California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 4 - Special Equipment
Article 8 - Sirens
Section 1026 - Microphone and Personnel Stations
Current through Register 2024 Notice Reg. No. 38, September 20, 2024
Sound level meter microphones and technicians shall be stationed as follows:
(a) Microphone Location. The microphone used for testing an electromechanical or electronic siren shall be located 3.00 m ± 6 mm (9.8 ft ± 0.24 in.) from the edge of the siren horn or projector, in line with the siren axis, and at the same height as the siren. The microphone used for testing a mechanical siren shall be located 1.20 m ± 50 mm (4 ft ± 2 in.) above the test surface and 3.00 m 6 mm (9.8 ft ± 0.24 in.) from the nearest part of the siren.
(b) Microphone Orientation. The microphone shall be oriented in relation to the sound source in accordance with the instrument manufacturer's instructions. If the instruction manual does not include adequate information, a specific recommendation shall be obtained from the manufacturer.
(c) Personnel Location. During laboratory tests, technicians and observers shall remain outside the anechoic chamber. During field tests, persons other than the operator of the vehicle shall be positioned no closer than 3 m (9.8 ft) from the microphone or the siren.
1. Editorial correction of NOTE (Register 81, No. 44).
Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 26103 and 26104, Vehicle Code.
