What does this mean in practical terms? In this article, we compare the differences between the two and examine the impact on the user. We specifically look at areas such as maintenance, ease of installation, and how future-proof these types of luminaires are for wireless technology.
When selecting, for example, an explosion-protected luminaire, certification is one of the most important factors to consider. Simply put, the correct Ex luminaire must be selected for the Ex Zone in which it will be installed. If, for example, the area has been classified as Ex Zone 1, you must select a luminaire that is approved for at least Zone 1.
In addition to this, it is also important to consider the construction method used for the product. The construction method has a significant impact on how user-friendly the luminaire is. There are several different construction methods, but the two most common are Ex e “increased safety” and Ex d “flameproof enclosure”.
Ex e: products approved according to this standard are designed to maintain a low temperature and prevent arcs, sparks, and hot spots from occurring. In short, this protection method focuses on preventing the risk of accidents by preventing ignition from occurring.
Ex d: products approved according to this standard must be able to contain an explosion and withstand the resulting pressure that develops. The luminaire must prevent fire or sparks from escaping the enclosure and entering the surrounding explosive environments. This protection method therefore focuses on containment rather than prevention.
Maintenance
One of the biggest differences between an Ex e / Ex d product is how easy they are to maintain.
Ex d products often have extensive bolt connections that must be opened to access internal components during maintenance work. In addition, the area often needs to be declassified before work involving opening an Ex d enclosure is permitted.
With Ex e protection, it is often easy to disassemble and replace the product.
Installation
An Ex d product is often a heavy and robust metal construction with a substantial bolt connection with many screws in the cover, or with a threaded cover with many threads. This often results in a longer installation process.
An Ex e product is often made of plastic and has easily accessible connection points, making it easy to install.
Choosing Ex e or Ex d Luminaires
Due to the properties of gas or vapor at low temperatures, most Ex d luminaires are not suitable for installation in ambient temperatures below -20 °C.
Since Ex e luminaires are designed to prevent an ignition source from occurring (rather than preventing gases from entering or exiting), they often have a much wider range of permissible ambient temperatures and perform better in ambient temperatures below -20 °C.
Ex d and Explosion Group
If your environment requires explosion group IIC, it can be difficult to find a suitable Ex d luminaire. Since explosion group IIC requires gaps with very high tolerances that are complex to manufacture, there are fewer Ex d products approved for IIC. They tend to be expensive and difficult to obtain.
What is Best for Wireless Technology
Introducing new technology in Ex areas is always a challenge, but we are beginning to see the emergence of smart / IoT-enabled luminaires.
As we described earlier, the enclosure of an Ex d luminaire must often be thick metal to contain an explosion and withstand the resulting pressure. Just as it can be difficult to get a good Wi-Fi signal in a house with thick walls, an Ex d enclosure is not the best solution for wireless technology. However, with the Ex e protection method, there is much greater potential to integrate this type of technology into the luminaire.
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