Most electric equipment creates so-called “electric arcs.” Electric arcs are internal sparks in switches, connectors, motor brushes, and other places.
Next to this, electric equipment generates heat. For instance, think about an iPhone that has been used for an extended period. The hot surface can lead to an electric device becoming an ignition source. It is essential to take measures to prevent ignition sources in hazardous areas, and there are multiple ways to do so.
Intrinsic safety is one method to prevent electrical equipment from becoming an ignition source. But what is precisely the meaning of intrinsically safe? And when is equipment classified as intrinsically safe?
This article will thoroughly explain intrinsic safety, intrinsically safe equipment, and more.
Intrinsically safe meaning
Intrinsically safe means that a device cannot produce a sufficient spark or heat to ignite in an explosive atmosphere, so a special protection technique is used to prevent an electric instrument from becoming an ignition source. Intrinsic safety is achieved by limiting the thermal and electrical energy available for ignition.
When manufacturers design or modify equipment that has to guarantee intrinsic safety, there are more considerations regarding the product that could be taken into account, for instance:
- Control of the temperature of the components. Safety measures like current limiting resistors and fuses are taken to control the temperature of the components.
- Eliminating or decreasing internal sparkling. The potential to spark is prevented by limiting the available energy in the whole system.
- Eliminating component spacing. If there is a danger of dust or similar substances entering the circuit, component spacing and isolation become significant.
Concluding on the meaning of intrinsically safe, it is one of the common approaches to the design of equipment used in hazardous areas to prevent ignition sources.
Intrinsically safe and flameproof
Another common technique used to prevent explosions in hazardous areas is flameproof equipment. Flame proof equipment is often called “explosion proof” equipment, but those terms are not precisely the same. Flame proof equipment is enclosed with heavy protection; in this way, explosions can still occur within the enclosed guard. Subsequently, we come to the question of which risk reduction method is the best. The answer depends on the situation; both ways are not mutually exclusive. Therefore we have provided advantages and disadvantages of every technique.
Flame proof equipment:
- Advantage: the design of the enclosure is simple, and this method is also suitable for high-power equipment
- Disadvantage: the enclosure makes the equipment relatively heavy and expensive. It is also not allowed to open the enclosure when the equipment’s power is turned on.
Intrinsically safe equipment:
- Advantage: This method of safe operation is relatively cheap to implement, and there is no requirement regarding special cabling. Maintenance can also be done live, so the power of the plant can stay on.
- Disadvantage: Intrinsic safety is only suitable for low-power equipment, for instance, smoke detectors and beacons.
Intrinsically safe equipment
A wide variety of intrinsically safe equipment is available for use in hazardous areas. Think about smartphones, cameras, and air conditioners. Cobic-Ex also offers a variety of intrinsically safe torches.
This does not mean that using intrinsically safe equipment is a sufficient measure to prevent all the risks in a hazardous area on itself. Intrinsically safe equipment can best be used where combustible substances are present, and the risk of an ignition source has to be reduced.
Intrinsic safety barrier
The intrinsic safety barrier is also a relevant term concerning intrinsic safety, but what is it exactly? The intrinsic safety barrier limits the energy that can be carried from a safe to a hazardous area. The barrier is located between the control equipment and the devices in the hazardous area. By reducing the energy input into hazardous areas, the intrinsic safety barrier prevents the ignition of potentially explosive atmospheres.
There are two types of intrinsic safety barriers:
- Isolated barriers. Galvanic isolation is provided to prevent signal distortion and dangerous surges regarding measurement and control circuits. Next, the interface converts measurement and control signals, standardized and split.
- Zener barriers. These barriers are also called “shunt-diode safety barriers.” This barrier prevents the transmutation of high energy levels from neutral to hazardous areas.
Below, we have provided an example of how an intrinsic safety barrier works.
Intrinsically safe and ATEX
Understanding the connection between intrinsic safety and ATEX is essential, starting with understanding ATEX zones.
How are ATEX and intrinsic safety related to each other? ATEX and intrinsically safe equipment are suitable for hazardous areas, but what is the difference?
The ATEX directive describes specific minimum safety requirements for controlling explosive atmospheres. To control those explosive atmospheres, different ATEX protection methods can be implemented. One of these protection methods is intrinsic safety.
Concluding on the relationship between ATEX and Intrinsic safety, using intrinsically safe equipment is one of the measures that could be undertaken to prevent risks according to ATEX standards. Other lighting standards may also be taken into account.
Terminology: intrinsically safe vs. explosion proof
Within the industries that deal with hazardous areas, there are many synonyms for what are essentially Ex certified-products. Ex certified means that the product is suitable for use in a potentially explosive atmosphere. There are many different types of product certifications based on region. For example, ATEX (EU), IECEx (World Wide), or UKCA/UKEX (United Kingdom).
Differences in languages
Intrinsically safe is commonly used in the United Kingdom when referring to an Ex certified product. This can be unclear because it does not necessarily mean that the product uses intrinsic safety as a protection method.
In international English, Ex-certified products are usually referred to as “explosion proof” products. This may also be a tad confusing because this would suggest that the product could withstand an explosion, which is not the case. The product is made not to form an ignition source.
Intrinsically safe vs. Non-incendive
Hazardous areas are classified into zones, based on their nature and te expected danger. Intrinsically safe products may be used in Zone 1 (gas) and 21 (dust). These are more dangerous areas than zone 2 (gas) and 22 (dust), for which non-incendive products are certified.
To conclude, do not be confused when a product is referred to as either intrinsically safe, explosion proof, or flame proof. Ensure that the certification fits your location and specific hazardous area.
Hopefully, you have learned more about the meaning of intrinsically safe, intrinsically safe equipment, and other concepts. For more information about related subjects, please look at our blog page. For questions or remarks, please don’t hesitate to contact us at info@cobic-ex.com.
