Intrinsic safety instruments and minimum ignition energy
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The intrinsically safe instruments use E*a, along with ia-rated safety barriers. The question is: how can I determine whether this intrinsically safe circuit is capable of meeting the minimum ignition energy requirements in our facility? For example, the environment involves hydrogen, but when selecting instruments or safety barriers, we only have an explosion protection rating of ia – how can I determine whether this ia intrinsically safe circuit can be used in Zone 0 for hydrogen? (Or, any intrinsically safe circuit of type IA can be used in all Zone 0 areas, regardless of the type of gas.) What if there are flammable gases or dusts present on site, but no data is available regarding the minimum ignition energy of those gases? What should be done in such a case? In simple terms, it’s a matter of selecting intrinsically safe instruments and their safety barriers; those with experience are welcome to share their insights.
Intrinsic safety explosion-proof instruments are all certified; as long as the explosion protection rating of the selected instrument is higher than or equal to that of the explosion-proof area, there will be no problem.
For example, the one I used in Zone 0 on-site – does that mean that any intrinsically safe circuit of IA rating (instruments, safety barriers, cables of IA rating) can be used in my Zone 0? Is there no difference in choosing instruments and safety barriers between the Zone 0 of hydrogen and that of benzene?
Intrinsic safety – it means there is no danger, as the electrical sparks generated will not ignite any combustible material.