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.