Check Light ™
RP-8   Photometric Comparator
Beta Version     1.10

CheckLight is a verification program that matches your specific photometric file to the IESNA RP-8 lighting standard. CheckLight works independently of lighting technology, and it helps to quickly verify equivalency of new replacement to previous lighting.  Learn more about the RP-8 standard here.  See a CheckLight sample output.   
CheckLight uses an IES file from a directory on your computer.
Input your IES Photometric file below (from your computer)


 
Choose the appropriate categories on the right and CheckLight will assign RP-8 illuminance values.  Calculations appear in a second browser window after clicking "Calculate".   You may switch back and forth between these windows, revisit this page, load different IES files and change settings as required.  Resultant wattage and quantity may be input to an ROI payback calculator.

The preset values evolved from RP-8.  Click for References in another window

Roadway Type, Pedestrian Conflict Area and Pavement Classification are IESNA categories that are combined to select illuminance.  Click the heading to the right for full description, use browser back button to return.

Min. Uniformity Factor  Since the area defined by the table will usually exceed the lighted area, a minimum setting multiplier is provided to define that outer limit.  This multiplier limits the lowest value that will be used in the Uniformity Ratio calculation, e.g. a multiplier of 0.1 limits the minimum for an outdoor parking lot to 0.02 footcandles, or 0.1 footcandles for a parking garage.  The designer must provide a lighting layout with sufficient overlap to bring this boundary up to minimum illuminance levels.

Mounting Height  This value is used to calculate all angles for illuminance.  Limit is 8 to 120 feet.

Cutoff  defines the output limits from 80° to 90° and, 90° and higher.  See Cutoff Defined.

Candela Multiplier factors all candela in the IES file to scale up or down.   Used when a single file is supplied for a family of luminaires, needing only a multiplier above or below the base lumens, usually provided.  Wattage and relative lumens display are changed accordingly.

Rotate Luminaire  allows rearranging lighting peaks or lobes to other horizontal positions.  Note the display has different band widths: the 90° and 270° bands are centered within a 45° swath, while the 0° and 180° are centered within 90°.  Rotate can allow a finer resolution with a Type-I distribution, for example, but has little or no effect with symmetrical outputs such as type-5.

Show Candela / File Headers  are display options having no effect on analysis.
Roadway Type
Local  Collector
Major  Expressway
Freeway Class A 
Freeway Class B
Pedestrian Conflict Area
Low  Med. High 
Pavement Classification
R1  R2/R3 R4 
Min. Uniformity Factor
× Min. Horiz. FC
.05   -  .5
Mounting Height Ft
8 ft  -  100 ft
Candela Multiplier
0.00001 - 100
Rotate Luminaire
No  90°  180°
Show Candela Table
No   Yes  
Show IES File Headers
No    Yes

This service provides a quick, simple assessment of lighting comparison to ascertain minimum
wattage and luminaire count. The intended purpose is improved data for calculation of ROI and payback.
Seek a thorough lighting layout by a professional before committing a lighting project.

 © 2011 Patrick Mullins, all rights reserved