What is depreciation factor in relation to lighting?

The depreciation factor in relation to lighting refers to the reduction in luminous output of a lighting fixture over time due to factors such as lamp aging, dirt accumulation, and environmental conditions. It quantifies how much the effective illumination decreases compared to the initial brightness. This factor is crucial for ensuring that lighting designs maintain adequate illumination levels throughout their lifespan, necessitating periodic maintenance or replacement of fixtures. Understanding the depreciation factor helps in planning for energy efficiency and optimal lighting performance.