Now you can start measuring. The unit is placed in an open space on an asphalted reflecting surface (indicated by a cross). Make sure nothing is placed around the unit within 24m. Then, we measure 6 points around the unit. The measuring positions are fixed to the ground at 8m from the unit. 4 of those points are at a height of 1.5m and at a distance of 8m from the center of the unit. These points are distributed evenly within the 8m. The 2 other measuring points are at a height of 5.68m and at a distance of 8m from the center of the unit as well. These measuring points are numbered in order to simplify the administration of the form. We are measuring the average value for L

_{WA}.

The sound level meter has to be calibrated with a maximum deviation of 0.3dB(A). The meter has to be inclined in a way that the microphone points to the center of the generating set. Each measurement lasts at least 15 seconds. The values have a max. deviation of 1dB. If the values exceed this max. deviation, you will have to measure again and again until there are at least 3 measured values between a margin of 1dB. Normally, measurements are conducted with a load of 75%. This measurement has to be rectified. We also recommend you to conduct measurements on several generating sets of the same type, since there is a correction on this as well. The more units you will test, the smaller the correction. Eventually, the sound level has to comply with the 2000/14/EC regulation and the measurement has to be executed according to the ISO 3744 regulation.