Prediction And Control Of Air Overpressure From Blasting In Hong Kong
An English language translation of Professor Wang’s comments is given below:
1. GB 6722-2003, Clause 6.8.3 on “Noise Control”. This is about the noise that is audible, that it does not include noise that is of low frequencies (<20 Hz) and ultra high frequencies. In the measuring equipment, there is a filter that would filter out the low frequencies parts, and we normally denote such measurements by dB. Clause 6.8.3.1 of the Regulations states that the “Blasting noise is a kind of intermittent impulsive noise. For urban blasting, every impulsive noise should be controlled to less than 120 dB”. The unit of measurement here should be dBA.
The air overpressure here means the peak value for the full frequency band and the unit of measurement is dBL (linear scale). This can also be represented as pressure value in Pa. Clause 6.3.2 states that safe allowable standard of air overpressures: for human is 2000 Pa, and for structures the values are given in Table 6....