Step 1 - Location of the Most Affected Noise Sensitive Receiver (NSR)

The NSR which will be most affected by noise from the percussive piling shall be identified.

For the purpose of this Technical Memorandum any domestic premises, hotel, hostel, temporary housing accommodation, hospital, medical clinic, educational institution, place of public worship, library, court of law, performing arts centre or office building shall be considered to be a NSR. Any other premises or place, not being in the nature of industrial premises, which is considered by the Authority to have a similar sensitivity to noise as the premises and places above shall also be considered to be a NSR. Any premises or place shall, however, be considered to be a NSR only when it is in use for its intended purpose.

Step 2 - Determination of the Acceptable Noise Level (ANL) for the Noise Sensitive Receiver (NSR)

The Authority shall determine the appropriate ANL for the NSR under consideration from Table 1. If Table 1 is not directly applicable to the NSR under consideration the Authority may make use of such ANL as it considers appropriate.

If in the opinion of the Authority the NSR will be materially affected by noise from percussive piling associated with more than one CNP, the Authority may make such correction to the ANL as it considers appropriate having regard to standard acoustical principles and practices.

Step 3 - Sound Power Levels for Percussive Piling

The sound power level of each of the percussive piling units included in the CNP application shall be obtained from Table 2 having regard to the piling method and pile type combination. If any piling method and pile type combination included in the CNP application does not appear in Table 2 the Authority may make use of such sound power level as it considers appropriate.

Step 4 - Summation of Noise Levels

The sound power levels obtained in Step 3 shall be summed logarithmically in accordance with Table 3 to obtain a total sound power level.

Step 5 - Distance Attenuation

The plan distance or, where appropriate, the slant distance between the NSR and the pile location nearest to the NSR shall be determined.

The position of the pile location nearest to the NSR shall be selected having regard to any pile layout drawing supplied by the CNP applicant. If no such drawing is supplied to the Authority the position shall be taken to be the position on the piling zone boundary nearest to the NSR.

The appropriate correction factor for distance attenuation shall be obtained from Table 4. This correction factor shall be subtracted from the total sound power level obtained in Step 4 to give the Predicted Noise Level (PNL) at the NSR.