4Q1.7-303.pdf

Manual: 4Q1.7 Procedure: 303 Revision: 10

OPERATION OF SOUND LEVEL METER Effective Date: 05/08/2018 Type-Class: Tech-Ref Page: 1 of 6

1.0 INTRODUCTION

1.1 Purpose

Provide instructions for operating the Brüel and Kjaer (B&K) Sound Level Meter, Type 2232.

1.2 Scope

The guidelines in this procedure are used by Respiratory Equipment Facility (REF) personnel for operation of the sound level meter to determine noise levels in air-supplied plastic suits and hoods for regulatory compliance. The Sound Level Meter (SLM) response is checked daily prior to beginning of the workday (pre-calibration) and at the end of workday (post-calibration).

The following form may be utilized in the performance of this procedure:

ISF-REF-004, REF Sound Level Meter Response Check

2.0 GENERAL INFORMATION

2.1 Definitions and Abbreviations

dB(A) – A-sound pressure level adjusted to represent a response nearly equal to that of the human ear.

dB – Used to measure sound level.

2.2 Responsibilities

1. REF Personnel are responsible for operating sound level meter to determine the noise level in plastic suits and hoods.

2. The REF Lead is responsible for providing technical support for use of the Sound Level Meter (SLM).

3. Industrial Hygiene (IH) Calibrations is responsible for maintaining, calibrating, and performance testing of the Sound Level Meter and Sound Level Meter Calibrator.

Operation of Sound Level Meter Revision: 10 Page: 2 of 6

2.3 Information

1. The Brüel and Kjaer Type 2232 Sound Level Meter is a portable, battery-operated, precision sound level meter. The type 2232 unit weighs 1 pound and is powered by two 9V batteries that provide about 30 hours of operation.

The instrument is capable of measuring sound levels from 34 dB(A) to 130 dB(A) on two ranges. The instrument is field-calibrated with a B&K Sound Level Calibrator, Type 4231, which generates a sound pressure level of 94 dB(A) (± 0.2 dB). The meter display shows overload, under-range, and low battery functions when these conditions occur.

2. Sound level meter calibration shall be confirmed each time the meter is turned off and then back on throughout the day.

3.0 PRECAUTIONS AND LIMITATIONS

3.1 Safety

1. A hazard analysis has been performed on this task (INF-37229).

3.2 Acceptance Criteria

The sound level meter should maintain its actual response check reading of 93.8 dB(A), within ± 0.5 dB(A) during verification.

4.0 PREREQUISITES

4.1 Field Preparation

1. VISUALLY INSPECT the sound level meter and sound level calibrator calibration stickers to verify that the instruments are within their calibration time period.

2. RECORD the date and the sound level meter and calibrator Commodity Management Center (CMC) number on ISF-REF-004 form.

3. IF the calibration time period has expired, THEN

SEGREGATE the instrument.

4. TAG it with a completed OSR 4-23, Instrument Repair and Calibration.

5. RETURN it to IH Calibrations.

Operation of Sound Level Meter Revision: 10 Page: 3 of 6

5.0 PERFORMANCE

5.1 Pre-Calibration

1. IF fitted with random incidence corrector, THEN

REMOVE random incidence corrector from microphone.

2. SET controls on the meter as follows:

range selector: 70 to 130 dB(A) detector response: FAST reset: AUTO power: OFF

3. OBTAIN a sound level calibrator.

4. GENTLY PLACE sound level calibrator over microphone, AND

TURN calibrator on.

5. SWITCH the sound level meter power switch to ON.

NOTE

The sound level calibrator shuts off automatically after 50 seconds.

6. VERIFY reading on sound level meter display.

7. IF reading is 93.8 dB(A), THEN

PROCEED to Step 5.1.10.

8. IF reading is NOT 93.8 dB(A), THEN

LOCATE the sensitivity adjustment directly below microphone.

9. ADJUST the sensitivity adjustment trimmer, using a small screwdriver, to obtain a reading of 93.8 dB(A) on the meter display. This is done while the sound level calibrator is ON and audible.

10. GENTLY REMOVE the calibrator.

11. RECORD the reading on ISF-REF-004 in the pre-calibration meter display column, AND

SIGN the signature block.

Operation of Sound Level Meter Revision: 10 Page: 4 of 6

5.2 Sound Level Meter Operation

1. SET range selector to the 34 to 94 dB(A) range.

2. SET the detector response switch to SLOW.

3. ENSURE the reset switch is on AUTO.

4. ENSURE the instrument power switch is still on.

5. GENTLY PLACE sound level calibrator over microphone, AND

TURN calibrator ON.

6. READ noise (sound) level on meter display.

NOTE

The sound level meter should read within ± 0.5 dB(A) during the verification.

7. VERIFY the sound level meter has maintained its actual response check reading of 93.8 dB(A).

8. IF the sound level meter has NOT maintained its actual response check reading [± 0.5 dB(A)], THEN

A. RECALIBRATE the sound level meter per Step 5.1.2.

B. CONTACT the REF Lead.

9. GENTLY REMOVE the calibrator.

5.3 Post-Calibration

1. LEAVE the sound level meter turned ON.

2. SET controls on the meter as follows:

range selector: 70 to 130 dB(A) detector response: FAST reset: AUTO power: OFF

3. OBTAIN the calibrated sound level calibrator.

4. PLACE sound level calibrator over microphone, AND

TURN calibrator on.

Operation of Sound Level Meter Revision: 10 Page: 5 of 6

5.3 Post-Calibration, (cont.)

5. SWITCH the meter power switch to ON, AND

OBSERVE reading.

6. GENTLY REMOVE the calibrator.

NOTE

Reading on meter display should be 93.8 dB(A). The sound level meter should read within ± 0.5 dB(A) during the post calibration.

7. RECORD the reading on ISF-REF-004 in the post-calibration meter display column, AND

SIGN the signature block.

8. IF reading is not within range, THEN

CONTACT the REF Lead.

9. RECORD any comments or observations in the Comment column on

ISF-REF-004.

10. IF originally fitted with random incidence corrector, THEN

A. REINSTALL random incidence corrector.

B. TURN the sound level meter OFF.

6.0 REFERENCES

Hazard Analysis INF-37229

OSR 4-23, Instrument Repair and Calibration

7.0 RECORDS

Records generated as a result of implementing this procedure are maintained in accordance with Manual 1B, Procedure 3.31, Records Management.

ISF-REF-004, REF Sound Level Meter Response Check

8.0 ATTACHMENTS

Appendix 8.1 Diagram of Sound Level Meter Control

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APPENDIX 8.1

Diagram of Sound Level Meter Control

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