{"data":{"id":"us/33-cfr-67.10-20","jurisdiction":"us","citation":"33 CFR 67.10-20","heading":"-20 Sound signal tests.","body":"(a) Sound signal tests must:\n(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;\n(2) Be made with Coast Guard supplied and calibrated sound level meters and power meters; and\n(3) Be made in an anechoic chamber large enough to accommodate the entire sound signal, as if installed for actual use.\n(b) The sound pressure level must be measured as a function of:\n(1) Distance by using a sufficient number of points to allow a far-field extrapolation of the sound pressure level;\n(2) Power at outputs up to and including the approximate power level necessary to comply with § 67.10-1(c);\n(3) Horizontal angle at increments not greater than 30°; and\n(4) Harmonic content to at least the third harmonic.\n(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.","path":["Title 33—Navigation and Navigable Waters","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER C—AIDS TO NAVIGATION","PART 67—AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES","Subpart 67.10—General Requirements for Sound signals"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-33.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:25:35Z","sha256":"dbaac38e2300e0727dfe87cdceaf98d8290252a7a0df6a99f3d72a6e2f949a18","source_id":"us-cfr","stale":true,"prev":"us/33-cfr-67.10-15","next":"us/33-cfr-67.10-25"},"notice":"GroundRules: Original legal text. Not legal advice."}