Corrosion is what we call the deterioration of a metal as the result of chemical reactions with its surrounding environment. In highly contaminated environments, a luminaire with a specified 10- to 15-year lifespan could start showing signs of failure within its first year of use.

Corrosion is an especially pressing issue when it comes to these low- and mid-power LEDs, with which cost-conscious lighting practitioners often replace the high-powered LEDs original to certain lighting installations when the latter reach the ends of their lives. The problem is that the LED- die of a low- or mid-power LED product is mounted on a lead frame bearing a silver mirror surface that helps in light extraction – and silver, as anyone who’s ever polished a silver coffee service will know, can corrode. (In silver’s case corrosion is called tarnishing.) The result can be rapidly decreasing light output and a light color shift towards blue.

As cost-effective as low and mid-power LEDs can be, then, they should be reserved for the applications they’re best suited for. These include offices, shops, and others in which no production activity, for example, is producing corrosive substances like halogens and sulfur. 

In general, though, corrosive contamination is simply a fact of life for people who work with lighting. It’s a phenomenon to be reckoned with in various types of industry, in environments heavy with vehicular traffic, at power stations, at waste disposal facilities, and so on. These spaces typically emit gasses that are chemically incompatible with the materials that low and mid LED packages include – gasses that can degrade those packages’ effectiveness.

What that means is that you need to match LED lighting hardware to its correct application in each and every case: keeping silver-containing mid-power LEDs away from halogens is only the beginning. What it means as well is that your project development process needs to ensure that new luminaires intended for contaminated environments will be sufficiently resistant, thus delivering on their lifetime and performance specifications.

Here are two important pointers for professionals who take corrosion seriously: 

1.       Collect all the information you can about the application you’re specifying lighting for – What corrosive gases are present in your application that could affect your luminaires’ performance? If necessary, perform testing and measurements in the space in question. Factories and other industrial sites, metal shops, tunnels that conduct heavy vehicular traffic, and swimming pools are applications where the potential for corrosion is especially high. Then, too, certain regions of the world have air pollution severe enough that it could have a serious effect on your LED lighting system. (Needless to say, in addition to thinking about the corrosive properties of your application, you should take into account its other specifications, too.)

2.       Make sure the LED products you’re installing offer enough corrosion resistance – Determine what LED equipment is appropriate to your application – low and mid-power LEDs, for instance, or else high-power LEDs – on the basis of both your application’s requirements and on the equipment’s IP ratings. Bear in mind that the equipment’s robustness in the application will depend on the combination of these two factors. A high IP rating in itself may not guarantee that equipment is suited to an application.  

When it comes to special lighting applications, of course, the right piece of dedicated LED gear can be invaluable.

Take swimming pools, which are among the most demanding environments from a lighting perspective. Up until now, typical high-power or very strong mid-power LEDs have been used in pool applications, but a better bet is a dedicated light source equipped with specific features. One such light source is the Philips GentleSpace gen2, mid-power luminaire, ideal for hanging in pool houses. This luminaire bears an IP65 rating, indicating that it’s highly resistant to dust and moisture, but it also carries a special coating that protects its mechanical components against water vapor and the effects of chlorine and cleaning products. Its screws, bolts, and washers are also specially designed for performance in a pool building’s unique conditions.