Exi vs Exd transmitters in oil/gas industry
Exi vs Exd transmitters in oil/gas industry
(OP)
Hi
I have following question. Why do we often use Exi pressure, level or temperature transmitter in II zone (methane) with appropriate Intrinsic Safety isolators whereas total cost of combination Exi transmitter with Intrinsic Safety isolators mounted in control cabinet is more expensive than Exd transmitter mounted in the field alone?
Thanks in advance for answers!
I have following question. Why do we often use Exi pressure, level or temperature transmitter in II zone (methane) with appropriate Intrinsic Safety isolators whereas total cost of combination Exi transmitter with Intrinsic Safety isolators mounted in control cabinet is more expensive than Exd transmitter mounted in the field alone?
Thanks in advance for answers!





RE: Exi vs Exd transmitters in oil/gas industry
Occasionally you strike a situation where Intrinsic Safe is the only approval you can get for a particular instrument. I'm looking at a guided wave radar in a tank with Hydrogen gas. I dare say the barriers will be somewhere close by.
I don't see Exi in the Methods of Protection list Ex ia, EX ib, Ex ic
There are so many variations in hazardous location designation, can you share the location of the project, complete hazardous zone designation?
RE: Exi vs Exd transmitters in oil/gas industry
You can't only consider the prices of the equipment; you need to analyze the whole project. Usually, you need considerable structure, and you spend more time to implement an Ex d than an Ex i project.
The cost per hour of people involved in the installation and project + the cost of devices should be the right analyze before say that Ex i is more expensive than Ex d in all projects.
One example is the Wireless projects, where the cost of devices are higher than standard devices but you save money in time and installation cost.
I'd like to read an opinion from colleagues with more experience with this type of projects.
Thanks
RE: Exi vs Exd transmitters in oil/gas industry
It depends on the overall installation. There is no single answer which is universally accurate. The design engineer should be looking for the lowest cost solution which meets the technical requirements of the specification.