Is the instrumentation design for the tank area intrinsically safe or flameproof?
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Is there anyone in charge of instruments in the tank farm? Are the instrument designs for tank farms generally based on explosion-proof principles? Is it still intrinsically safe?
Neither explosion-proof type of flame arrestment nor intrinsically safe design will be phased out. Tank areas are generally designed with explosion protection, as there are relatively few instruments in such areas compared to the number of devices; valves, level gauges, and level switches typically use 220VAC and 24VDC for power supply. To facilitate the design of other temperature, pressure, and flow meters, explosion protection is also used. Otherwise, on the indoor side, there will be half safety barrier signals and half flameproof signals, which makes the design process inconvenient. Managing the property owners is also troublesome. So it features a flameproof design. Of course, using an intrinsically safe design also complies with the regulations.
There are many instruments on site, which are usually intrinsically safe, such as remote-type magnetic flap level gauges, pressure transmitters (such as Rosemount), vortex flow meters, and so on.
Previously, the plant areas all used intrinsically safe systems, while it seems that the tank areas utilize flameproof designs. I’m not sure how everyone’s tank areas are designed; I’d like to find out
Mainly, electric valves require 220V power supply, and electromagnetic flowmeters need it more; for the rest, 24V is probably the standard
I think either flameproof or intrinsically safe works; if the field equipment is intrinsically safe, then the control room must be equipped with a safety barrier. During regular maintenance, if a circuit inspection needs to be carried out on-site, opening the intrinsically safe instrument has no impact ； The explosion-proof instrument must be powered off before its cover is opened, which makes it difficult to diagnose faults. As a user, intrinsically safe is the preferred option; some instruments cannot be made intrinsically safe, so explosion-proof alternatives must be chosen.
Is the tank area the place with the most valves and pressure transducers? Then the four-wire level gauge? I also said *all are intrinsically safe. Of course, using intrinsically safe systems also complies with the regulations. I have been working in design for over a decade. I’ve hardly ever seen intrinsically safe systems used in tank areas. Firstly, the control valves are flame-proofed, as are the level gauges; there are also level switches available for temperature, pressure, and flow measurement. Flammable, toxic, and explosion-proof. You can look for the design drawings of the plant’s tank area.
Whether to use flameproof or intrinsically safe design depends on the zoning of explosive hazard areas. If it is classified as Zone 0, then an intrinsically safe type must be used. For Zones 1 and 2, intrinsically safe or flameproof types can be used.