Measurements shall be taken at the following locations:
The microphone shall be at least three feet (3 ft.) above the surface while measurements are being taken, except for motor vehicle stationary tests which shall be determined.
The microphone orientation shall be as specified by the manufacturer.
Measurements conducted on private property shall be taken with the permission of the owner or the owner's representative, or under the authority of a search warrant or a court order.
Outdoor measurements shall not be conducted in the presence of wind speeds greater than twelve miles per hour (12 mph), nor in the presence of precipitation or fog.
D.C. Mun. Regs. tit. 20, r. 20-2904