Design of intrinsically safe systems for dust hazardous areas
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Hello, fellow marine engineers. I have encountered some problems in engineering design, and despite searching through numerous resources, I still haven’t managed to figure them out. I’m reaching out here to ask for your help. The specific questions are as follows: 1. What is the difference between intrinsically safe transmitters used in dust-hazardous areas and those used in gas-hazardous areas? 2. What is the difference between the safety barriers used with intrinsically safe transmitters in dust-filled areas and those used with intrinsically safe transmitters in gas-filled areas? I hope the experts will kindly share their insights. Thank you! :)
It should be IIB for gases, and IIc for dusts
This question has been around for so long; whether it’s because it’s too easy or because there’s no point in discussing it, no satisfactory answer has emerged yet. Those who know about it, please come in and discuss it, okay?
As for temperature, the principle is the same: as long as the surface temperature of the transmitter is below the ignition temperature of the flammable gases or dusts in the environment. However, flammable gases have a minimum ignition current ratio, which is used to determine whether they belong to category IIA, IIB, or IIC. As for dust, it is classified into Category IIA: flammable particulates; Category IIIB: non-conductive dust; and Category IIIC: conductive dust, depending on its properties. Personal opinion, excerpted from the Code for Design of Electrical Installations in Explosive Atmospheres. If there are any mistakes, please feel free to point them out!
You’re right, thank you! What’s causing concern now is the difference in choices regarding safety barriers. . .