§325.23. Type of measurement systems which may be used.
49 C.F.R. § 325.23
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 Type 1 sound level meter;
A Type 2 sound level meter; or
A Type S sound level meter which has—
A weighing frequency response;
Fast dynamic characteristics of its indicating instrument; and
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.
Notes, amendments, and revision history
Authority
Authority: 42 U.S.C. 4917; 49 U.S.C. 301; and 49 CFR 1.87.
Source
Source: 40 FR 42437, Sept. 12, 1975, unless otherwise noted.