33 CFR § 84.14 - Intensity of lights.

---
identifier: "/us/cfr/t33/s84.14"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 84.14 - Intensity of lights."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "84.14"
section_name: "Intensity of lights."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "E"
subchapter_name: "INLAND NAVIGATION RULES"
part_number: "84"
part_name: "ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Sec. 303, Pub. L. 108-293, 118 Stat. 1042 (33 U.S.C. 2071); Department of Homeland Security Delegation No. 0170.1."
regulatory_source: "79 FR 37921, July 2, 2014, unless otherwise noted."
cfr_part: "84"
---


# 84.14 Intensity of lights.

(a) The minimum luminous intensity of lights shall be calculated by using the formula:

I = 3.43 × 10
<sup>6</sup> × T × D
<sup>2</sup> × K<sub>−D</sub>

Where:

I is luminous intensity in candelas under service conditions,

T is threshold factor 2 × 10<sub>−7</sub>lux,

D is range of visibility (luminous range) of the light in nautical miles,

K is atmospheric transmissivity. For prescribed lights the value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.

(b) A selection of figures derived from the formula is given in the following table (Table 84.14(b)):

Table 84.14(**b**)

| Range of visibility(luminous range) of lightin nautical miles D | Minimum luminous intensity of light in candelas for K = 0.8 I |
| --- | --- |
| 1 | 0.9 |
| 2 | 4.3 |
| 3 | 12 |
| 4 | 27 |
| 5 | 52 |
| 6 | 94 |