(a) The audiometric reading below which there is no hearing impairment shall be specified as 25 decibels (ANSI-1969) using the average of the hearing levels at the four-speech frequencies of 500, 1,000, 2,000 and 3,000 Hz. In other words, if the hearing level of an individual in these four frequencies averages 25 decibels or less, no hearing impairment shall be considered.

(b) The point at which the inability to hear should be deemed total shall be specified as 92 decibels re: ANSI-1969, using the average of the hearing levels at the four-speech frequencies of 500, 1,000, 2,000 and 3,000 Hz.