Intrinsic safety (IS) is an approach to designing electrical and electronic equipment for use in hazardous environments where there is a risk of flammable gases, vapors, dust, or fibers. The primary goal of intrinsic safety is to prevent sparks and limit energy levels to prevent ignition of potentially explosive atmospheres. This is crucial in industries such as oil and gas, chemical processing, pharmaceuticals, and others where flammable materials are present.
Key principles of intrinsic safety include:
Low Energy Levels
Intrinsic safety achieves safety by maintaining very low levels of electrical energy, ensuring that hot surfaces are not produced, and electrical sparks do not have enough energy to ignite flammable mixtures.
Voltage and Current Limitation
The design of IS circuits involves limiting the voltage and current supplied to equipment in hazardous areas. These limitations must not be exceeded under normal or faulty conditions.
Circuit Parameters
IS circuits consider various parameters, including voltage, current, resistance, inductance, and capacitance during design. Standards provide tables and characteristic ignition curves for different gases in hazardous areas.
Certification
Equipment intended for use in hazardous environments must be certified as intrinsically safe. Certification is provided by institutions such as UL (Underwriters Laboratories).
Barriers
IS systems typically use barriers such as Shunt Diode Barriers or Galvanically Isolated Barriers to limit energy and prevent ignition.
CompEx training (Competency in Explosive Atmospheres) is a certification program that provides training for personnel working in potentially explosive atmospheres. CompEx training covers the principles and practices of working safely in hazardous environments, including the understanding of intrinsic safety. This training ensures that individuals have the necessary knowledge and skills to work with equipment in hazardous areas and contribute to maintaining a safe working environment.
In summary, intrinsic safety is a critical aspect of electrical equipment design for hazardous environments, and CompEx training plays a key role in ensuring that personnel are competent and knowledgeable in working safely in these environments.