DI-HFAC-81975 Noise Measurement Report

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DI-HFAC-81975

d. A physical description of the test environment area, including potential reflecting surfaces, if

appropriate, a sketch of contributing noise sources, normal personnel operating positions,

microphone locations, incorporation of windscreens, orientation angles of the microphones with

reference to the noise source, and the location of personnel present during the test(s). A diagram,

drawn to scale, of the test environment shall be provided if it would aid in understanding the test

area. Transducer locations and orientations for weapons shall be specified in polar coordinates

with the origin being a point below the muzzle with the barrel or tube at 0 degrees elevation.

e. Weather conditions during outdoor measurements (e.g., air temperature, relative humidity,

wind direction and speed, barometric pressure, cloud cover, incorporation of windscreens, and

other relevant atmospheric conditions).

f. Measurement instrumentation (e.g., system description of instrumentation used for the

measurements, name, model, serial number, control settings, manufacturer, system gain, date of

calibration, and period of calibration).

g. A description of the operational conditions under which the test was conducted (e.g., speed,

revolutions per minute, load, transducer locations and orientation, weapon height, and weapon

elevation), including the identification of subsystems and auxiliary equipment operating

concurrently.

h. For ground equipment systems under test, the identification of the equipment whose noise is

being measured, nomenclature, type, serial number, mileage (if appropriate), and any

modifications to the equipment. For ground vehicles, include speed, gear, load configurations,

duty cycle, and description of the test surface. If commercial test standards were used that do not

include load, the report shall specifically stipulate the loading conditions used.

i. The date, time of day, location of the test(s), and ambient noise level using the same

bandwidth employed for the measurements of the noise source(s).

j. The name, address, telephone number, and e-mail address of personnel making the noise

measurements, and of personnel such as official witnesses and equipment operator(s).

k. Raw data files plus any correction factors applied. Pressure histories in a digitized form.

The digitizing rate and calibration data necessary to accurately reproduce the waveform shall

also be provided.

l. Measurement data (e.g., unweighted sound pressure level, A-weighted sound pressure level,

C-weighted sound pressure level, peak sound pressure level, full octave sound pressure level,

one-third octave sound pressure level) at each operator or crew position(s), representative

passenger position(s), and occasionally occupied position(s).

3.2. Steady-state noise of personnel-occupied areas. In addition to the applicable general data

in 3.1 above, the NMR shall contain the following with respect to steady-state noise.

a. The noise limit category selected for communications.

b. Documentation of compliance or non-compliance with the required noise limit.