The sound level meter shall be operated in accordance with the instrument manufacturer’s instructions and as follows:
    (1) Microphone Orientation. The microphone shall be oriented in relation to the source of the sound in accordance with instrument manufacturer’s instructions. Where the instruction manual is vague or does not include adequate information, a specific recommendation shall be obtained from the manufacturer.
    (2) Meter Setting. The meter shall be set for the A-weighted network and fast response.
    (3) Calibration Check. An external calibration check shall be made before and after each period of use and at intervals not exceeding 2 hours when the instrument is used longer than a 2 hour period.
    (4) Meter Reading. The recorded reading shall be the highest sound level obtained as the vehicle passes by, disregarding unrelated peaks due to extraneous ambient noises.
    (5) Ambient Sound. Measurements shall be made only when the A-weighted ambient sound level, including wind effects and all sources other than the vehicle being measured, is at least 10 dB lower than the sound level of the vehicle.
Rulemaking Authority 403.061 FS. Law Implemented 403.061, 403.415(9), 316.293(3) FS. History-New 11-27-74, Formerly 17-18.06, 17-18.060.