What is Photometric Lighting Analysis?
A Photometric Lighting Analysis is a way to view a proposed lighting solution and light output over a given (indoor or outdoor) area prior to purchasing LED Fixtures or Retrofit Solutions. Using photometric software, an indoor or outdoor room or area layout can be entered (or imported), designed and adjusted. Lighting engineers, using the software, can input fixtures at specific locations, angles, orientation and height within the software to represent where the fixtures would be installed in the area.
The lighting software then calculates light levels (foot candles) based on that data and provides a comprehensive visual layout and report. The report displays calculation points representing the foot candle reading at that location.
Purchasing LED Lights and finding the light levels spotty or inadequate
This is a huge problem in the lighting industry. Facilities are looking to convert to LED lighting, so they go online to a large online retailer and look at the products being offered. They make their best educated guess at what light they should use, purchase it, and install it. Now comes the painful discovery.
- It’s too bright
- It’s not bright enough
- The light is not uniform
- The light is bright under the light, then goes dark, and then brightens up under the next light.
How were you supposed to know what the outcome was going to be? After all, the light appeared to be exactly what you needed, and aren’t all lights basically the same?
Well, the truth is, LED Lighting can be as different as cars in a dealership. And you need to understand lumens, foot candles, beam angles to determine what will be the best lighting option.
But you’re not a lighting engineer. How are you supposed to know all this? You’re not, and that why there are tools that are designed to show you the results BEFORE you purchase. It takes the risk out of purchasing lights.
How to understand your current light levels
To understand light levels, lets introduce the concept of foot candles or lux. They are basically the same thing, just light measurements, and readings can be taken using a simple light meter or a light meter app installed on a smart phone. A dedicated light meter will give you better results, but its OK to use a free light meter app to get an understanding of the light in your location.
For example, you may have a production facility and are looking to upgrade to LED Shop Lights. A good process would be to install a light meter app on your phone, and use it to take several readings around your facility. Go under a light, go between lights, go into the center of the space, go to the edge, and take readings.
From this, you will get a good idea what your current lighting is performing, and your current light levels. But you can also determine:
- Are my light levels OK, too bright or too dim?
- Are my light levels pretty uniform and evenly distributed?
- Would I like to improve the light levels, or are things OK.
Understanding the Basics on Lighting
1. What is a lumen?
A lumen is a unit of light. By itself its useless, but it becomes useful when it defines the collective lumens produced by 1 fixture or bulb.
2. What is a foot candle?
A foot candle is a measurement of light at a specific location, and 1 to many lights can contribute to the specific foot candle reading at that location. Foot candles (or its equivalent LUX) is a requirement that most are looking for when they describe a light level for a project, facility or location.
3. What is a Beam Angle?
A fixture produces lumens. How it is focused requires optics, or the lack of optics. Typically, lights mounted very high require optics to focus the light to where its needed (the ground, for example). However, adding a tight optic to a light and mounting it at a low height produces spotty lighting, with intense bright spots and dull areas in between the lights.
So not having the right amount of lumens and the improper beam angle will provide poor lighting. That is why its important to understand what your foot candle requirements are, and then picking the correct fixture producing the perfect amount of lumens with the optimum beam angle.
Photometric Studies – For indoor and outdoor applications
Photometric studies can be done for indoor and outdoor locations, whether its a warehouse, parking lots, baseball field, school gymnasium or office location. They can be developed from CAD files, or for outdoor locations, using google maps.
An Indoor Factory Photometric Study
In this study, the customer’s current lighting was averaging around 12 foot candles. They approached MyLEDLightingGuide for an upgrade to LED, but like most large customers, wanted to take the first step and perform a light analysis. They wanted more light, they wanted to save energy, and they were tired of changing out bulbs and ballasts.
The customer provided MyLEDLightingGuide with a CAD file (.dwg file) and we imported it into our software. We modeled 1 area, replacing their HID lighting with a combination of 120 Watt and 200 Watt LED High Bays. In the main work area, we increased their foot candles from 12 to 41! Average Min Ratio of 2.31 indicates uniform light levels through out the space.
Being able to complete this project for the customer allows them to see the results before spending $1.
An Outdoor Street Lighting Photometric Study
This is an example of a DOT application, replacing 1500W High Pressure Sodium lights with 600W LED High Mast Area Lights with 150 degree optics. The Iso-lines represent foot candle transitions, with the red-line highlighting 0.6 foot-candles. Photometric studies allow customers to see how the lights will perform before having to commit, and allows for the lights lumens and optics to be adjusted to meet the specifications or desired amount.
An Outdoor Sport Court Photometric Study
Sometimes the requirements come on a piece of draft paper, with pole locations, heights, and dimensions. In the particular case, we achieved uniform lighting across the court and offered exceptionally bright lighting for night play, well still saving the customer over 50% on the lighting bills on top of improving their light levels
Want us to do a photometric study for you and take the risk out of converting to LED Lights? Its simple, contact us or simply call us at 888.423.3191. Almost always, we provide this service free of charge.