Table 3.3     Noise Monitoring Parameters, Duration and Frequency

              Contract No.

Monitoring Stations

Parameter

Duration

Frequency

Measurement

ND/2019/01

CP-KTN NMS5

L10(30 min.) dB(A)

L90(30 min.) dB(A)

Leq(30 min.)dB(A)

(as six consecutive Leq, 5min readings)

0700-1900 hrs on normal weekdays

Once per week

Free-field[1]

ND/2019/06

CP-FLN-NMS1

Façade

Remarks:

[1]: Correction of +3dB (A) for Free-field Measurement.

[2]: A-weighted equivalent continuous sound pressure level (Leq). It is the constant noise level which, under a given situation and time period, contains the same acoustic energy as the actual time-varying noise level.

L10 is the level exceeded for 10% of the time. For 10% of the time, the sound or noise has a sound pressure level above L10.

L90 is the level exceeded for 90% of the time. For 90% of the time, the noise level is above this level.