Industrial areas that present a risk of fire or explosion are called hazardous locations. Sensors installed in these areas can potentially ignite flammable vapors, dust, or fibers. To prevent a disaster, these sensors must be designed in a way that eliminates risk. At Automation Products Group, Inc. (APG), we provide specialized sensor that are safe to use in hazardous locations. In this post, we’ll cover the basics of hazardous locations, namely protection methods and hazard types as defined by CSA International, a globally recognized testing and certification organization.
Protection Methods
There are several methods of protection against fire and explosion. The two we most often use at APG are intrinsic safety wiring and explosion proof housings. As their names suggest, one is a wiring and power management technique, with the other is a containment technique with a durable housing.
Intrinsically safe wiring is a power management technique. By limiting the amount of electricity in a device, to the point that it can’t produce an ignition, we create a device that’s intrinsically safe. Without the potential of ignition, safety becomes intrinsic to the design of the device.
Explosion proof, also known as flame proof, uses a housing that will withstand and contain an internal spark, ignition, or explosion. In other words, if a sensor’s electronics do ignite vapors or dust inside the sensor housing, it will never break through the actual sensor housing, thereby eliminating any chance of an explosion or fire.
Hazard Types
Not all hazardous locations are created equal. CSA has broken these areas down into classes, and divisions for North America, and classes and zones for Europe. While the terms vary slightly in specificity, they are consistent in purpose.
For both continents, classes defined the type of hazard. The three categories are class 1 for vapors, class 2 for dust, and class 3 for fibers. Divisions, for North America, and Zones, for Europe, identify the extremity of the hazard. There are only two divisions:
Hazard is likely (division 1)
Hazard exists under abnormal conditions (division 2)
Conversely, there are three zones:
Hazard is constant (zone 0)
Hazard exists during normal operation (zone 1)
Hazard does not normally exist (zone 2)
Using good protection methods, and keeping sensors in their appropriate areas can keep hazardous locations safe. Our sensors undergo rigorous testing to ensure they are safe and properly marked.
Our Measurement Experts welcome questions about hazardous locations and protection methods. If you’d like to know specifically about our products, give us a call or send us an email.
WRITTEN BY
Sami T.
Sami Thompson is APG’s Marketing Technical Writer and has been with the company since 2022. With a master’s degree in English from Utah State University and a 40-page thesis publication under her belt, Sami has a demonstrated strong writing background. In her free time, Sami enjoys reading and birdwatching.