3M eg4 user manual Glossary of Terms, Background Noise, effects

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APPENDIX

58

Appendix B

Glossary of Terms

B

Glossary of Terms

Background Noise, effects of

Background noise can cause considerable error in measurement when its level is high relative to the level of a noise source of interest. If you can make measurements both with and without the contribution of a noise source of interest, you can mathematically subtract the background noise from the combined measurement, yielding the level of the noise source of interest alone. The accuracy of this determination improves as the difference between the two measurements increases.

To remove background noise

1.Obtain a measurement that includes the contribution of the noise source of interest (the combined measurement).

2.Make a second measurement under exactly the same conditions as in Step 1 but without the presence of the noise source of interest (the background noise measurement).

3.Determine the decibel difference between these two measurements.

4.Find that difference on the x-axis of the figure below.

5.Find the point on the curve directly above this difference.

6.Read the corresponding value on the y-axis for that point (the correction value).

7.Subtract the correction value from the combined measurement.

Example: Measurements with and without the noise source of interest are 91 dB and 90 dB, respectively. For a difference of 1 dB, the background noise correction value is 7 dB. Therefore the level for the noise source of interest without the noisy background is 84 dB.

053-644, Rev H

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eg4

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Contents Edge 3M The Edge Personal Noise DosimeterTable of Contents Setting-up the Edge via DMS Time history……………………………………………………………………………………………………Stopping a study Viewing measurements on the displayTechnical Support Replacing microphone and windscreenPhysical attributes of EdgeDock1 and EdgeDock5 INDEX…………………………………………………………………………………List of Figures List of TablesDosimetry Edge and dosimetryNoise dosimeter Illustration of how the dosimeter operates and processesRange of sound What do the standards say?Applications of the Edge Setting-up your dosimeter parameters for your noise studies Noise assessment stepsRunning your studies View your results via DMSParameter setup screen for eg4 Edge ModelChecking the equipment Identifying your equipmentLED indicator Turning onLED indicators explained Turning offDiagram Display and keypadDocking station functionality 3MTMDetection Mangement Software DMSLoading EdgeDock1 or EdgeDock5 Docking station componentsEdgeDock1 and EdgeDock5 components Powering EdgeDock1 or EdgeDock5  Powering EdgeDock1 or EdgeDock5 How to charge Charging your dosimeterMounting the docking station to a wall Storing the dosimeterUnderstanding what data is stored Noise studiesSummary data Time historyViews on the Edge LoggingViews on Explanation Definitions of data log values and viewsDosimeter views and definitions Weighting Views on Explanation EdgeDose Response LevelDescriptors Variants Lmax variants Dosimeter measurement descriptors/variantsDocking Communicating & downloading dataCustomizing set-up parameters in DMS New Hardware wizard for Edge DockDosimeter setting Dosimeter screenEdge dosimeter settings Dosimeter fields explained for the EdgeDisplay setting Edge display screenSecurity setting Edge security settingAuto Run setting Edge auto run screenFirmware update 10 Edge firmware update screenSaving and sending/setting configurations 11 Saving and sending Edge setupsOverview of running a study Quick Help List typical dosimetry session How to attach the dosimeter Windscreen and maintenancePositioning the Edge on your shirt Checking battery power  Checking battery powerCalibrating  Calibrating the dosimeterResetting the dosimeter  Reset Contrast Setting contrast on dosimeterOn/off/enter button Running studies  How to run a noise studyStarting a run Indicators/Icons on the display  How to stop a noise studyIndicator Icon Explanation Indicators i.e., run, stop, battery, and OLLocking or securing your dosimeter during run Viewing measurements on the display Viewing measurements  How to lock or secure  How to unlockLocking or Securing UnlockingDownloading data  DownloadingDMS start screen Viewing data and data finder  Selecting and viewing dataReport View Example of Edge Report in DMSPanel Layout Viewcharts/graphs Panel layout view viewing the data in charts and graphsLED indicator disable/enable Technical SupportAttaching/Detaching Replacing microphone and windscreen Attaching/Detaching the windscreen and microphone Hard Hat Attachment Kit Hard Hat Attachment kitMechanical characteristics StandardsEnvironmental effects Electrical characteristicsUser Interface EdgeDock1 and EdgeDock5 Physical attributes of EdgeDock1 and EdgeDock5Types MeasurementsMeasurement parameters Communications Special functionsSecurity Auto-RunEdge Block Diagram Edge Block Diagram Appendix B 3M Service WarrantyService Department and Technical Support 1 800 Contacting 3MGlossary of Terms Background Noise, effectsCrest Factor Combining Noise sourcesCriterion Level CL Criterion Time Decibel dBDose Exchange Rate ER also known as the Doubling RateFree field setting microphone Hearing Conservation HC Hertz HzLavg Average Level Lep,dLeq Equivalent Level LoggingMaximum Level Lmax Measurement RangePEL Permissible Exposure Level Projected TimeRandom incidence microphone Response TimeTWA Time Weighted Average ThresholdUpper Limit UL Weighting A, C, Z, etcWindscreen Measurement equations Index Running studies About 3M Personal Safety About Us
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