Field measurements of open and covered parking facilities are addressed. This information is useful to designers, owners, and operators of parking facilities in evaluating the performance of applicable lighting systems.

 

This Guide replaces and revises the previous edition last published in 1991. The major changes from the 1991 Guide are inclusion of the basic requirements from IESNA RP-20-98 Lighting for Parking Facilities, which now recommends minimum values of horizontal and vertical illuminance as well as maximum to minimum ratios of horizontal illuminance. In addition, the number of measurements required to determine average horizontal illumination (optional) was reduced while the accuracy of such field evaluations was preserved.

 

The results of field photometry are subject to greater variability than laboratory measurements because of the adverse test conditions encountered. Therefore, this Guide recommends recording all existing conditions at the time of the test, such as supply voltage, lamp wattage, lamp operating position, atmospheric conditions, luminaire mounting height, luminaire orientation, distances from pole center to lamp centers, and any other factors which might affect the results. Following a brief introduction, the main sections of this Guide are: conditions of test noting all existing conditions (optical and electrical) at the time of test; test equipment describing the photometric and electrical devices required; test procedures surveying the parking facility and laying out a grid of measuring points; and test report citing what data must be gathered to facilitate later analysis.

This Guide also features an annex containing five figures adapted from IESNA RP-20-98. These figures illustrate methods of measuring illuminance levels and making photometric evaluations in parking lots and garages. Note however, this Guide does not cover special lighting applications (i.e., lighting for closed circuit television monitoring or security lighting).