In industries like mining, oil and gas, and chemical processing, electrical equipment often operates in hazardous environments where flammable gases, vapours, or dust are present. In such settings, even a small spark or heat generated by electrical circuits can ignite an explosion. This is where intrinsic safety (IS) barriers come into play, acting as a critical line of defence to ensure that electrical systems remain safe, even in the most volatile conditions.
What Are Intrinsic Safety Barriers?
Intrinsic safety barriers are protective devices designed to limit the energy, both electrical and thermal, transmitted into hazardous areas. Their primary function is to ensure that the energy levels in circuits are kept below the threshold that could ignite an explosive atmosphere. Learn more about the difference between the intrinsically safe products and explosion-proof junction boxes.
These barriers are typically installed between field devices (like sensors or transmitters) located in hazardous zones and the control systems in safe zones. By restricting voltage and current, they prevent sparks or excessive heat that could lead to ignition.
How Do Intrinsic Safety Barriers Work?
IS barriers operate on a simple but effective principle: energy limitation. They incorporate components such as:
- Zener diodes: To clamp voltage to a safe level.
- Resistors: To limit current flow.
- Fuses: To disconnect the circuit in case of fault conditions.
Together, these components ensure that even under fault conditions, like short circuits or component failures, the energy remains below the ignition threshold.
There are two main types of IS barriers:
- Zener Barriers: These are passive devices that rely on grounding to divert excess energy. They are cost-effective but require a reliable ground connection.
- Galvanic Isolators: These use transformers or opto-isolators to provide isolation between the hazardous and safe areas. They don’t require grounding and offer better noise immunity, making them suitable for more complex systems.
Why Are Intrinsic Safety Barriers Important?
The importance of IS barriers goes beyond just safety, they are also essential for regulatory compliance. Standards such as IEC 60079, ATEX, and NEC/CEC mandate the use of intrinsic safety in classified hazardous locations.
Here’s why they matter:
- Explosion Prevention: They eliminate the risk of ignition from electrical faults.
- Equipment Protection: They safeguard sensitive field devices from overvoltage and overcurrent.
- Operational Continuity: By preventing accidents, they reduce downtime and maintenance costs.
- Regulatory Compliance: They help meet international safety standards, avoiding legal and financial penalties.
Applications in Mining, Oil, and Gas
In the mining industry, IS barriers are used in equipment like gas detectors, pressure sensors, and communication systems. These devices often operate underground where methane and coal dust can create explosive atmospheres.
In oil and gas, IS barriers protect instrumentation used in drilling rigs, refineries, and pipeline monitoring. For example, temperature and pressure transmitters in these environments must be intrinsically safe to prevent ignition from electrical faults.
Design Considerations for Intrinsic Safety Systems
When designing an intrinsically safe system, engineers must consider:
- Circuit Classification: Determining whether the area is Zone 0, 1, or 2 (or Class I, II, III in North America).
- Device Certification: Ensuring all components are certified for IS use.
- Wiring and Installation: Using approved cables and connectors that maintain the integrity of the IS system.
- Maintenance and Testing: Regular inspection to ensure barriers are functioning correctly and haven’t degraded over time.
Challenges and Limitations
While IS barriers are highly effective, they do come with limitations:
- Power Restrictions: They can only be used with low-energy devices.
- Distance Limitations: Signal degradation can occur over long cable runs.
- Complexity in Retrofitting: Adding IS barriers to existing systems may require significant redesign.
Despite these challenges, the benefits far outweigh the drawbacks, especially in high-risk environments.
Intrinsic safety barriers are a cornerstone of electrical safety in hazardous industries. By limiting energy to safe levels, they protect both people and equipment from the devastating consequences of explosions. Whether you’re working in mining, oil and gas, or chemical processing, understanding and implementing IS barriers is essential for safe and compliant operations.
At Transtech, we supply high-quality electrical components such as IS barriers to ensure efficient operation of your process in hazardous area. They can be installed either in safe zone or hazardous zone, realizing transmission of 4-20mA signal from safe zone to the hazardous area and vice versa.
Featured Products:
T-series | DIN-rail mounting intrinsically safe barrier
- The T-series provides versatile isolated safety barriers with a wide range of analog and digital I/O, suitable for various industrial applications, enhancing operational safety and compliance.
H-series | Backpanel mounting isolated safety barriers
- Designed for backplane mounting, the H-series offers isolated safety barriers suitable for various digital and analog input outputs, ensuring reliable protection in hazardous environments.
SIL-rated Intrinsically safe barrier
- This SIL-rated IS barriers are suitable for HART sensors in hazardous area applications. These barriers provide reliable signal isolation and protection, meeting stringent functional safety standards.
Contact us today or email info@trastech.com.au to speak with one of our experts and we will advise you on the products that meet your requirements or custom-made solutions.