Section 1028 - Performance Requirements(a) Siren Functions. Electronic sirens shall have a wail function and may also have manual and yelp functions. No other function is permitted on sirens sold after January 1, 1982, except for voice communication. Sirens shall meet the following requirements in addition to the sound levels specified in Table I: (1) Wail. The wail function shall have an automatic undulating pitch rate of not less than 10 nor more than 30 oscillations per minute. The sound level shall not drop more than 10 dB(A) below the required values in Table I during the lowest portion of any cycle.(2) Manual. Electronic sirens manufactured after January 1, 1982, which include a manual function shall use the vehicle horn ring or any other manual momentary contact switch to allow the vehicle operator to switch between the wail and yelp functions, to momentarily override the descending sound pattern of the automatic cycle when the control is set at "wail," or to produce a manually-cycled wail when the control is set at "manual."(3) Yelp. The yelp function shall have an automatic undulating pitch rate of not less than 150 nor more than 250 oscillations per minute, except for sirens sold prior to July 1, 1980.(b) Sound Level Output. Two classes of sirens, A and B, are established based on the A-weighted sound level output measured at the angles specified in Table I. The sound level measurements of electronic sirens shall be started immediately after the siren has been operated for one minute. A deviation of 1 dB(A) below the specified value shall be allowed at any three of the eleven test points.Table I. Minimum A-Weighted Sound Level at 3.0 m (9.8 ft) Rotation deg left and right from axis | Sound Level, dB(A) Class A | Class B |
0 | 120 | 115 |
10 | 119 | 114 |
20 | 118 | 113 |
30 | 117 | 112 |
40 | 115 | 110 |
50 | 113 | 108 |
(c) Siren Classification. The A or B overall classification of a siren shall be the class of the lowest performing function incorporated in the siren. The reported sound level for each test point under manual operation shall be the steady-state level reached during continuous activation. The reported sound level for the wail and yelp functions at each test point shall be the average of the levels reached by five consecutive major peaks.(d) Frequency Requirements. The maximum sound level in the axis of the siren shall occur in either the 1000- or the 2000-Hz octave bands for all functions.(e) Electronic Siren Wattage. The wattage drawn by speakers of electronic sirens shall not exceed the following requirements when tested at the voltages specified in Section 1027(b) of this article. The voltage leads of the wattmeter shall be connected to the speaker terminals on the amplifier, and readings shall be taken in the order of manual, wail, and yelp. (1) At the voltage specified for the sound level tests, the measured wattage after 1 min and before 3 min of operation shall not exceed the rating of the driver.(2) At the voltage specified for wattage tests, the wattage shall not exceed 105% of the rating of the driver when measured after 10 min of operation.(3) The wattage recorded for wail and yelp shall be the mathematical average of the high and low readings of five continuous cycles as the signal varies.Cal. Code Regs. Tit. 13, § 1028
1. Editorial correction of NOTE (Register 81, No. 44). Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 26103 and 26104, Vehicle Code.
1. Editorial correction of NOTE (Register 81, No. 44).