1.1This classification covers methods of calculating single-number acoustical ratings for laboratory and field measurements of sound attenuation obtained in one-third octave bands.
1.2The name given to the single-number rating is assigned by the test method that invokes this classification.
1.3Test methods that invoke this classification include:
1.3.1Test Method E90–The single-number rating is called sound transmission class (STC).
1.3.2Test Method E336–Single number ratings are noise isolation class (NIC), normalized noise isolation class (NNIC), apparent sound transmission class (ASTC), and field sound transmission class (FSTC).
1.3.3Test Method E596–The single-number rating is called noise isolation class (NIC).
1.3.4Test Method E1414–The single-number rating is called ceiling attenuation class (CAC).
1.4The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
