Noise measurements in Risavika
The companies in Risavika in cooperation with the municipality of Sola have joined forces to measure noise emissions. A system for continuous monitoring of sound levels is established. The system under the name of Desibel is administered by the Stavanger region Havnedrift AS and has a broadly composed board consisting of representatives of the industry in Risavika and an observer from Sola municipality.
Five measuring stations have been placed in strategic places, this in cooperation with Risavika actors and a consulting company in the field of noise. The results so far show that noise levels in most cases are below the current limit values, although in some cases there may have been exceedances of the maximum noise level. Experienced, we still see that much of the noise that is detected comes from birds, car traffic, aircraft noise and bad weather like rain and strong winds. Until May 2014, the sound recordings first entered when the noise reached a predetermined peak, but in May 2014, it was decided that the system would perform continuous recording, as it would be preferable to record in quieter periods than has been the case until now.
We present data including background noise on the web. The results show the “natural” variations in the sound level recorded at the various measurement stations, including all background noise. In many cases, background noise predominates.
On this page you will find two maps with the weighted average level of the day (Lden) and the average night level (Lnight). The maps show location of the measurement stations. At each measurement station there is a box indicating the calculated (not actual) noise level for a situation with many noise sources operating in Risavika. Sound contributions from road traffic, aircraft and industrial clothing are also included in the calculation. The noise zones in the map show the sound propagation for this situation. Measured sound level is shown in the same box just above the calculated values. Measured values include all noise that occurs at the measurement point. The measured values show the average sound level for the whole of the last month, as well as the worst day in the last month. To assess whether noise levels may have exceeded, measured values must be compared to calculated. Measured values must therefore not be compared to the limit values. Distance attenuation causes the noise level at the neighbors to be lower than at most measurement stations. If the measured values are higher than those calculated, this may be due to noise from Risavika or “false” contributions. In most cases, what is the cause must be clarified with listening.
In addition to the simple values in the maps, this page also contains the sound levels for each hour in each measurement station. Sound levels appear as curves for the day you choose to watch. Here you will find detailed information about the sound level for 30 days back in time with a 7 day delay. This gives the companies that are connected to the appointment time to analyze the data and take action if necessary.
It is important to note that noise is reduced over the distance. For example, shows the measurement station at Tjora Lden 60, it will be within the T1442 limit of 55db due to the distance to the measurement point. If the distance from the measurement point is doubled from 100 meters to 200 meters, the noise is averaged by 6 db.
The companies that are members of Desibel have internal routines where they monitor the noise measurements on a continuous basis.