(a) Audiometers and audiometric testing devices shall meet the current standards of the American National Standards Institute (ANSI) or the International Electrotechnical Commission.(b) Audiometric testing not conducted in a stationary acoustical enclosure.(1) A notation shall be made on the hearing test if testing was not done in a stationary acoustical enclosure. Sound-level measurements must be conducted at the time of the testing to ensure that ambient noise levels meet permissible standards for testing threshold to 20 dB based on the most current ANSI "ear covered" octave band criteria for Permissible Ambient Noise Levels During Audiometric Testing, or the test environment shall have a maximum allowable ambient noise level of 42 dBA.(2) Ambient noise level of the location of the audiometric testing, if not done in a stationary acoustical enclosure, shall include a notation on the hearing test of the following items:(A) type(s) of equipment used to determine ambient noise level;(B) model and serial number of equipment used to determine ambient noise level;(C) date of last calibration of equipment used to determine ambient noise level; and(D) the ambient noise level of the test environment.(c) Audiometric testing conducted in a stationary acoustical enclosure.(1) A notation shall be made on the hearing test if testing was done in a stationary acoustical enclosure.(2) A stationary acoustical enclosure includes, but is not limited to, an audiometric test room.(A) An audiometric test room is any enclosed space in which a listener is located for the purpose of testing hearing. An audiometric test room may also be known as:(i) an audiometric test area;(ii) a hearing test space; or(iii) a hearing test room.(B) An example of an audiometric test room would be a prefabricated room known as:(i) an audiometric test booth;(ii) a suite; or(iii) a sound treated room.