Test Procedure Sound and Vibrations High Power Rigs and Generators
Test Procedure Sound and Vibrations
A. Objective of the measurements The objective is to determine the sound power level of the installation at maximum capacity and vibration levels at the base of the unit. The average surface sound level at a distance of 1 meter has to be determined. This parameter has to be compared to the guaranteed level.
B.1 General The measurements will be carried out with an acoustic intensity sound meter in accordance with the standard ISO 9614-2. The sound meter has a traceable calibration certificate to IEC-61672 and 61260. The vibration analyzer to DIN-45659 and ISO-5349.
B.2 Measurement uncertainty It is expected that it is difficult to measure the exact noise level emitted by the installation itself. This is caused by the expected high noise level that is emitted by other noise sources. The other uncertainties are:
- According to ISO 9614-2, the uncertainty in the sound intensity measurements can vary from 1.5 up to 4 dB.
- The measured noise level in the hall is different from a noise level in open field, the level is affected by the materials and the dimensions of the hall (reflections and absorption).
- The uncertainties for the vibration measurements are 0.01 mm/s, the total uncertainties according to the ISO standards will be around 0.1 mm/s.
C. Measurement Procedure
1 Preparation before the testing day
1.1 AV CONSULTING B.V. makes an appointment with the client for a testing day on which the installation will be tested. This is the purchase test. The client guarantees that the installation will operate at maximum capacity. 1.2 On the day prior to the testing day, AV CONSULTING B.V. contacts the client to ensure that the test will be carried out the next day. 1.3 If the planning of testing days changes the client will contact AV CONSULTING B.V. as soon as possible to make an appointment at a new date. 2 Test day
2.1 The noise measurements will be carried out with an acoustic intensity sound meter in accordance with the standard ISO 9614-2. The sound meter has a traceable calibration certificate. 2.2 The intensity meter is acoustically calibrated on location. 2.3 At first indicative measurements are made to define surfaces that are useful for the definite measurements. 2.4 On the floor of the hall the surfaces to be scanned are marked with tape or crayon and vertically mounted beams. 2.5 The surfaces around the installation are scanned with the sound intensity probe in accordance with ISO 9614-2. All surfaces are scanned twice; the two scanning paths are orthogonal. 2.6 During the measurements the field indicators are checked. If the field indicators are not in compliance with the Standard ISO 9614-2 then a surface at another distance is chosen (in compliance with the standard). 2.7. The vibration measurements will be carried out on the same day as het sound intensity measurements. 2.8. Calibration of the vibration analyzer will be done in the office of AV Consulting B.V. 2.9 The vibration measurements will be done on the base frame and rigid parts of the installation.
The sound power level is calculated according to chapter 9 of ISO 9614-2. This calculation is carried out for the complete installation. The average surface noise level at a distance of 1 meter is compared to the guaranteed level. The vibration levels will be analyzed according to ISO-2631 “Whole body combined” and ISO-5349 “Hand/arm measurements”. Also vibration measurements can be conducted on the installation and analyzed according to ISO 10816: “Mechanical vibration — Evaluation of machine vibration by measurements on non-rotating parts”.
E. Introduction of measurement uncertainties
The measured and calculated sound and vibration level is evaluated. If the level is strongly influenced by other installations or sources, a correction has to be made. An expert judgment is made to correct the calculated value. F. Report The Norsoc data-sheets are written in English. In the sheets the relevant issues are described. These issues are:
- Dimensions of the installation
- Measurement environment
- Measurement procedures
- Acoustical data, sound intensity (power) levels in frequency bands
- Vibration data such as velocity, acceleration and displacement levels will be presented as a root mean square value and in small frequency bands through fast fourier transform analysis.
AV Consulting B.V. can also assist the client in the engineering of the installation to meet the noise and vibration demands as specified in the NORSOC S002.
More information about sound measurements (dutch)
More information about vibrations at working location