Which is more common in chemical plants: intrinsically safe instruments or flameproof instruments?

With the current development of chemical process instruments, intrinsically safe instruments are becoming more common, and their manufacturing costs are also decreasing. Most ordinary transmitters (for pressure, temperature, level, etc.) are certified for both intrinsically safe operation and explosion protection. Positioners also have lower costs in terms of intrinsically safe design compared to explosion protection designs, but the selling price by suppliers is not necessarily lower (due to the need to meet intrinsically safe requirements and investment costs associated with technological updates). Due to the development of electronic circuits, the power supply required for instruments has gradually decreased, allowing most of them to be made intrinsically safe. Additionally, in terms of cable manufacturing, the intrinsically safe cable has a simpler production process compared to the flame-retardant cable. Thanks to intrinsic safety, intrinsically safe designs are becoming increasingly common.