Industrial Lighting 101: Best thermal design for dirty industrial facilities
Upgrading the LED lighting in your industrial facility? Consider the ambient temperature at the ceiling height which is usually much higher than at floor level. Also, make sure the thermal design of the heat sinks and LED driver can handle that heat, as well as dust, gases and other manufacturing debris, otherwise the fixture will fail earlier than expected.
What should you consider when selecting LED lighting for industrial facilities, factories, steel mills, or operations that are hot, dirty and those where it is often impractical, if not impossible, to do maintenance on the lighting? There are three things you should consider.
1. Check the ambient temperature at the ceiling
First and foremost, when you’re up high in the ceiling, it’s usually pretty hot. Hot air naturally rises so the ceiling is typically the hottest area of any room. Even if you’re in a conditioned facility, the units are typically installed at 7-10 feet high so the fixtures will not benefit – the hot air will still get trapped at the ceiling.
If you’re talking about a factory, unconditioned warehouse, steel mill or foundry, it’s not uncommon for temperatures to reach 140-150°F or higher. You need to make sure you have a fixture with the best thermal design to handle these extreme temperatures as well as the dirty environment.
2. Get to know the heat sink design
There are many types of heat sinks but most are not good for harsh environments. Let’s look at the most common.
Sheet metal fixtures are one of the most common. When you think of this design, you have all of the electronic components, which don’t like heat, contained in the same metal box. With nowhere for the heat to go, the driver and the LED’s continue to get hotter, which can ultimately result in premature failure.
Poorly designed LED fixtures often have no real heat sinks to begin with. Many others have fins that will collect dust and other debris, creating an insulating layer that severely diminishes its capacity to dissipate heat, reducing its life and performance.
Another problem with flat sheet metal fixtures is that dust falling on the fixture has nowhere to go. Over time, it creates a thick layer which acts like insulation further retarding the fixtures already limited ability to dissipate heat, significantly reducing its life and performance.
Many fixtures cannot truly handle the heat when they approach the limits of their “rated” temperature and will dim themselves, reducing their light output by 30 or 40%. Often, this dimming starts well before the actual ambient temperature reaches its maximum “rating.” Make sure to read the fine print to see what happens to the output of the fixture you select when it reaches higher temperatures. If it isn’t on the spec sheet, you should demand to see it in writing from the manufacturer.
Conversely, our Essentials Series and CH1 Series fixtures have a dedicated heavy-duty vertical aluminum heat sink for each LED module. These heat sinks will heat up the air next to them and since there is space between the modules, it allows cool air from underneath to be pulled up and around the heat sink fins. Hot air will then rise away from the fixture. Therefore, the fixture creates both conduction as well as natural convection from that natural air flow.
3. Don’t forget about the driver
The LED driver is an electronic device that if not properly cooled by the fixture design, will have its lifetime significantly reduced by high ambient temperatures as well. This leads to more frequent need for potentially costly maintenance. Many fixture manufacturers do not take the driver into consideration in the thermal design. As the driver temperature case increases, the driver life quickly decreases, so it’s important to keep the driver case temperature low.
Driver Life vs. Driver Case Temperature
In our Essentials Series, the design of the fixture also ensures that we keep the driver cool as the driver compartment is completely made of aluminum with space around it to allow for vertical airflow and natural convective cooling. This design allows the driver to operate at a cooler temperature, ensuring its life and performance while also reducing future maintenance costs.
