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LED Testing & Application
A Call for More Rigorous Testing
In a recent commentary in LD+A, columnist Jerry Plank of Wilger Testing argues LED luminaire manufacturers should take the lead on more ambitious fire-related product testing, rather than relying on UL and other labs.
The safety standards created to address LED products are flawed, in as much as the potential hazards are not addressed or identified. When product-testing schemes are flawed and don’t address all the risks associated with a certain class of products, a fire in the field can ensue leading to product recalls. Safety-related product recalls can be voluntary or required by the CPSC (Consumer Product Safety Commission). They can affect future business, as users naturally become reluctant to use that product. In other words, we all lose when LED products are involved in recalls due to fires, and when the safety standards fail to provide the level of safety required to protect property, personal injury, or life.
The testing of solid-state LED sources in products should not be that expensive or difficult as the principles of fire and electrical shock hazard have been known since the early 1900s. Further, solid-state devices have been on the market for over 30 years with excellent safety records and proven safety programs. Why then are LED lighting products being scrutinized so closely by safety test laboratories, but still creating fires from use? Some would suggest that safety test houses are reaping the benefit of creating standards for profit rather than addressing real-world concerns.
OUT IN THE FIELD
Real-world concerns about LED products have to do with electrical shock hazards and, as we know, less than 60 volts DC, or 30.0 volts RMS eliminates an electrical shock hazard in most dry locations. Voltage in electrical circuits is analogous to pressure and it takes greater than 60 volts DC or 30.0 volts AC (pressure) to break through the skin for one to receive an electrical shock. Once the voltage (pressure) is great enough, the skin is broken down and an electrical shock has occurred. The culprit in the electrical shock is the amount of current available once the skin is bridged.
The available current in a circuit also determines how much of a fire risk is involved, as current through conductors and components results in heat. It is the resultant heat from the current levels that allows components and wires to operate at temperatures that can ignite combustible materials in the LED product or adjacent to the LED product. In other words, thermoplastic parts used in the product can ignite, as can the surface to which the product is mounted. A product safety program must then be developed that addresses normal and abnormal conditions where a current overload can occur. Safety devices such as fuses or the like should be required to eliminate that risk.
While safety standards typically address a minimum level of safety, a product that is Listed by an NRTL is often considered to be free of risks such as fire or electrical shock. But users need to understand that an NRTL Listing does not claim that the product is free of risks--only that the product is compliant with the standard used. Manufacturers often make the mistake of not conducting their own test program to uncover all potential faults that could lead to a product mishap. It would prove beneficial for manufacturers to subject their products to a risk analysis program that looks to uncover all potential problems and what could lead to a loss.
If we as an industry want to avoid product recalls on new technologies then we must develop test programs for our products that are more real world. As an industry we should be more proactive and develop our own product testing standards and not rely on others to create standards that are expensive, ambiguous and flawed.