BLOCK 1-DATA ITEM NO.: A040
BLOCK 2-DATA ITEM TITLE: AIRBORNE NOISE TEST REPORTS
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BLOCK 3-DATA DESCRIPTION:
- Airborne Noise Test Reports shall document compliance for individual units of machinery and equipment and HVAC systems to support the requirements identified in the Noise Control Plan. Each report shall contain the following information:
- Test and equipment information.
- Equipment being evaluated, including contract number.
- Ship names and hull number, if known, for which the unit is being acquired.
- Evaluation measurements being performed.
- Evaluating activity and test site.
- Test date.
- Data analysis date.
- Equipment specification acceptance criteria.
- Driven and driver unit manufacturers and serial numbers.
- Driver unit power.
- Rated electrical characteristics, including volts, amps, and phase.
- Rated fluid media parameters (flow rates, temperatures, pressures, etc.).
- Equipment rated operational speeds (driver and driven unit revolutions per minute (r/min), etc.).
- Equipment noise and vibration sources and their frequencies of excitation (rotationals, gear tooth contact, blade rate, etc.).
- Resilient mount manufacturer and model number.
- Dates of resilient mounts used.
- Number of resilient mounts used.
- If non-Navy standard resilient mounts are used, provide mount characteristics including load rating and resonant frequency data.
- Equipment load during test (full, half, etc.).
- Operating speeds during test.
- Throttling conditions, if any.
- Operating suction and discharge fluid media parameters during test (flow rates, pressures, and temperatures, etc.).
- Electrical inputs, outputs, or both during test.
- Block diagrams and identification or make, model, and serial numbers of system calibration instrumentation used.
- Block diagrams and identification of make, model, and serial numbers of system calibration instrumentation used.
- Place and data of latest laboratory calibration of measurement instruments, system calibration instruments (including field calibrators), and analysis instruments.
- Drawings and Sketches to Show Assembly Information, Equipment Details and the Test Set Up:
- Overall unit dimensions and orientation (vertical, horizontal, etc.) during test.
- Identification of major components.
- Interface information.
- Mounting locations and dimensions.
- Weights and center of gravity of major components.
- Resilient mount orientation (vertical, horizontal, angle), approximate load on each mount, attachment locations, overall unit weight and center of gravity.
- Pedestal or subbase dimensions, materials and weight, when applicable.
- Dimensions, materials and weight of the mounting fixture if a mounting fixture other than the standard fixture is used.
- Arrangement and description of flexible pipes and ducts, if used.
- Arrangement of electrical power leads.
- Location and description of test instrumentation used to measure r/min, flow rates, total discharge head, etc.
- Locations of resilient mounts and pedestals or fixtures that support the equipment.
- Locations and orientation of each microphone relative to equipment features.
- Locations of equipment air inlet and discharge openings.
- Description of acoustical center of sound source, assumed or measured.
- Acoustical environment (indoor).
- Description of location and orientation of test unit relative to floor, walls, ceiling and contents of test room.
- Description of test location (anechoic, reverberant, etc.), dimensions of the test room or chamber description of the physical treatment on walls, ceiling and floor.
- Acoustical environment (outdoor). Description of location and orientation of test unit relative to buildings, structures or other reflecting surfaces or objects.
- Description of the ground surface, and wind direction and speed.
- Test data shall be included in the reports and shall include:
- Tabular or graphic records of the A weighted levels, C weighted levels, octave band levels, and peak A-weighted sound levels required to be measured, including background noise. Both corrected and uncorrected data, along with all correction factors, etc., needed to obtain absolute levels to compare to specification limits.
- Tabulation of measured levels exceeding specifications and the corresponding specification level.
- The Airborne Noise Test Report shall include the following:
- Reference quantity identification. The applicable reference quantity shall be indicated on every table, figure, and graph, and at least once in the text. The reference quantity may be introduced by “re:” which indicates that the level is “with reference to.” For example, the 125 Hz octave band level re: 20 mPa is 85 dB.
- Measurement bands. The bandwidths of the measurement basis shall be reported together with the measured levels. Normal procedure for reporting measured levels shall include the bandwidth and the band center frequency with the level. For example, the one-third octave 100 Hz band level was 85 dB re: 20 m Pa, the 10 Hz bandwidth 100 Hz band level was 85 dB re: 20 m Pa , or the 6 percent bandwidth 100 Hz band level was 85 dB re: 20 m Pa.
- Plotting Format. Plotting formats of data in which a level in dB on a linear scale is plotted against frequency on a logarithmic scale shall be made on graphs in which a factor of ten in frequency is equal in length to 25 dB (preferred) or 50 dB. Where the bandwidth of analysis is one-third octave or larger, one factor of ten in frequency shall be 50mm. The ordinate and abscissa of all graphs shall be labeled so that levels and frequencies can be readily understood without need to refer elsewhere in the report.
BLOCK 4-REVIEW REQ.:
Allow 30 days for Government review and comment.
BLOCK 5-SUBMITTAL SCHEDULE:
NLT 20 DATC and 20 days after retest for each unit that fails to meet airborne noise requirements.
Reference: DRL A040 21 July 2000