LED Selection and Design Issues, Part 2

LED Selection and Design Issues, Part 2Let’s look more in-depth at the temperature and moisture issues identified in our previous issue.

Problems arising from incorrectly specified LED lighting components put maintenance into a head scratching phase, trying to solve mysterious frequent failures. The cause is nearly always a lighting equipment selection problem rather than a problem with LED lighting per se.

Various LED lighting components, and even packaged systems, come in various temperature ratings. You can use the temperature rating as a product selection filter. But make sure the temperature you use is the temperature at the point of installation under actual conditions of use.

For example, it might seem smart to set your selection limit at the fairly standard rating of 120 DegrF for the outside of a building in Arkansas. Hot as those Arkansas summers get, they don’t get 120 DegrF hot. Or do they? Outside next to an asphalt parking lot with reflective surfaces intensifying the sunlight hitting that fixture, it could easily hit 130 DegrF on a 100 DegrF day. The high ceiling spaces of warehouses and factories, similarly, can be much hotter than the ambient air temperature out on the facility’s lawn.

One way LED manufacturers can help their LED fixtures handle the heat is to add venting. But this exacerbates another major problem that you must consider in LED selection: moisture. Yes, you can caulk those vents shut but that traps the heat and lowers the effective temperature rating.

You need to select equipment that can handle both the temperature and humidity conditions of the application.

« Part 1 |  Part 3 » | Source: Mark Lamendola | Mindconnection

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