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in IEC 60079-11 two kinds of faults are defined; countable and non-countable faults, for intrinsically safe circuits, but if we have a circuit with alot of capacitors, inductors, ICs ,... how can I consider all faults,?they may be alot of faults

Intrinsically safe systems take active measures to limit the temperature, voltage, current and capacitance below levels of sufficient energy to produce the minimum ignition energy within the environment the system is placed. Protection level "ib" requires 1 level of fault protection while level "ia" requires at least 2 levels of fault protection. Countable faults are the active measures taken to limit energy such as current limiting resistors, voltage limiting Zener diodes, fuses and defined safe distances. The total capacitance and inductance of the circuit is limited to ensure the voltage and currents are not exceeded during closing and opening of the circuit. The issue is not how many components make up the total but that the total can't exceed a hazardous level.

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Vitreous Humor
"Eye can see clearly now..."

thanks for your reply.

but I still dont know exactly, "how can I exactly analyze my circuit, to fined out if it remains intrinsically safe or not?"  .  the standard IEC 60079-11 just discuss about resistive, capacitive or inductive circuits, and there are just some curves for them, but, if my equvalent circuit is compoused of these three parts (including ; resistance, inductance, capacitance), there is not any curve (minimume ignition curves) for these compound circuit.  and if I should gurantee that my circuit is in category "ia" , how can I cosider two faults in my analysis in circuits to fined out " oh, this circuit under 1 or 2 faults still remains intrinsically safe".

please help me