Annex I · 8 — Intensity of lights

(a) The minimum luminous intensity of lights shall be calculated by using the formula: I = 3.43 x 106 x T x D2 x K-D Where I is luminous intensity in candelas under service conditions, T is threshold factor 2×10-7 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: Range of visibility (luminous range) of light in nautical miles Luminous intensity of light in candelas for K = 0.8 D I 1 0.9 2 4.3 3 12 4 27 5 52 6 94

NOTE: The maximum luminous intensity of navigation lights should be limited to avoid undue glare. This shall not be achieved by a variable control of the luminous intensity.