This scenario seems impossible, but it is a real-life or death possibility. This is because Zone ratings are measured independently from temperature codes and gas group types defined within the ATEX and IECEx classifications.
Zone 0 is defined as an area where an explosive atmosphere is always present. Zone 1 is defined as an area in which an explosive atmosphere is likely to occur during regular operations due to scheduled maintenance, accidents, or leakage.
Temperature codes refer to the maximum surface temperature of any device component that can be exposed to a hazardous environment in a fault condition. A T1 rating can be up to 450°C (842° F), but a T4 rating cannot exceed 135°C (275° F). These significant differences between temperature codes often go unnoticed unless examined closely.
Likewise, gas group ratings require careful scrutiny. Group B type gas contains explosive gases like Hydrogen and Etheylene Oxide, while Group D type gas contains less volatile gases like Propane and Gasoline vapors. These differences often go unnoticed by safety professionals who rely solely on a Zone rating for guidance.
These T codes and gas ratings can confuse someone into believing a Zone 0 device with a T1 code, and a rating for group D type gases is safe for use in a Zone 1 environment that requires a T4 code and a rating for group B type gases. In this specific instance, the Zone 1 product rated for this environment is safer than the Zone 0 rated product.
All equipment safety ratings must be based on the potentially hazardous environment it may encounter as the current one may quickly change without you being aware of it. If you are unsure, analyze the work environment, determine the worst-case scenario, and equip your teams accordingly.
Nightstick, a global manufacturer of intrinsically safe, professional, portable LED lighting products that exceed industry standards in performance, quality, and user safety, has over fifty intrinsically safe products. You need to focus on completing your job with confidence, knowing your equipment was designed and rated for the highest levels of safety when your life depends on light.
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