[Code of Federal Regulations]

[Title 49, Volume 5]

[Revised as of October 1, 2005]

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

[CITE: 49CFR325.23]



[Page 10]

 

                        TITLE 49--TRANSPORTATION

 

                      DEPARTMENT OF TRANSPORTATION

 

PART 325_COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS

--Table of Contents

 

                        Subpart C_Instrumentation

 

Sec. 325.23  Type of measurement systems which may be used.



    The sound level measurement system must meet or exceed the 

requirements of American National Standard Specification for Sound Level 

Meters (ANSI S1.4-1971), approved April 27, 1971, issued by the American 

National Standards Institute, \1\ throughout the applicable frequency 

range for either:

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    \1\ Copies of the specification may be secured from the American 

National Standards Institute, 1430 Broadway, New York, New York, 10018.

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    (a) A Type 1 sound level meter;

    (b) A Type 2 sound level meter; or

    (c) A Type S sound level meter which has--

    (1) A weighing frequency response;

    (2) Fast dynamic characteristics of its indicating instrument; and

    (3) A relative response level tolerance consistent with those of 

either a Type 1 or Type 2 sound level meter, as specified in section 3.2 

of ANSI S1.4-1971.