Divide the cleanroom entrance plane into equal grids not exceeding 430 square feet (40 m2).
Support the SLM approximately 5 feet (1.5 m) above the floor, and at lease 3 feet (0.9m) from walls.
Measure and record the sound pressure levels for each octave band frequency from 63 to 8000 Hertz in the center of each grid.
Follow the above steps for each specified area.
Determine the maximum sound pressure level reading for each octave band center frequency (63 to 8000 Hertz).
Depending on the specification requirements, plot the maximum reading on either a Room Criterion (RC) Curve graph or a Noise Criterion (NC) Curve graph. The RC curve data os preferred for HVAC system noise.
Report and compare the calculated RC or NC curve value with that specified for the spaces or areas.
The permissible RC or NC curve values shall be as specified by the cleanroom owner.
A sound level meter (SLM) with a vibration integrator system and a vibration calibrator.
A signal conditioner with an accelerometer or seismic transducer.
A narrow band, 400-line (or greater) FFT spectrum analyzer with linear and max-hold rms detection.
Take vibration measurements on equipment support pedestals and on the structure floor close to vibration sensitive process equipment.
In general, make vibration measurements in each of three axes (vertical plus two horizontal) at each location.
Determine the average of the data at each location over at least 50 spectra and over a period of at least 1 minute.
The data report should typically included a diagram showing measurement locations.
Plots showing vibration spectra at each location, with vibration amplitudes displayed on a logarithmic scale, and frequency displayed on a linear scale.
A report describing the conditions at the time of the measurements and details of the measuring system including the measurement bandwidth with the predominant vibration frequencies identified.
Acceptance vibration limits shall be specified by the cleanroom owner.