49 CFR 325.23 - Type of measurement systems which may be used.

U.S. Code of Federal Regulations

Regulations most recently checked for updates: Sep 16, 2025

View all text of Subpart C [§ 325.21 - § 325.27]

§ 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:

1 Copies of the specification may be secured from the American National Standards Institute, 1430 Broadway, New York, New York, 10018.

(a) A Type 1 sound level meter;

(b) A Type 2 sound level meter; or

(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.