[Code of Federal Regulations]

[Title 49, Volume 4]

[Revised as of October 1, 2005]

From the U.S. Government Printing Office via GPO Access

[CITE: 49CFR210.25]



[Page 61]

 

                        TITLE 49--TRANSPORTATION

 

       CHAPTER II--FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF 

                             TRANSPORTATION

 

PART 210_RAILROAD NOISE EMIS SION COMPLIANCE REGULATIONS

--Table of Contents

 

                    Subpart B_Inspection and Testing

 

Sec. 210.25  Measurement criteria and procedures.



    The parameters and procedures for the measurement of the noise 

emission levels are prescribed in the Standards.

    (a) Quantities measured are defined in Sec. 201.21 of the 

Standards.

    (b) Requirements for measurement instrumentation are prescribed in 

Sec. 201.22 of the Standards. In addition, the following calibration 

procedures shall be used:

    (1)(i) The sound level measurement system including the microphone 

shall be calibrated and appropriately adjusted at one or more nominal 

frequencies in the range from 250 through 1000 Hz at the beginning of 

each series of measurements, at intervals not exceeding 1 (one) hour 

during continual use, and immediately following a measurement indicating 

a violation.

    (ii) The sound level measurement system shall be checked not less 

than once each year by its manufacturer, a representative of its 

manufacturer, or a person of equivalent special competence to verify 

that its accuracy meets the manufacturer's design criteria.

    (2) An acoustical calibrator of the microphone coupler type designed 

for the sound level measurement system in use shall be used to calibrate 

the sound level measurement system in accordance with paragraph 

(b)(1)(i) of this section. The calibration must meet or exceed the 

accuracy requirements specified in section 5.4.1 of the American 

National Standard Institute Standards, ``Method for Measurement of Sound 

Pressure Levels,'' (ANSI S1.13-1971) for field method measurements.

    (c) Acoustical environment, weather conditions, and background noise 

requirements are prescribed in Sec. 201.23 of the Standards. In 

addition, a measurement tolerance of 2 dB(A) for a given measurement 

will be allowed to take into account the effects of the factors listed 

below and the interpretations of these effects by enforcement personnel:

    (1) The common practice of reporting field sound level measurements 

to the nearest whole decibel;

    (2) Variations resulting from commercial instrument tolerances;

    (3) Variations resulting from the topography of the noise 

measurement site;

    (4) Variations resulting from atmospheric conditions such as wind, 

ambient temperature, and atmospheric pressure; and

    (5) Variations resulting from reflected sound from small objects 

allowed within the test site.