California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 4 - Special Equipment
Article 9 - Exhaust System Noise Measurement
Section 1032 - Instrumentation

Universal Citation: 13 CA Code of Regs 1032

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

Equipment used in making exhaust system sound level measurements shall meet the following requirements:

(a) Sound Level Meter. A sound level meter complying with ANS S 1.4-1971, issued by the American National Standards Institute, Inc., 1430 Broadway, New York, NY 10018, shall be used to measure the exhaust noise. Type 1 or S 1 A sound level meters shall be used for exhaust system manufacturers' certifications. Type 1, S 1 A, 2, or S 2 A sound level meters shall be used by licensed muffler stations and enforcement personnel.

(b) Tachometer. A tachometer shall be used to determine the rpm ranges specified in Section 1036(c) of this title.

(1) Characteristics. Tachometers shall have the following characteristics:
(A) Accuracy of ± 100 rpm over a range of 2,200 to 5,000 rpm.

(B) A scale of at least 3 in. (76 mm) graduated in increments of not more than 100 rpm, or a digital readout, and a full-scale reading of at least 6,000 rpm.

(C) Capability for operation on all common 6- and 12-V ignition systems, and direct reading on 1-, 2-, 4-, 6-, and 8-cylinder engines with 2- or 4-stroke cycles. Separate instruments may be used to cover the required range of engine types.

(D) Solid-state circuitry with radio frequency suppression.

(E) Attachment to the engine by direct connection to coil, distributor, or tachometer terminal, or by clamping an inductive pickup with shielded cable over one spark plug wire.

(F) Operative ambient temperature range of 32° to 122° F (0 to 50° C), storage temperature range of 0° to 160° F (-17.8° to 71.1° C), and ambient relative humidity range of 10 to 90%.

(G) Capability for calibration checks and adjustments. If an external calibrator is used, it must be provided with the instrument or be readily available in the station.

(2) Instructions. Instructions for proper use and for maintaining correct calibration shall be provided by the instrument manufacturer.

(c) Calibrator. An acoustic calibrator of the coupler type, accurate to within ± 0.5 dB, shall be available for calibration of sound level meters.

(d) Windscreen. An open-cell, foam windscreen recommended by the manufacturer of the sound level meter shall be used to protect the microphone.

1. Amendment filed 6-16-77; designated effective 7-15-77 (Register 77, No. 25).
2. Amendment of subsection (a) filed 8-20-81; effective thirtieth day thereafter (Register 81, No. 34).

Note: Authority cited: Section 27150.2, Vehicle Code. Reference: Sections 2500- 2504, 2540- 2549, and 27150.2, Vehicle Code.

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