Code of Federal Regulations (Last Updated: November 8, 2024) |
Title 49 - Transportation |
Subtitle B - Other Regulations Relating to Transportation |
Chapter III - Federal Motor Carrier Safety Administration, Department of Transportation |
SubChapter A - General Regulations |
Part 325 - Compliance With Interstate Motor Carrier Noise Emission Standards |
Subpart C - Instrumentation |
§ 325.23 - Type of measurement systems which may be used.
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§ 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:
(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.