Question 1

What is a good light loss factor?

Accepted Answer

In reality, there is no unified standard within the industry; furthermore, neither the Illuminating Engineering Society (IES) nor the International Commission on Illumination (CIE) standards define a specific ideal range for LLF (Lamp lumen depreciation factor) and MF (Maintenance factor) values. ZGSM considers a range of 0.8 to 0.9 to be reasonably appropriate—a determination that relies heavily on achieving low rates of lamp lumen depreciation and luminaire dirt depreciation. Since both types of factors are time-dependent, the shorter the project duration, the higher the LLF value; conversely, the longer the project duration, the lower the LLF value. This further underscores the necessity of clearly specifying both the intended service life of the luminaires and their operating environment when comparing the relative quality of LLF values; without such context, such comparisons lack practical significance.

Question 2

Is Light loss factor same as maintenance factor?

Accepted Answer

The Light loss factor (LLF) is commonly referred to as the Maintenance factor. Both serve as multipliers—typically ranging between 0 and 1—used in lighting design calculations to quantify the degree to which a lighting system's light output diminishes over time due to factors such as dust accumulation, lamp aging, and component failure. Naturally, as they are defined by different standards, there are some minor distinctions between the two; beyond the time-dependent calculation factors, the LLF also incorporates other influencing variables such as the Lamp ambient temperature factor (LATF), the Luminaire voltage factor (LVF), and the Luminaire component depreciation (LCD). In professional practice, however, the "Maintenance Factor" is the more prevalent term and is widely utilized in lighting simulation and design applications.

Question 3

What are recoverable and non-recoverable factors for LLF?

Accepted Answer

The various factors influencing the Light loss factor (LLF) are categorized into recoverable and non-recoverable factors. Recoverable factors refer to light loss that can be reduced—or even eliminated—through maintenance measures such as cleaning fixtures or replacing light sources; a clear example of this is Lamp lumen depreciation (LLD). Non-recoverable factors, conversely, stem from inherent, fixed conditions and cannot be mitigated through routine maintenance; examples include ambient temperature and voltage fluctuations. The classification of LLD itself is somewhat more complex: for LED fixtures featuring replaceable light sources, we consider it a recoverable factor; however, for LED fixtures with non-replaceable light sources, we classify it as a non-recoverable factor.

LED Street Light

High Mast Light

Led Flood Light

Solar Flood Light

LED High Bay Light

LED Tunnel Light

LED Garden Light

Led Bollard Light

Solar Street Light

LED Traffic Light

LED Canopy Light

Lighting Accessories

Smart Systems

Simulation Design

Smart Financing

Light loss factor vs maintenance factor

Get In Touch

Category

Don't Want to Miss Anything?

LED Street Light

High Mast Light

Led Flood Light

Solar Flood Light

LED High Bay Light

LED Tunnel Light

LED Garden Light

Led Bollard Light

Solar Street Light

LED Traffic Light

LED Canopy Light

Lighting Accessories

Smart Systems

Simulation Design

Smart Financing