We often describe the Cygnus 1 Ex Ultrasonic Thickness Gauge as “Intrinsically Safe, certified to Zone 0, suitable for hazardous areas.” But what do these technical claims actually mean? In this campaign, we aim to unpack the terminology and explain the regulations behind equipment used in explosive or hazardous environments.

To celebrate our best-performing product, 3 years since launch, we’re offering a FREE* Cygnus S2C-Ex Probe when you order a Cygnus 1 Ex PRO Anniversary kit (includes a Cygnus 1 Ex PRO Gauge and a Cygnus T5B-Ex Probe)!

Cygnus 1 Ex is Intrinsically Safe

When we say the Cygnus 1 Ex is Intrinsically Safe, we mean it’s designed to operate with extremely low energy levels—not enough to ignite a hazardous atmosphere, even in the event of a fault.

Intrinsic safety is a protection concept used in hazardous area environments. It ensures that:

• Power levels are kept low
• Stored energy is minimized
• Sparks and heat capable of igniting gases or vapours are prevented under any conditions.

This makes it possible for intrinsically safe equipment to be certified for:

• Zone 0 (where explosive gases are present continuously or for long periods)
• Zone 1 (likely to be present during normal operations)
• Zone 2 (unlikely to be present in normal operations).

In contrast, other safety methods like Explosion-proof (or flame-proof) equipment are designed to contain an internal explosion—but can’t be used in Zone 0. These systems are typically rugged and sealed but still allow ignition within the enclosure.

Understanding Equipment Protection Levels (EPLs)

Every Ex-certified device, including portable and fixed equipment, must have a Certificate of Conformity (C-of-C). This certificate includes the Equipment Protection Level (EPL), designated by a code such as “Ga”, “Gb”, or “Gc” for gas environments.

Only devices rated “Ga” are certified for Zone 0 use. Here’s how Zones, EPLs, and protection concepts relate:

Zone  -  EPL  -  Code  - Protection Level - Common Method

Zone 0  -  Ga  - Very high – Intrinsic Safety

Zone 1 -  Gb  -  High – Explosion-proof or Intrinsic

Zone 2 -  Gc  -  Basic – General Ex-rated equipment

The Cygnus 1 Ex holds a “Ga” EPL, confirming its suitability for Zone 0 environments.

No Hot Work Permit Required

A major benefit of using the Cygnus 1 Ex is that it does not require a Hot Work Permit, allowing it to be used anytime, anywhere in hazardous zones.

Hot Work Permits are usually required for tools or processes that might generate sparks or heat—activities that could ignite flammable gases. Securing a permit can be a lengthy and costly process, typically involving:

• Formal risk assessments and documentation
• Gas monitoring by a qualified person
• Oxygen and flammable substance level checks
• Emergency response readiness
• Standby rescue equipment
• Nitrogen purging of tanks and pipes
• Potential shutdown of plant operations.

The intrinsically safe design of the Cygnus 1 Ex eliminates these risks, saving time, money, and operational delays.