ATEX & hazardous areas I
HAZARDOUS LOCATIONS IN MODERN FACTORY AUTOMATION: WHY PROPORTIONATE SPECIFICATION MATTERS
t was not too long ago that hazardous zones and production zones were reasonably well separated. The areas where explosive gases, vapors, or combustible dusts were present tended to stay in their own very specific environments, and the equipment operating in those areas was specified accordingly. Today, however, that distinction is less clear. As automation spreads deeper into processing, handling and transport operations, motors are increasingly required to operate in spaces that sit on the edge of hazardous zones. In these environments, explosive gases or combustible dusts are not continuously present, but they may occur during abnormal conditions or for brief periods of time. The engineering challenge is no longer simply “hazardous or not”, but rather “how hazardous, and how often”? Answering that question correctly can make the difference between a well-optimised design and an unnecessarily expensive, inefficient, and bulky one.
UNDERSTANDING THE ZONE In the ATEX and IECEx frameworks, hazardous areas are divided into zones. Zone 0 and Zone 20 represent the highest level of risk, where explosive gas or dust is present continuously or for long periods, while Zone 1 and Zone 21 apply where it is likely to occur during normal operation. In contrast, Zone 2 (gas) and Zone 22 (dust) apply where explosive atmospheres are not likely during normal operation and, if they do occur, will only exist for a short time.
The significance of this extends far beyond paperwork and has many practical ramifications. For example, the explosion-proof motors designed for Zone 0 or Zone 1 are typically engineered to withstand and contain an internal explosion. Their housings are thick and heavy. Flame paths are carefully designed to prevent ignition from propagating. Cable entry is typically via rigid conduit rather than standard connectors. These motors are robust, proven, and an essential part of making industrial operations possible in severe environments, but they are also large, heavy and highly expensive.
As such, if a machine only needs to comply with Zone 2 or Zone 22, specifying a fully Zone 1-complient motor is excessive. It adds weight to moving axes, increases inertia, may complicate mechanical integration and drives up cost unnecessarily.
AUTOMATION EXPANDS INTO THE GRAY AREAS
One reason for historical over-specification is simple availability. Both supply and demand for purpose-designed servo motors for Zone 2 and Zone 22 applications have historically been limited, so when faced with regulatory scrutiny and liability concerns OEMs have defaulted to the highest-rated solution available.
The need for motors tailored to these environments is growing as the nature of automation changes. Consider a robotic transport system moving unfinished assemblies from a welding cell to a paint spray booth. The booth environment may only occasionally present an explosive gas mixture, but any motor operating inside that space must comply with the appropriate hazardous location standard.
Similarly, in pharmaceutical manufacturing, servo- controlled gate valves meter fine powders with high precision. Under normal conditions the environment is controlled, but combustible dust may be present in abnormal situations. Grain handling systems, food processing lines, textile operations, and powder coating systems present similar challenges. These are not traditional heavy industries typically associated with hazardous zones, such as mining or petrochemicals. They are high- precision, high-value production environments that increasingly depend on servo technology. As a result, more machines now operate in the transitional space between conventional automation and classified hazardous areas. The specification approach must evolve accordingly.
30
June 2026 Instrumentation Monthly
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