Determining Basic Application Criteria

Tailoring light to specific environments with the Form Ten optical system is a straightforward process which, properly followed, inevitably leads to good visibility.

Minimum Maintained Footcandles are good lighting design criteria. Specifying minimum footcandles will provide predictable results that can be verified.

The use of average footcandles as a criteria is of questionable value from a performance specification viewpoint since averages can be distorted through calculations, and cannot be confirmed through field measurements.

Good pavement luminance is the desirable feature of a lighting system since the professional designer's intent is for pavement brightness (luminance) with uniformity.

Through a series of many field evaluations Gardco has determined that a maximum to minimum footcandle uniformity ratio of approximately 10:1 to 15:1 is a good guide for providing favorable visual intensities on most parking areas.

Perfectly uniform illumination such as a 1:1 maximum to minimum ratio would not guarantee pavement brightness uniformity. This is due to directional pavement reflectance characteristics. (The pavement may actually appear darkest directly under each luminaire.) Likewise, areas of too great a difference in illumination uniformity, such as to exceed 15:1 maximum to minimum ratio, would appear to be dark at the midpoint areas between poles.