Everything You Need To Know About Intrinsically Safe Design

 

The term ‘intrinsically safe’ means a concept where an application or equipment is designed in a way that is safe for use in hazardous areas. Whether it is Intrinsically Safe Lighting in CO or other equipment, they are designed according to certain standards and have intrinsically safe certifications. For potentially explosive environments, it is mandatory to use intrinsically safe and explosion-proof electrical applications to avoid any spark or accidents. In this article, we will know in detail about the intrinsically safe design.

What Is An Intrinsically Safe Design?

The objective of an intrinsically safe design is to make sure that it prevents any electrical equipment from causing an explosion or generating heat. In hazardous areas, there is always the probability of explosions so the intrinsically safe equipment designs are deliberately enhanced to avoid any fire or other disasters. For areas where there are combustible gases, vapors, liquid, etc, intrinsically safe devices and equipment are a must.

Principle Behind Intrinsically Safe Design

The intrinsically safe design aims to reduce ignition hazards within an electrical circuit. The intrinsically safe design limits electrical energy to the extent that it does not cause a fire hazard in normal fault conditions when equipment is installed in a hazardous environment. In intrinsically safe the circuit is kept below levels that prevent ignition whenever there is a flammable substance. 

Intrinsically Safe Circuit Considerations

In intrinsically safe devices, every single electrical concept follows the I.S concept. When designing the applications, the designers take into consideration the Zener diode’s safety factor while calculating the ratings. Capacitors are used to block DC voltage while the capacity fuses are connected in the circuit to improve the safety of the application. If the environment uses both intrinsically safe and non-intrinsically safe then optocouplers and transformers are used to separate the connections. 

Difference Between Intrinsically Safe And Explosion Proof

Intrinsically safe devices are those that do not explode under combustible circumstances. Explosion-proof apparatus, on the other hand, does not come apart in the event of an eruption. In explosion-proof devices, the design is such that it contains the explosion while intrinsically safe devices are designed to prevent an explosion. Explosion-proof devices are more compatible in areas where it is difficult to design any internal circuit component that matches the I.S standard of intrinsic safety. The three most common features of Explosion-Proof Lighting in CO and other explosion-proof devices include:

- The ability to contain an explosion within its enclosure.

- Allows heat and gas to escape in the environment in a safe way.

- Comprise a heavy casing material.

Hazardous Areas And Their Classification

Hazardous zones are environments that consist of flammable and combustible substances like gases, vapors, and combustible particles. These combustible materials can react with electrical appliances installed in these areas and can cause explosions by putting the people working in these environments at risk. Some examples of hazardous systems include oil refineries, paint manufacturing factories, chemical plants, distilleries, spray booths, and mining, etc. Flour mills, food processing units, etc are also considered hazardous areas as they generate combustible particles as well.

According to the National Electric Code (NEC), there are two classifications of hazardous zones: Class 1 Division 1 and Class 1 Division 2. The Class 1 Division 1 hazardous zone comprises volatile and flammable gases while Class 1 Division 2 comprises flammable gases and liquids. 

Intrinsically Safe Certifications

- ATEX Certifications

ATEX is the most commonly used certification for the intrinsically safe equipment that is to be deployed in explosive environments. This certification is suitable for use in environments that comprise flammable substances like gases, liquids, and flammable dust. Equipment to be used in this environment should follow ATEX guidelines. The ATEX guidelines specify the mandatory protection levels in different atmospheres.

- IECEX Standard

Many countries have adopted the IECEX standards to maintain the safety of electrical applications in a hazardous environment. IECEX shows several protection levels and recommends what equipment should be used in different hazardous zones.