Noise and Vibration Report - Transnet

ENVIRO-ACOUSTIC RESEARCHSCOPING NOISE REPORT – TRANSNET: SWAZI RAIL LINK – DAVEL YARD TO NERSTON RSA ROUTEimpacts could be objectively assessed, it was necessary to establish a rating system,which was applied consistently to all the criteria. For such purposes each aspect will beassigned a value as defined in the third column in the tables below during theEnvironmental Noise Impact Assessment stage.The impact consequence is determined by the summing the scores of Magnitude (Table6.2), Duration (Table 6.3) and Spatial Extent (Table 6.4). The impact significance isdetermined by multiplying the Consequence result with the Probability score (Table 6.5).An explanation of the impact assessment criteria is defined in the following tables.Table 6.2: Impact Assessment Criteria - MagnitudeThis defines the impact as experienced by any receptor. In this report the receptor is defined as anyresident in the area, but excludes faunal species.Rating Description ScoreLowLowMediumMediumHighVery HighIncrease in average sound pressure levels between 0 and 3 dB from the ambient soundlevel.No change in ambient sound levels discernible.Total projected noise level is less than the Zone Sound Level in wind-still conditions.Increase in average sound pressure levels between 3 and 5 dB from the ambient soundlevel.The change is barely discernible, but the noise source might become audible.Increase in average sound pressure levels between 5 and 7 dB from the (expected)ambient sound level.Sporadic complaints expected.Any point where the zone sound levels are exceeded during wind still conditions.Increase in average sound pressure levels between 7 and 10 dB from the ambientsound level.Medium to widespread complaints expected.Increase in average sound pressure levels higher than 10 dBA from the ambient soundlevel. Change of 10 dBA is perceived as ‘twice as loud’, leading to widespreadcomplaints and even threats of community or group action.Any point where noise levels exceed 65 dBA at any receptor.246810Table 6.3: Impact Assessment Criteria - DurationThe lifetime of the impact that is measured in relation to the lifetime of the proposed development(construction, operational and closure phases). Will the receptors be subjected to increased noiselevels for the lifetime duration of the project, or only infrequently.Rating Description ScoreTemporary Impacts are predicted to be of short duration (portion of construction period) and 1intermittent/occasional.Short term Impacts that are predicted to last only for the duration of the construction period. 2Long termPermanentImpacts that will continue for the life of the Project, but ceases when the Projectstops operating.Impacts that cause a permanent change in the affected receptor or resource (e.g.removal or destruction of ecological habitat) that endures substantially beyond theProject lifetime.45P a g e | 36