Noise and Vibration Report - Transnet

ENVIRO-ACOUSTIC RESEARCHSCOPING NOISE REPORT – TRANSNET: SWAZI RAIL LINK – DAVEL YARD TO NERSTON RSA ROUTE3 EXISTING ENVIRONMENTAL SOUND CHARACTER3.1 MEASUREMENT PROCEDUREAmbient (background) noise levels will be measured in accordance with the South AfricanNational Standard SANS 10103:2003 "The measurement and rating of environmental noisewith respect to land use, health, annoyance and to speech communication". The standardspecifies the acceptable techniques for sound measurements including:• type of equipment;• minimum duration of measurement;• microphone positions;• calibration procedures and instrument checks; and• weather conditions.Where existing railway noise is to be measured the methodology as defined by “ISO 3095,Acoustics – Measurement of noise emitted by railbound vehicles” will be used.3.2 LIMITATIONS: ACOUSTICAL MEASUREMENTS AND ASSESSMENTSLimitations due to environmental acoustical measurements include the following:• Ambient sound levels are the cumulative effects of innumerable sounds generated atvarious instances both far and near. High measurements may not necessarily meanthat noise levels in the area are high. Similarly, a low sound level measurement will notnecessarily mean that the area is always quiet, as sound levels will vary over seasons,time of the day, faunal characteristics, vegetation in the area and meteorologicalconditions (especially wind). This is excluding the potential effect of sounds fromanthropogenic origin. It is impossible to quantify and identify the numerous sourcesthat influenced one 10-minute measurement using the reading result at the end of themeasurement;• Defining ambient sound levels using the result of one 10-minute measurement will bevery inaccurate (very low confidence level in the results) for the reasons mentionedabove. The more measurements that can be collected at a location the higher theconfidence levels in the ambient sound level determined (at that location). The morecomplex the sound environment, the longer the required measurement (especiallywhen at a community or house);• Determination of existing road traffic and other noise sources of significance areimportant (traffic counts etc);P a g e | 17