is:
a fluctuation in the discharge of noise which;
         a) is more than 3 dB LA Fast or is more than 3 dB LA Fast in any one-third octave band;
         b) is present for at least 10% of the representative
One-Third-Octave Band
One-Third-Octave-Band are frequencies that span one-third of an octave which have a centre
frequency between 25 Hz and 20 000 Hz inclusive.
Representative Assessment Period
Representative Assessment Period describes a period of time not less than 15 minutes, and not
surpassing four hours. It is determined by an inspector or authorised person to be suitable for the
assessment of noise emissions.
Reverberation Time
Reverberation time refers to an enclosure for a sound of a specified frequency or frequency band as
well as the time that would be necessary for the reverberantly decaying sound pressure level in the
enclosure to decrease by 60 decibels.


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