---
kind: "section"
citation: "33 C.F.R. § 67.10-20"
title: "33"
number: "67.10-20"
heading: "Sound signal tests."
url: "https://uscodex.org/cfr/33/67.10-20"
---

# §67.10-20. Sound signal tests.

- (a) **Sound signal tests must—**
  - (1) Be made by the applicant in the presence of a Coast Guard representative, who certifies the test if the procedures comply with the requirements of this section;
  - (2) Be made with Coast Guard supplied and calibrated sound level meters and power meters; and
  - (3) Be made in an anechoic chamber large enough to accommodate the entire sound signal, as if installed for actual use.
- (b) The sound pressure level must be measured as a function of:
  - (1) Distance by using a sufficient number of points to allow a far-field extrapolation of the sound pressure level;
  - (2) Power at outputs up to and including the approximate power level necessary to comply with [§ 67.10-1(c)](/cfr/33/67.10-1.md?p=c);
  - (3) Horizontal angle at increments not greater than 30°; and
  - (4) **Harmonic content to at least the third harmonic.**
- (c) In analyzing the test data to determine the minimum power necessary to produce the sound pressure level specified in Table A of this section the Coast Guard follows the procedures prescribed by the International Association of Lighthouse Authorities (IALA) in Supplement No. 3 to the IALA Bulletin of February 1969 for analysis of harmonic components and does not consider components above 1,100 Hertz as adding to the audible range.

## Notes

### Source

Source: CGD 72-74R, 37 FR 13512, July 8, 1972, unless otherwise noted.

### Authority

Authority: 14 U.S.C. 503, 544; 43 U.S.C. 1333; DHS Delegation No. 00170.1, Revision No. 01.4.

### Source

Source: CGFR 58-17, 23 FR 3377, May 20, 1958, unless otherwise noted.