Light Emitting Diode (LED) luminaires provide compelling benefits such as long-term cost savings, and safety advantages through longer life and durability. LED luminaires have lower maintenance costs, and improved instant restrike capability when compared to legacy luminaire types. In industrial applications, the proven lower total cost of ownership and increased safety for LEDs are the driving forces for LED luminaires to replace traditional light sources. As with any new technology, challenges exist in designing and maintaining an optimal system to withstand the intended application and environmental conditions. Common challenges and considerations include luminaire placement, the intensity/dispersion/quality of light, thermal management, material selection, and redundant safety and operating systems. The authors will examine best practices and common misconceptions in the selection and application of LED luminaires focusing on process and harsh/hazardous locations. The probability of success in maximizing reliability, safety & efficiency of LED technology in such applications is enhanced by utilizing proven design principles & methods. The selection methods and design principles will be explained using actual application examples and case studies.