What is lumen depreciation factor?

Lamp Lumen Depreciation (LLD) is a factor used by lighting designers to predict the depreciation in light output for a specific light source over a defined period. The Lamp Lumen Maintenance Factor (LLMF) expresses the usual reduction of the lumen output over the lifetime.

What is the efficacy of a metal halide lamp?

Metal Halide lights have average efficiency (75-100 lumens/watt source efficiency). They lose out to LEDs principally because their system efficiency is much lower (<30 lumens/watt) due to all of the losses associated with omnidirectional light output and the need to redirect it to a desired area.

How is LLF calculated?

LLF = .85 = RSDD x LDD x BF x LLD LLF (Light Loss Factor) is the product of several factors, each depreciating light output at certain point in time in the future compared to initial light output.

What is lumen maintenance factor?

The amount of light from the light source at a specific time in the future is referred to as the lamp lumen maintenance factor, or LLMF. The lifetime of a LED module is defined as the time it takes until its light output, or lumen maintenance, reaches 70% of the initial output. This is also called L70.

What kind of lumens do metal halide lamps use?

If you have a 1500 watt metal halide lamp, you need to use lumens to find out the equivalent LED lamp. Only then you can convert the old HID to LED. Lumen is the unit of measurement par excellence for brightness. In detail, it applies to spherical illumination and light intensity.

How is lumen depreciation related to LED lighting?

The topic of lumen depreciation is somewhat complex and the experts are not completely in agreement on issues like defining the point when a LED light source should be considered “failed”. With old technology lighting, determining the point that a lamp failed was an easy call.

How long does a metal halide lamp last?

A new 400-watt metal halide lamp is rated to last up to 20,000 hours. Selling points for this lamp also include a color temperature of 4000K and initial lumens at 32,000 to 36,000. This means that the initial light output is extremely high.

Why is there a shortage of metal halide light bulbs?

The culprit was believed to be HID metal halide bulbs which drew too much power and resulted in the shortage. After the incident, the bulbs were updated with $1m worth of LED light bulbs. This is because LED light bulbs are: Safer – they won’t blow like HIDs and contain no mercury.

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