USER GUIDE Noise Dosimeter with PC Interface Model 407355
Introduction Congratulations on your purchase of the Extech 407355 Personal Noise Dosimeter. The 407355 is designed to test noise exposure in accordance with OSHA, MSHA, DOD, ACGIH, and ISO standards. Fast and easy on-site surveys help determine noise reduction requirements. The meter can also be used in SLM (sound level meter) mode where sound pressure levels are monitored from 70 to 140dB.
Descriptions Display Description 1. FAST Response Time mode 2. SLOW Response Time mode 3. Noise Exposure test active 4. Memory mode alert 5. Noise Exposure test paused 6. Unit of measure for Noise Exposure test 7. Battery Status Indicator 8. Event memory banks (E1-E5) 9. 115dB limit (headphone) indicator 10. Numerical display digits 11. Unit of measure for sound level readings 12. 140dB PEAK indicator 13. Elapsed time mode for noise exposure tests 3 407355-en-GB_v3.
Meter Description 1. Microphone (lapel clip not shown) 2. Microphone cable 3. Microphone connector 4. LCD display 5. Push-buttons: ON-OFF Press to turn the meter ON; Press and hold to turn the meter OFF. RESET This button has a variety of uses including clearing stored data and accessing the Programming mode as described in the manual. RUN Press to begin a noise survey test in Dosimeter mode or datalogging in SLM mode.
Operation Getting Started 1. Power the instrument by pressing the green button. 2. When the unit is turned on, all display items switch on briefly followed by ‘dOSE’, the Criterion Level (Lc), Threshold Level (Lt), and Exchange Rate (ER) respectively. These parameters are defined in the Noise Exposure related sections of this manual. 3. If the meter does not switch on when the power button is pressed, check that the batteries are installed and are fresh.
9. Use the MODE button at any time to view the elapsed time of the test. Press the MODE button until the TIME display icon appears. Now the elapsed time will appear in hours and minutes. Press the RUN button again to return to the %DOSE display. 10. To end the noise survey and SAVE your recording Press and hold the RUN key for >3 seconds. The Clock icon will disappear and the Event bank will start flashing. Read the accumulated noise exposure value on the LCD.
Calibration Procedure Note that an acoustical calibrator (such as the Extech 407744 or 407766) is required to calibrate the 407355. Extech Instruments can also calibrate the instrument and provide an N.I.S.T. certificate if desired. 1. Set the instrument to the Sound Level Measurement Mode (dBA) using the MODE button. 2. Set the response time to SLOW (see the Programming section) 3. Insert the 407355 microphone into the microphone cavity of the calibrator. 4. Turn the calibrator ON for 94.
Dosimetry Parameter Descriptions % DOSE The unit of measure, % DOSE, is used to quantify noise exposure measured during a work shift. 100% dose is the maximum allowable noise exposure in accordance with OSHA, MSHA, DOD, ACGIH, and ISO standards. Most standards specify Criterion Level, Exchange Rate, Response Time, and Frequency weighting for the dosimeter as discussed next. EVENT SELECT Press the EVENT button to enter the EVENT mode.
PC Interface This meter has the capability to connect to and communicate with a PC. To install and use the software, please refer to the instructions provided on the supplied CD-ROM and/or the instructions provided in the HELP Utility within the software program. Check the software download page of the website www.extech.com for the latest version of the PC software and its operating system compatibility. Battery Replacement and Status Display The 407355 is powered by four (4) ‘AAA’ 1.
Specifications Display Multi-function LCD Units of measure dBA (‘A’ weighted decibels) for sound level % DOSE for accumulated noise exposure Measurement ranges 70 to 140dBA for sound level (SPL) measurements 0.01 to 9999 %DOSE for noise exposure surveys Standards applied ANSI S1.
Conversion Charts OSHA Permissible Noise Exposures Duration per day, hours Sound level dBA, slow response 8 90 6 92 4 95 3 97 2 100 1.5 102 1 105 0.5 110 0.25 or less 115 Source:29 CFR 1910 Table G-16 Conversion from Percent Noise Exposure or Dose to 8-Hour Time Weighted Average Sound Level(TWA) Dose or percent TWA (dBA) 50 85.0 55 85.7 60 86.3 65 86.9 70 87.4 75 87.9 80 88.4 85 88.8 90 89.2 95 89.6 100 90.0 105 90.4 110 90.7 115 91.1 120 91.3 125 91.
