Values are what we, as a profession, judge to be right. They are more than words-they are the moral, ethical, and professional attributes of character. . . there are certain core values that must be instilled in members of the U.S. Army-civilian and uniformed soldier alike.
Industrial Hygiene. Noise. Full text of hearing conservation program. Materials on acoustics. Noise attentuation. Noise basics. Technical material from NIOSH. Hearing protection devices. Noise induced hearing loss.
A noise reduction coefficient (NRC) is a single number that represents an average of the sound absorption coefficients in the 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz octave bands. Detail of its calculation can be found in the ASTM C-423 standard.