{"data":{"id":"us/33-cfr-84.14","jurisdiction":"us","citation":"33 CFR 84.14","heading":"Intensity of lights.","body":"(a) The minimum luminous intensity of lights shall be calculated by using the formula:\nI = 3.43 × 10 6 × T × D 2 × K−D\nWhere:\nI is luminous intensity in candelas under service conditions,\nT is threshold factor 2 × 10−7lux,\nD is range of visibility (luminous range) of the light in nautical miles,\nK is atmospheric transmissivity. For prescribed lights the value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.\n(b) A selection of figures derived from the formula is given in the following table (Table 84.14(b)):\nTable 84.14(b)\nRange of visibility (luminous range) of light in nautical miles D Minimum luminous intensity of light in candelas for K = 0.8 I\n1 0.9\n2 4.3\n3 12\n4 27\n5 52\n6 94","path":["Title 33—Navigation and Navigable Waters","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER E—INLAND NAVIGATION RULES","PART 84—ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES"],"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":"4b9ec5e5ed535d61ffec277f4dae9d347262168b8369384bfef1010ef40fd649","source_id":"us-cfr","stale":true,"prev":"us/33-cfr-84.13","next":"us/33-cfr-84.15"},"notice":"GroundRules: Original legal text. Not legal advice."}