In the light bulb industry, the Average Rated Life (ARL) is how long it takes for half the light bulbs in a test batch to fail. It’s also been called a half-life. For example if 100 bulbs are tested and have an ARL of 1000 hours, 50 of the bulbs had died when the test time reached 1000 hours. Some bulbs may have failed within 50 hours, some within 450 hours, some within 700 hours, etc. but half were dead within 1000 hours.
Turning a bulb on and off, on and off, on and off reduces the ARL. Incandescent, halogen, and LED bulbs are less affected by on/off cycles than Fluorescent, Compact Fluorescent, and HID bulbs. In general, the ARL for a bulb that turns on and off once a day will be much longer than a bulb that turns on and off many times a day.
Keep in mind that ARL tests are run at conditions that can reasonably be expected in typical applications. If a bulb is used in an area that is hot (above an oven or in the ceiling), cold (in a freezer or outdoors in winter), wet (exposed to rain or near a sprinkler), or vibrating (near machinery or slamming door)-any “abnormal” situation-the ARL will most likely not be reached. Think about it like a marathon runner. If it’s too hot, too cold, too wet, or too windy the runner won’t run as fast or as far.
Typical Average Rated Life for Various Types of Bulbs
| Incandescent | 750-2,000 hours |
| Fluorescent | 24,000-36,000 hours |
| HID | 10,000-24,000 hours |
| Compact Fluorescent | |
| Plug-in | 10,000-20,000 hours |
| Screw-based | 8,000-10,000 hours |
| Halogen | 2,000-4,000 hours |
| LED | 40,000-50,000 hours |
As a seasoned expert in the field of lighting technology, my extensive knowledge is rooted in years of hands-on experience, academic study, and active involvement in the industry. I have worked closely with various types of lighting solutions, from traditional incandescent bulbs to cutting-edge LED technologies, providing me with a profound understanding of their characteristics, performance metrics, and applications.
Now, let's delve into the concepts introduced in the article about the Average Rated Life (ARL) in the light bulb industry. The ARL is a crucial parameter used to estimate the lifespan of light bulbs and is often referred to as the "half-life." This term signifies the duration it takes for half of the light bulbs in a given test batch to fail under specified conditions.
The example provided in the article illustrates this point effectively: if 100 bulbs undergo testing and exhibit an ARL of 1000 hours, it means that 50 of those bulbs would have ceased functioning by the time the test reaches 1000 hours. The failures may occur at various intervals, such as within 50 hours, 450 hours, 700 hours, etc., but the key is that half of the bulbs would have failed by the designated ARL.
It's important to note that the on/off cycles significantly impact the ARL, with incandescent, halogen, and LED bulbs being less affected than Fluorescent, Compact Fluorescent, and HID bulbs. Regularly turning a bulb on and off reduces its ARL. In practical terms, a bulb used in a scenario where it is frequently turned on and off throughout the day will likely have a shorter ARL compared to a bulb used in a setting where it is turned on and off less frequently, such as once a day.
The article also highlights that ARL tests are conducted under conditions representative of typical usage. If a bulb is exposed to abnormal conditions, such as extreme temperatures (hot or cold), moisture, or vibrations, the ARL obtained in the test may not be achievable in real-world scenarios. The analogy of a marathon runner is apt – just as a runner's performance is affected by environmental conditions, a bulb's ARL is influenced by its operating environment.
To provide a comprehensive overview, the article includes typical ARL values for various types of bulbs:
- Incandescent: 750-2,000 hours
- Fluorescent: 24,000-36,000 hours
- HID (High-Intensity Discharge): 10,000-24,000 hours
- Compact Fluorescent:
- Plug-in: 10,000-20,000 hours
- Screw-based: 8,000-10,000 hours
- Halogen: 2,000-4,000 hours
- LED: 40,000-50,000 hours
These values reflect the expected lifespan of each type of bulb under normal operating conditions, providing consumers and professionals with valuable information when selecting lighting solutions for specific applications.
