Intrinsically Safe Energy Storage Calculator
Stop guessing your energy budgets. Use our interactive tool to instantly assess whether your stored energy in capacitors (C) and inductors (L) meets the strict limits of IEC 60079-11.
How it Works:
Select Gas Group (IIC, IIB, or IIA).
Input Component Values (Capacitance/Voltage or Inductance/Current).
Apply Protection Level (Ex ia/ib or Ex ic).
Get Instant Assessment (Safe, Warning, or Redesign Required).
Intrinsically Safe Energy Storage Calculator
Calculate stored energy for IEC 60079-11 compliance
Capacitor Stored Energy Formula
E = ½CV² where C is capacitance (farads), V is voltage (volts), E is energy (joules)
Inductor Stored Energy Formula
E = ½LI² where L is inductance (henries), I is current (amperes), E is energy (joules)
⚠️ Indicative Assessment Only:
- This calculator provides a preliminary assessment based on simplified IEC 60079-11 principles. While it serves as a powerful educational and informational guide for initial design, it does not account for circuit-specific tolerances, temperature effects, or complex fault interactions. Formal certification requires comprehensive analysis and physical spark-ignition testing by an accredited Notified Body or ExCB.
Why use this tool?
ByteSnap Design’s expert engineering teams have delivered 98% of projects on-time and on-budget since 2008. We apply our project evaluation framework to your specific requirements across:
Pre-Compliance Verification: Catch energy violations before you submit to a Notified Body.
Spark Testing Insights:Based on the official ignition curves for all major gas groups.
Regulatory Compliance: ATEX (Hazardous areas), IEC 62304 (Medical), and ISO 26262 (Automotive).
Safety Factors Included: Automatically applies the mandatory 1.5x safety factor for Zone 0 and 1.
Does your IS design need a formal compliance review?
IS energy storage calculator FAQs
Q: How do I determine the allowable energy for a Zone 0 circuit?
Allowable energy is not a fixed number; it is derived from the ignition energy of the specific gas group (IIC, IIB, or IIA) divided by the required safety factor. For Ex ia (Zone 0) compliance, you must apply a 1.5x safety factor to both voltage and current before checking against the ignition curves in IEC 60079-11
Q: Does this calculator account for PCB parasitic capacitance?
This tool provides an indicative assessment of discrete component values, such as bulk capacitors and power inductors. In a final technical file for a Notified Body, you must also include parasitic elements, such as PCB track capacitance and cable parameters, which typically add around 95nF per kilometer for instrumentation cabling.
What is the difference between Ex ia and Ex ic energy limits?
The primary difference is the safety factor and fault tolerance. Ex ia (Zone 0) requires the circuit to remain safe even after two simultaneous countable faults, applying a 1.5x safety factor. Ex ic (Zone 2) only requires safety during normal operation with a 1.0x safety factor, significantly increasing your available power budget.