What is meant by Intrinsic Safety (I.S)

What is meant by Intrinsic Safety (I.S)

Intrinsic Safety (I.S) is a protection technique used in hazardous areas to ensure that electrical equipment can operate safely without igniting flammable gases, vapors, or dust. The concept involves designing electrical circuits and devices so that they are incapable of releasing sufficient energy, even under fault conditions, to cause ignition of the surrounding hazardous atmosphere.

Key aspects of Intrinsic Safety include:

  1. Energy Limitation: The primary principle of Intrinsic Safety is to limit the electrical and thermal energy in a circuit. This is achieved by using components and circuit designs that ensure any sparks or heat produced are below the levels required to ignite a specific hazardous atmosphere.

  2. Fault Tolerance: Intrinsically safe systems are designed to remain safe even if there are faults, such as short circuits or component failures. This involves implementing redundancy and robust design practices to ensure that safety is maintained under various failure conditions.

  3. Certification and Standards: Equipment and systems designed to be intrinsically safe must adhere to rigorous standards and undergo certification processes. Common standards include those from the International Electrotechnical Commission (IEC) such as IEC 60079-11, and standards from other organizations like ATEX in Europe and NEC in the United States.

  4. Use in Hazardous Areas: Intrinsically safe equipment is commonly used in industries where explosive atmospheres are present, such as oil and gas, chemical processing, mining, and pharmaceuticals. Typical applications include sensors, instrumentation, communication devices, and control systems.

  5. Maintenance and Installation: Installing and maintaining intrinsically safe equipment requires careful consideration to ensure that the integrity of the safety measures is not compromised. Special wiring practices, barriers, and isolators are used to maintain safety from the power source through to the field devices.

  6. Low Current and Voltage: In signal and control circuits that can operate with low currents and voltages, the intrinsic safety approach simplifies circuits and reduces installation costs compared to other protection methods.

  7. High-Power Exclusion: High-power circuits such as electric motors or lighting cannot use intrinsic safety methods for protection