1.1 This classification covers methods of calculating single-number acoustical ratings for laboratory and field measurements of sound attenuation obtained in one-third octave bands.

1.2 The name given to the single-number rating is assigned by the test method that invokes this classification.

1.3 Test methods that invoke this classification include:

1.3.1 Test Method E 90The single-number rating is called sound transmission class (STC).

1.3.2 Test Method E 336Single-number ratings are field sound transmission class (FSTC), noise isolation class (NIC), and normalized noise isolation class (NNIC).

1.3.3 Test Method E 596The single-number rating is called noise isolation class (NIC).

1.3.4 Test Method E 1414The single-number rating is called ceiling attenuation class (CAC).