What Are I.S. Barriers and Why Are They Needed in Hazardous Environments?

In industries such as chemicals, oil & gas, gas processing, storage facilities, and many other applications that involve hazardous areas, the risk of ignition or heat generation can potentially lead to explosions.
I.S. Barriers (Intrinsic Safety Barriers) act as a protective wall, ensuring that signals from field devices are safely and reliably transmitted back to the control room without creating any ignition risks.

Comparison: Traditional Zener Barriers vs. Modern Galvanic Isolators

Zener Barriers – An Older Solution with Many Limitations

Zener Barriers function by:

Using resistors to limit the current entering the hazardous area
Using Zener diodes to divert excess voltage/current to ground during a fault
Using a fuse to protect Zener diodes during overload conditions

Major drawbacks:

Requires a dedicated I.S. grounding system — complex and costly
Voltage drop, resulting in reduced power available to field devices
Installation limitations — must be mounted close to the grounding point
Safety risks if the grounding connection fails

Galvanic Isolators – Advanced Isolation Technology

Using transformers and opto-isolators, Galvanic Isolators create full galvanic isolation between:

Input
Output
Power supply

Outstanding advantages:

No special grounding required → reduces installation cost
Zero maintenance throughout product life
Excellent noise immunity, eliminates ground loops
High signal accuracy
Certified SIL2/SIL3 according to IEC 61508 / IEC 61511

SIL2/SIL3 – Safety Integrity Levels Explained

Different types of risks originate from plants or plant components. As risks increase, the requirements for the Safety-Related System (SRS) also increase.
IEC 61508 and IEC 61511 define four Safety Integrity Levels (SIL), indicating how much risk reduction a system can provide. The higher the SIL level, the greater the risk reduction.

SIL1 — Basic protection
SIL2 — High level of safety
SIL3 — Very high level of protection
SIL4 — Extremely stringent safety level

PR electronics’ I.S. Barriers are certified SIL2/3 using the Full Assessment method, not the Proven-in-use method, offering:

Longer Proof Test Intervals
Higher system reliability
Better internal diagnostics

Why Choose I.S. Barriers from PR electronics?

As a leading manufacturer of intrinsic safety isolation devices, PR electronics not only complies with global safety standards but also sets stricter internal requirements:

All devices are based on Galvanic Isolation, not Zener Barrier design
SIL2/3 certification under IEC 61508 Full Assessment, integrating safety throughout the entire product lifecycle
Higher reliability with extended Proof Test Intervals
Superior internal diagnostics compared to Proven-in-use certified products
Global approvals: ATEX, IECEx, FM, UL, CSA, GOST

Superior Performance Features

Wide application range: The 9000 and 5000 series offer isolation solutions for all signal types — analog, digital, HART®, pulse, and universal inputs
Easy configuration: Supports a wide supply range from 24V AC/DC to 220V AC/DC, configurable via PC or detachable display
High accuracy: Series 5000 provides measurement precision below 0.1%
High galvanic isolation (up to 3.75 kVAC) and exceptional EMC immunity

Key I.S. Barrier Products from PR electronics

HART Repeater – 9106B / 5106B

Isolates HART communication
Powers HART field devices in hazardous areas

Universal Converter – 9116B

Supports RTD, Thermocouple, mV, Ohm, Voltage inputs
Converts to standard analog output signals

Pulse Isolator – 9202B / 5202B

Ideal for NAMUR sensors, flow counters, and switches
Ensures safe and isolated pulse transmission

I.S. Barriers – The Optimal Safety Solution for Modern Industrial Plants

Given the stringent requirements of explosion protection, PR electronics’ I.S. Barriers deliver:

Maximum safety (SIL2/3 – Full Assessment)
High signal accuracy
Zero maintenance
Full certified global compliance
Reduced installation costs (no I.S. grounding required)

These are the leading choices for oil & gas, chemical plants, pharmaceuticals, energy, and industries requiring high-level safety.

Conclusion – Contact Us for Consultation and Pricing

We are the official representative of PR electronics in Vietnam, providing technical support, installation guidance, and genuine warranty services.

For more detailed technical information, please visit PR electronics’ official website or contact our authorized distributor.

Vntech Group JSC is the exclusive distributor of PR electronics (Denmark) and other high-end industrial and automation products from Europe.
We are committed to delivering the best solutions and ensuring customer satisfaction.