7030.0070 SOUND ATTENUATION MEASUREMENT METHODOLOGY.
Sound level measurements made for assessing sound attenuation as specified in part 7030.0050, subpart 3, item B, C, or D, shall be made according to the requirements of this part.
The equipment shall meet the requirements specified in part 7030.0060, subpart 2.
The equipment must meet the calibration requirements specified in part 7030.0060, subpart 3.
The measurement procedure described in FHWA-DP-45-1R, section 8 must be used for determination of the sound attenuation.
Methods equivalent to those described in subpart 4 may be used provided they are approved by the commissioner of the Minnesota Pollution Control Agency. The commissioner shall approve an alternative method if the commissioner finds that the method will produce representative data and results which are as reliable as the methods specified in subpart 4.