Noise Measurement Procedure

The BS 4142:2014+A1:2019 Technical Note was published by the Association of Noise Consultants (ANC) Good Practice Working Group. BS 4142:2014+A1:2019 is the latest iteration of a standard which was first published in 1967, designed to consider the effects of industrial sound with appropriate consideration to the character of that sound as well as its level.

Measurement procedure foreword in the BS 4142:2014+A1:2019 Technical Note is;

“The measurement procedure should be planned prior to leaving for site and be appropriate for the scale of assessment to be undertaken.

Clause 4 of BS 4142 covers good practice in preparation before leaving for site and reference should be made to that and Section 4 of this document when planning the survey and measurements, including:

• Number of positions and type of equipment;
• Survey duration;
• MET (meteorological) data source;
• Local Authority Liaison;
• Location of NSRs (noise-sensitive receptors) and other noise generating plant;
• Potential sources of error and uncertainty;
• Ensuring the subject plant is operating if necessary and can be turned and on off if required; and
• Risk Assessments.

During the survey, the underlying purpose of the measurements should be kept in mind, e.g. to quantify the specific sound level of the equipment, if it is in place, by measuring the ambient and residual sound levels; and to obtain as realistic a measurement as possible of the background sound level at the potentially affected NSRs.

Where the planning of the measurements has taken into account potential sources of error and uncertainty so that these can be minimised, then the appropriate measures should be taken on site to control these. However, the planning stage of the assessment process can only take into account reasonably foreseeable events and the surveyor should still be aware of the potential for variance or unexpected events/conditions and react accordingly.

The consideration of uncertainty should be a continuous process from beginning to end of the assessment and this process must be fully documented in the final report.

Consider whilst carrying out the survey how the survey report will be written, make explicit notes of all sound sources apparent on site including photos if possible and video clips if appropriate. Similarly, describe and assess all relevant NSRs and consider the sound transmission paths to each significant one.

In the case of service yard or vehicular activity, it may be necessary to arrange for demonstration examples of typical activities to be made and a time log of normal operation be provided so that the specific sound level can be calculated.

When arriving at site, consider the risk assessment and determine if there are additional hazards that should be considered. In all cases, the surveyor should put their safety and the safety of others first.”