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##### Support / Are all LAeq values obtained by converted LA10 values?

« Last post by**roger**on

*July 30, 2021, 02:46:24 PM*»

No, the noise index that is calculated depends on the calculation method that you use.

NoiseMap has three different types of noise source, namely Roads, Railways and Open Site sources. Each type of source is calculated by its own calculation method as follows.

For ordinary roads, NoiseMap uses 'Calculation of Road Traffic Noise' (CRTN), which calculates levels in terms of the index LA10, so if you need LAeq values when using CRTN, you do have to convert the index. NoiseMap has a built-in conversion method that you can use.

For noise from Open Sites, NoiseMap uses the BS5228/ISO9613 methodologies, which calculate levels in terms of the LAeq index. These methodologies consider 'Haul Routes', which are like roads, but you have to set up noise source details for the vehicles and machines using the Route; and fixed sources which are stationary at a given point.

For Railway Noise, the sources are Rail Tracks and the calculations are made either in terms of the LAeq index or the LAmax index.

A noise model can contain any or all of these sources. However, when you run a calculation, you first choose the calculation method, which then only evaluates the sources relevant to the chosen method. If you have additional types of sources, you have to run additional calculations using the relevant calculation method.

When you have calculated for the required noise sources, you can use the Results Processor to compare or combine the various source levels.

NoiseMap has three different types of noise source, namely Roads, Railways and Open Site sources. Each type of source is calculated by its own calculation method as follows.

For ordinary roads, NoiseMap uses 'Calculation of Road Traffic Noise' (CRTN), which calculates levels in terms of the index LA10, so if you need LAeq values when using CRTN, you do have to convert the index. NoiseMap has a built-in conversion method that you can use.

For noise from Open Sites, NoiseMap uses the BS5228/ISO9613 methodologies, which calculate levels in terms of the LAeq index. These methodologies consider 'Haul Routes', which are like roads, but you have to set up noise source details for the vehicles and machines using the Route; and fixed sources which are stationary at a given point.

For Railway Noise, the sources are Rail Tracks and the calculations are made either in terms of the LAeq index or the LAmax index.

A noise model can contain any or all of these sources. However, when you run a calculation, you first choose the calculation method, which then only evaluates the sources relevant to the chosen method. If you have additional types of sources, you have to run additional calculations using the relevant calculation method.

When you have calculated for the required noise sources, you can use the Results Processor to compare or combine the various source levels.