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Why Do Fluorescent Lamps and Ballasts Fail?

Just like any manufactured product, fluorescent lamps are not infallible.


Sometimes you may have a bad batch of product where something happened during the manufacturing system causing them not to last as long as they should. Or maybe a building experiences a freak electrical surge, causing the fluorescent lamp and/or ballast to stop working.


However, if you're knowledgeable about what some of the reasons are for potential issues with fluorescent lamps and ballasts, then you can do what you can to try to safeguard against problems arising. Additionally, due to the fact that fluorescent lamps do include a small amount of mercury in them, it's important to know how to dispose of burned out lamps properly.

Why a Fluorescent Lamp May Fail

How long a fluorescent lamp is usually determined by the manufacturer. At ShineRetrofits.com, we carry lamps that last from under 10,000 hours to over 50,000 hours. There are a number of factors that help determine just how long a fluorescent lamp will live -- how it's made, the conditions in which it operates, and the control circuit being used.


A fluorescent lamp that is on its death bed will normally show a few signs. One is the light it emits may being to flicker, the color may start to appear off, and it may even go out entirely in certain areas of the bulb. Another telltale sign is if ends of the lamp turn black.


Failed Electrodes

One part of the fluorescent lamp that might eventually fail are the electrodes (aka filaments or cathodes) that are located at either end of the lamp's tube. When electricity flows into the lamp, those electrodes create an electrical arc from which spring electrons that flow through the gases inside the lamp. They eventually hit the atoms of mercury inside the lamp, causing them to produce wavelengths of UV light. That UV light is then absorbed by the phosphor coating lining the inside of the lamp's tube, and they begin to glow, making the lamp emit light.


If the filaments in the lamp are not working, an electrical current can longer get into the lamp to stir up the necessary electrodes. Plus there is now no heat to turn the mercury liquid inside the lamp into vapor, which is another necessary step.


"Emission Mix"

Another reason why a fluorescent lamp may fail is again related to the electrodes or filaments on either end of the lamp. This time it's about the "emission mix" on the filaments that get the electrons going and moving through the gas inside the lamp's tube. Every time the lamp is turned on and electrons are made, the emission mix is used.


Now, you may think the more a fluorescent lamp is used, the more mix will be lost. However, it's the direct opposite. Every time a fluorescent lamp is turned on in a cold state, more emission mix is used to get it going. That means lamps that are turned on for lesser periods of time -- usually less than a three-hour time period -- will find themselves burning out due to less emission mix than those that are kept on for a longer time.


Loss of Phosphors

Eventually as the lamp is used, the performance of the phosphor coating that lines the insides of the lamp's tube will start to dwindle. You can normally tell this is starting to happen when you notice the light emitted from the lamp is not as bright as it once was, or you've installed a new fluorescent lamp next to an older one and can see the difference.


Loss of Mercury

As you know, all fluorescent lamps include a small amount of mercury liquid inside them. And it is this mercury liquid that when formed into a vapor is one of the most important players in allowing the lamp to illuminate. Over time, as the mercury liquid is changed into a gas, some of that gas will become permanently absorbed into the phosphor coating, or it be even be absorbed by the glass tube itself or the electrodes on either end. And being lamps are now being made with lower amounts of mercury than in the past, this has now started to be seen more as a reason for a lamp to go out. When a fluorescent lamp is beginning to lose its mercury, you can tell as the light it emits will begin to look pink.

Disposing of a Fluorescent Lamp

So if you find yourself with a fluorescent lamp you now need to dispose of, what's the proper and environmentally-conscious way to do so?


According to the US Environmental Protection Agency, lamps that contain mercury are regulated by the Resource Conservation and Recovery Act (RCRA) Universal Waste Rule (UWR) and Subtitle C hazardous waste regulations. Because of that, there are certain protocols that must be followed when disposing of a fluorescent lamp.


For instance, the EPA has an entire set of rules that must be followed for those handling fluorescent lamps in school buildings. And the EPA also has a National Lamp Recycling Outreach program it developed for the recycling of lamps that contained mercury. Additionally, certain states -- such as California -- have their own rules for how fluorescent lamps should be take care of.


When it comes to compact fluorescent lamps (CFLs), the EPA also has rules and regulations there as well. For instance, the EPA recommends CFLs be disposed as hazardous waste rather than in your general household garbage. They also advise recycling CFLs and mention some states -- including California, Minnesota, and Washington -- require residents to recycle CFLs rather than just throwing them away, where they can be broken in a trash compactor and the mercury inside them released.

Why a Ballast May Fail

Another reason why a fluorescent lamp may fail to work is because there's a problem with the ballast. You can tell your ballast may be going if the light begins to diminish or starts to blink at a rapid pace. Another sign can be if the fluorescent lamp stops working very abruptly -- most of the reasons why a lamp stops working happen over time, so a lamp that just suddenly cuts out may be an indicator of a ballast problem.


How long the electronics inside the ballast is going to last normally depends on what operating temperature you're using. It's important to check what the minimum and maximum operating temperatures are for the ballast you are using based on what the manufacturer recommends. Generally speaking, if you increase the maximum operating temperature by 10°C, you will lower the ballast's life in half.


Additionally, if your ballast is not properly wired to the fluorescent lamps, which can also cause it to malfunction. If you find your ballast seems not to be operating at its peak performance, this may be the cause, especially if it's a new installation.


Another tip to remember -- sometimes a ballast has a control inside where if it begins to overheat, it will automatically shut itself off, taking light with it. Then after it is allowed to cool down for a few minutes, it will turn back on. So before you get rid of your ballast, make sure that's not the issue.



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