When designing lighting layouts, factoring in the photometric spectrum is a crucial step to get it right. In fact, an uncontrolled light source can give off light rays in every direction, resulting in harmful illumination. Photometric analysis works to detect this excess harmful light and helps contain it by specifying the intensity and the quality of radiation. It helps to come up with techniques to contain it and aim it in areas where it is actually required.
When designing lighting in residential, industrial or institutional projects, a photometric analysis is a prerequisite to control costs and increase the productivity of the light fixtures.
What is Photometry?
Photometry, photometrics, photometric analysis and photometric studies are the different terminologies of the same thing. It is the study of how light leaves a fixture and spreads into its surroundings. Specifically, the science of measuring light as perceived by the human eye. In large projects, photometrics play an important role in allowing lighting designers to understand if the light is enough. It enables in confirming the level of brightness, intensity and more. It also helps in understanding lighting costs and calculating energy requirements.
A photometric report of a parking lot. The image on the left is the exterior scene depicting the lighting design of the space. The image on the right shows the illumination levels in foot-candle.
When do I need it?
When planning for lighting
A photometric analysis would help to determine as to how the lighting design would be more fitting for the space, before the lights are actually purchased. It simply helps to plan ahead before arriving at a buying decision.
When retrofitting lights
Most often, lighting retrofit projects are executed with assumptions. The biggest mistake people make is the one-for-one replacement. Unfortunately, it doesn't create acceptable results. It is widely known that retrofitting an area with a 100W LED fixture by replacing a 400W metal halide area light would give off a brighter light. So, many contractors skip the photometric tests and get to the step of installation, to quickly finish the work. But this can be quite detrimental for the customer's overall satisfaction.
When local codes need to be met
Some local laws require you to make sure that little or no light is trespassing into neighboring commercial or residential properties. Most local legislations prohibit light trespassing of even one foot-candle. It is in these instances, photometric analysis comes to the rescue to meet the local light code.