Luminaire 'Types' for parking lot lighting

Parking facility lighting luminaires are selected based on photometric distribution to specific areas of the lot surface.


Architectural luminaires blend with the total architectural design of the facility. Generally, they achieve efficient and uniform light distribution through reflectors and refractor lenses.

Pole-mounted luminaires can provide illumination at distances of two to two-and-a-half times the mounting height from the pole.

Post-top luminaires offer symmetrical and asymmetrical distribution, in either direct or indirect design. The mounting height is usually limited to no more than 26 feet.

Indirect type luminaires shield the light source from normal view, thus providing excellent glare control along with a good aesthetic appearance. These types of luminaires are used for parking lot lighting and hold lamps of 250W or greater, with a mounting height of 20 feet or more.

High mast systems have a mounting height of 66 feet or more and can cover a large area with a minimum number of poles. Suitable for nonresidential areas, the luminaires of a high mast system can provide symmetrical or asymmetrical distribution using refractors and/or reflectors, or the distribution can be totally indirect.

Roadway fixtures provide a wide range of symmetrical and asymmetrical distributions. The wall-mounted unit is applicable to a narrow area between buildings. The mounting height is usually no more than 26 feet. A wide variety of distribution types are available, generally divided in cutoff and semi-cutoff distribution design.

Determining Light Loss Factor

From the Illuminating Engineering Society North America Lighting Handbook:

The light loss factor (LLF) is a fraction that represents the amount of light that will be lost due to things such as dirt on lamps, reduction of light output of a lamp over time, and similar factors. The following items are the individual components of the light loss factor.The total LLF is calculated by multiplying all the individual factors together. No factor should be ignored (set equal to 1) until investigations justify doing so. Lighting calculations should not be attempted until all light-loss factors are considered.

•Luminaire Ambient Temperature Factor
•Heat-extraction thermal factor
•Voltage-to-luminaire factor
•Ballast Factor
•Ballast-lamp photometric factor
•Equipment operating factor (H.I.D. only)
•Lamp-position (tilt) factor (H.I.D. only)
•Luminaire surface depreciation factor


•Lamp Lumen Depreciation
•Luminaire Dirt Depreciation
•Room Surface Dirt Depreciation
•Lamps Burnout Factor