Survey procedures

Requirements for conducting construction noise measurements are provided in NZS 6801, NZS 6802 and NZS 6803. The following provides some additional practical guidance, but does not reproduce the full requirements of the standards.

Survey planning:

• Liaise with the site manager and obtain the construction schedule. Choose a time(s) for the survey during representative activities
• If conducting night-time monitoring, visit the site in daylight first
• Arrange access to make measurements outside neighbouring buildings
• Print a high resolution aerial photograph of the works and the nearest neighbours
• Print survey sheets
• Check the equipment and calibration records
• Check the weather forecast

Measurement positions:

• One metre from the most exposed façade of neighbouring buildings
• 1.2 to 1.5 metres above the floor levels of interest
• If the above location is not practicable then a location should be used either closer to the works, or possibly inside the neighbouring building. Applicable corrections are given in NZS 6801 and NZS 6803
• Sound level meter/analyser should be self supported (i.e. on a tripod) and not hand-held
• If there is a choice of several neighbouring buildings at a similar distance from the works, the position least affected by other noise sources (such as traffic) should be used
• Take photographs of measurement position and construction activity during measurements
• Record locations of any reflecting surfaces near the measurement position
• Detail all of the above on the survey sheets

There are generally two methods of conducting measurements:

1. Take several fifteen minute samples of representative construction activity
2. Take short (approximately 5 to 30 second) measurements of specific construction events

The first approach is preferable as it allows a direct comparison with construction noise limits. However, contamination by fluctuating residual sound (such as sporadic road traffic) often means that the second approach is required. In this instance it is then necessary to conduct detailed analysis after the survey to calculate the effective construction noise level over a representative period (fifteen minutes to one hour). Procedures for this are provided in NZS 6801 and NZS 6802. Even using the first approach of taking fifteen minute samples, it may often be necessary to take a separate measurement of the residual sound and subtract.

Reporting:

• On site, fill in all parts of the survey sheets
• Record all results on the Construction Noise Management tool
• If required, prepare a formal report for the project team and/or consenting authority

Training

All personnel involved in construction noise management are required to have appropriate training. For staff undertaking construction noise surveys this training should include the following:

• basic acoustic concepts and units
• construction noise sources
• factors affecting sound propagation
• mitigation options
• survey procedures
• equipment operation
• equipment calibration
• meteorological constraints
• residual sound constraints
• data analysis/interpretation

These topics will be covereing in NZTA Environmental eLearning training package. For other acoustics topics and training requirements, refer to the New Zealand Acoustical Society.