What is illumination factor?
It may be defined as “the ratio of illumination under normal working condition to the illumination when everything is clean or new” i.e. D.F = Illumination under normal working conditions / Illumination when everything is clean. The maintenance factor is based on how often the lights are cleaned and replaced.
How do you calculate luminance factor?
Alternatively, the luminance of a surface can be calculated from the formula L = E x § / ¹ where § is the luminance factor of the surface material and is read from a table of values. If the surface is diffuse then § can be replaced with “p”, the diffuse reflection coefficient for the material.
How is luminance defined?
Definition of luminance 1 : the quality or state of being luminous. 2 : the luminous intensity of a surface in a given direction per unit of projected area.
What is the formula for illumination?
Illuminance is the Luminous Flux per unit area of incident radiation away from the light source. (unit:Lux,lx) Illuminance can be considered the Flux within one square meter. lx = lm/ m2.
What is illumination absorption factor?
The Absorption is the “missing piece”, when comparing the total reflected and transmitted energy with the incident energy. The ratio of the total absorbed radiant or luminous flux to the incident flux is called absorptance (formerly also absorption factor).
What is illumination unit?
Lux (abbreviation lx): The SI unit of illumination value; it is equal to one lumen per square metre.
How do you calculate luminance contrast?
The equation is of the form C = 125 (Y2 − Y1)/(Y1 + Y2 + 25). C is equal to the calculated contrast, and Y1 and Y2 refer to the luminous reflectance values (LRV) of the two surfaces to be calculated. Y1 is to be darker than or equal to Y2.
What is unit of luminance?
The SI unit for luminance is candela per square metre (cd/m2), as defined by the International System of Units (SI is from the French Système international d’unités) standard for the modern metric system. A non-SI term for the same unit is the nit.
How is illumination distance calculated?
Finding the Cosmological Distance You can multiply the light travel time (converted into seconds, as in the first section) by the speed of light to find the distance traveled by the light itself.
What is absorption factor?
absorption factor (plural absorption factors) The measurement of a specific substance’s ability to absorb radiant energy; absorptivity.
What is light loss factor?
• A Light Loss Factor is a multiplier that is used to predict future performance (maintained illuminance) based on the initial properties of a lighting system. • LLF = 1 – Expected Depreciation. • The Total LLF is determined by multiplying the independent effects of. multiple factors.